ESE's works engine tuner

[twotempi]

The 2CV engine also must be fairly sick if you can only get 2HP out of 602cc !!!!

[andrew a]

Thats a French rating. The 602 flat twin air cooled puts out 35bhp.

[husaberg]

You guys are sick

You have no idea how sick, Because now i am postings scooters
Ok these were a special part of Australian history.

[husaberg]

You have no idea how sick cause now i am postings scooters
Ok these were a special part of Australian history.

last one..............

[TZ350]

Reading about the sweat blood and tears of people and their racing efforts is always interesting.

[RAW]

That's not for me to divulge. Maybe Richard will tell.

Hello Frits,
This year
I have read this entire forum, some 630 plus pages
I have read the French forum, some 70 plus pages
I have read some 800 pages of the 8 pt forum of which describes this pipe system, i do not understand, why the secrecy ?

[Frits Overmars]

I get a fair amount of information from a lot of sources, but it is not up to me to spread that information further, because it is not my intellectual property.
I leave it to those sources to decide if, when and how much they want to reveal. I think it is a matter of decency rather than secrecy.

[Drew]

I get a fair amount of information from a lot of sources, but it is not up to me to spread that information further, because it is not my intellectual property.
I leave it to those sources to decide if, when and how much they want to reveal. I think it is a matter of decency rather than secrecy.That's a set of morals the world could learn (or at least remember) a thing or two from.

[kel]

That's a set of morals the world could learn (or at least remember) a thing or two from.

Yes and no. While I respect Frits position I personally feel information can be referenced and shared (if the information is made available publicly) as long as appropriate credit is given to source and author. The world would be so dull and uneducated if we couldn’t quote great people.
Hopefully no lawsuits are to follow :dodge:

[husaberg]

I get a fair amount of information from a lot of sources, but it is not up to me to spread that information further, because it is not my intellectual property.
I leave it to those sources to decide if, when and how much they want to reveal. I think it is a matter of decency rather than secrecy.


Yes and no. While I respect Frits position I personally feel information can be referenced and shared (if the information is made available publicly) as long as appropriate credit is given to source and author. The world would be so dull and uneducated if we couldn’t quote great people.
Hopefully no lawsuits are to follow :dodge:

it's almost impossible to disagree with Frits on this one.
Richard has done (I guess a fair amount) of experimenting to come up with a way to seal a pipe so weather he (Richard) chooses to share the info (I hope he does) its entirely up to Richard. For all the information that is shared on the forums is because people have chosen to share it in the first place.... For that we owe an eternal gratitude to MR Thiel and MR Overmars and many others.

My wish list includes a complete 3d model of the Aprillia cylinder so we could all study it in great detail.
Now that would be a treat. I wonder if that is possible.......

Kel if there is to be a lawsuit it will be for the guy that has posted 100's copyrighted articles for public consumption.......But it would be a hard ask as most of it is out of print.....Plus i can outrun Kim Dotcom at least.......

[RAW]

To all
Perhaps I need to clarify what I meant,
The pipe information is freely displayed upon another forum by Richard, therefore it has been placed into the public domain and as such I have then thought it would no longer have been seen as a secret
To this i assumed as we are all assisting each other if and when possible that when asked we would freely be happy to converse this already published knowledge.

However given the subsequent posts I also have to understand that Richard did not place this information upon this forum and as such perhaps Frits your lack of sharing when asked directly can be understood

[wobbly]

We dont need a 3D model of Aprilias cylinder, all the relevant "secrets "are available in 2D drawings off various sources on the net.
I have applied most of them to various projects that have nothing to do with what Jan Thiel was trying to achieve.
But the ideas behind the tricks work in every case, for the same reason they worked initially.
Best example is the big radius on the transfer duct entry,where it begins at the bore edge.
There were several pics of this all over the place,and I can tell you with absolute surety, if you didnt see what was happening - and havnt got this in your cylinder,you are loosing Hp - simple.
We have 20 more little examples like this - as a wise man once said, look for the Devil ( or God ) in the details.

[Frits Overmars]

While I respect Frits position I personally feel information can be referenced and shared (if the information is made available publicly)
...The pipe information is freely displayed upon another forum by Richard, therefore it has been placed into the public domain and as such I have then thought it would no longer have been seen as a secret
......However given the subsequent posts I also have to understand that Richard did not place this information upon this forum and as such perhaps Frits your lack of sharing when asked directly can be understood
Anything I learn via any open forum can freely be passed on, and I would be happy to do so. But I do not always remember whether the information that I received, came to me via an open forum, a restricted forum, or verbal.
If you ask for a specific piece of information, I would have to check all open forums to see if it was already posted somewhere, before I can decide to pass it on.
See my problem?

[RAW]

Anything I learn via any open forum can freely be passed on, and I would be happy to do so. But I do not always remember whether the information that I received, came to me via an open forum, a restricted forum, or verbal.
If you ask for a specific piece of information, I would have to check all open forums to see if it was already posted somewhere, before I can decide to pass it on.
See my problem?

Thanks Frits,
I surely can understand this given the so far discovered forum sites of which you appear upon, I would not have conceived your dilemma without you explaining it so, having thought about it now I wonder how this slipped past me
I am greatfull for you much valued assistance, to me personally and for all the many you have and I'm sure will continue to drive forward in the pursuit of perfection

Cheers

[TZ350]

we just downloaded a free dyno program called "Simple dyno"

https://sites.google.com/site/simpledyno/

It's limited but when setup is very repeatable ... the HP levels are right the power curve just looks funny because it is reading drum torque and HP rather than motor

Some pictures from the dyno sight, dynos for small radio controlled race cars, looks fun.

[Pumba]

Liking the design of the dirt bike one above. Simple cradle for the drum, a beam to sit the bike on, could be easily made to dissemble and be moved. Or stored away in the corner of the shed when not in use.

Only worry would be is it solid enough to stop it moving round while you were using it.

[crazy man]

Liking the design of the dirt bike one above. Simple cradle for the drum, a beam to sit the bike on, could be easily made to dissemble and be moved. Or stored away in the corner of the shed when not in use.

Only worry would be is it solid enough to stop it moving round while you were using it.they are small bearing on in for alot of mass:eek:

[husaberg]

Can anyone add something about Des Barry, the bike or both.
70hp on Std carbs from a air-cooled RD350 must have been fairly special then. (1983)


British F2 1985 1st Des Barry Yamaha 350

Wiki gives the results for the world F1 and F2.
1984 F2 9th=
1985 F1 10th & F2 12th.
1986 F2 7th,
googling i also found some mention of a spondon framed RZ500 being raced later.http://www.rzrd500.com/500phpBB2/viewtopic.php?t=9619&sid=0385a10812abee8e861b5f74881599a1

Oh it looks like Barry lives in the UK and is some sort of motivational speacker or such like.




We dont need a 3D model of Aprilias cylinder, all the relevant "secrets "are available in 2D drawings off various sources on the net.
I have applied most of them to various projects that have nothing to do with what Jan Thiel was trying to achieve.
But the ideas behind the tricks work in every case, for the same reason they worked initially.
Best example is the big radius on the transfer duct entry,where it begins at the bore edge.
There were several pics of this all over the place,and I can tell you with absolute surety, if you didnt see what was happening - and havnt got this in your cylinder,you are loosing Hp - simple.
We have 20 more little examples like this - as a wise man once said, look for the Devil ( or God ) in the details.

I know not all the tricks that you do Wob hence the need (ok want) for 3D. all the pic i have seen are Seemingly originally from Frits files or have i missed some.

[TZ350]

Good weather and a good turnout for the practice day at Mt Welly.

273019

With Kel still unable to ride Cotswold offered to chance his arm and take the Beast for a trot.

After a few small changes Cotswold looked to be getting to grips with the animal and enjoying himself and happily the Beast kept going all day, so a bit of progress in the reliability stakes.

The next step is the first round of the North Island series and Hampton.

[cotswold]

[QUOTE=TZ350;1130431077]Good weather and a good turnout for the practice day at Mt Welly.

273019

The 1st thing that comes to mind is the beast is fast. After riding FXRs for the past couple of years I need to learn how to pilot a 2 stroke again and struggled to get on the pipe out of some corners ( the infield and onto the straight )
Tee Zee was not sure the carburetion was correct and that may have been a factor as well, we did not play with it as a new carb is imminent and it was running well enough for a practice day.
All in all it was a good hit up with no dramas (which is how I like it)

[kel]

I need to learn how to pilot a 2 stroke again and struggled to get on the pipe out of some corners ( the infield and onto the straight )

Change down in the transition to the final corner, just using the clutch wont get you back onto the power quick enough. Slight touch of clutch coming out of the infield, you'll know if you give it too much!

[cotswold]

Change down in the transition to the final corner, just using the clutch wont get you back onto the power quick enough. Slight touch of clutch coming out of the infield, you'll know if you give it too much!

Thanks Kel

[chrisc]

It sure is quick! It was great to follow your line for a while Tim, I felt a lot faster after doing so.

[Frits Overmars]

[QUOTE=TZ350;1130431077]....I need to learn how to pilot a 2 stroke againIzze very simple: ride it like you just stole it.

[husaberg]

Izze very simple: ride it like you just stole it.

Question do what does the float set up look like on a carb from a RSW. Is it a conventional hinged float set up? (Like a ballcock)
Or more like a floating post?(like Wob mentioned earlier he made for the BSL to counter the fuel surging with the rearwards mounted carbs) i can imagine all sorts of carburation issues on long left and right hand corner, so i am assuming it was a sliding post set up? Or are i worrying about stuff that doesn't actually occur?

[andrew a]

Great to see that it ran for the day but my thoughts are if you take it to HD with no air box your looking for trouble. Good work Rob and the team.

[Leed]

.
.
auto... HONDA CR/RC...
"RC250MA motocross equipped with the "HFT", won the series championship in the second year of the All-Japan Motocross Championship racing in 1991. The ultra-high pressure, "HFT" maintained by the electronic control to obtain intelligence and high efficiency is the potential has been proven in combat that race yet."

"1991 was also the last year for Mugen in Motocross as they decided to focus on car racing instead. Honda had two automatics in the 250 class that year ... one was a full works bike and one was more 'production' based. The full works automatic bike won the series, while the 'production' based bike did win one round. The bike was awesome to see race and would shift based on the load felt by the motor ... the bike was always on the pipe.

Eric Geboers rode the works automatic during practice for the 1991 Tokyo Supercross, but decided not to race it. I was in the practice group with the rest of the Japanese 250 guys and got to watch Goboers take his laps (while standing next to the big triple). Geboers hit the triple and did a huge endo .. he was going right over the bars and it was ugly .. the bike was nearly vertically pointing straight down at the ground. Geboers pinned the throttle and the bike went braaapbraaapbraaap while automatically up-shifting through the gears. The gyro of the rapidly accelerating rear wheel literally pulled the back of the bike down and he landed it perfectly. I think that was his last lap on the bike, but it was simply unbelievable to see and I will never forget it. " quote RbR

I recall some experiments with it in the AMA circuit
and 20 years later the Zero shift system on the Honda RC212V

http://4.bp.blogspot.com/-tzKqlZ2L6Ns/UGSL56tir8I/AAAAAAAADOY/H1pp-9Sgp4Y/s1600/ra2.JPG

sparkplugs...
why do we have to pay over 100% markups on plugs in NZ?
and if I buy the OEM iridiums plugs for a car I could expect to pay NZ$160 for a 4 set (from a dealer)
so I fork out $20+ for iridiums on a bike, when I can import from the UK ($12) or Japan (for less than $10 each)

I can't comment on whether the ultimate power is obtained from the NGK variety but I think the Denso are silightly higher build quality, and in terms of presentation - the Denso electrode protectors in the packaging are plastic tubes rather than NGK's cardboard - 0.4mm dia electrodes are super fine

[F5 Dave]

.
.. . but I think the Denso are silightly higher build quality, and in terms of presentation - the Denso electrode protectors in the packaging are plastic tubes rather than NGK's cardboard - 0.4mm dia electrodes are super fine
um, trivial issue, the NGK used to use plastic but went to Cardboard. I think you will find if was for appearing more environmentally friendly. Even the Japanese.

[Frits Overmars]

.....and 20 years later the Zero shift system on the Honda RC212VHonda has never used the Zeroshift system; the seamless shift system on the RC212V is fundamentally different: http://www.pit-lane.biz/t1720p71-motogp-dual-clutch-transmission-non-seamless

[twotempi]

If an Aprilia 125 GP bike has the frame number RSR 129410 what year does this relate to ?? Does the "94" in the code mean it is a 1994 model ??

thanks

[2T Institute]

Question do what does the float set up look like on a carb from a RSW. Is it a conventional hinged float set up? (Like a ballcock)
Or more like a floating post?(like Wob mentioned earlier he made for the BSL to counter the fuel surging with the rearwards mounted carbs) i can imagine all sorts of carburation issues on long left and right hand corner, so i am assuming it was a sliding post set up? Or are i worrying about stuff that doesn't actually occur?

Have a 39.5 Delorto VHSC and seen a few VHSD's at the GP and they looked conventional hinged floats. They do have shallow bowls though

[husaberg]

If an Aprilia 125 GP bike has the frame number RSR 129410 what year does this relate to ?? Does the "94" in the code mean it is a 1994 model ??

thanks

A while back Frits posted the tech manuals which i guess may answer your question.

Thanks, Mental; everything seems to be fine now. So here they are again:
http://www.kiwibiker.co.nz/manual/Aprilia-1.zip (http://www.kiwibiker.co.nz/manual/Aprilia-1.zip) (6.8 MB)
http://www.kiwibiker.co.nz/manual/Aprilia-2.zip (http://www.kiwibiker.co.nz/manual/Aprilia-2.zip) (8.3 MB)
http://www.kiwibiker.co.nz/manual/Aprilia-3.zip (http://www.kiwibiker.co.nz/manual/Aprilia-3.zip) (9.2 MB)
http://www.kiwibiker.co.nz/manual/Aprilia-4.zip (http://www.kiwibiker.co.nz/manual/Aprilia-4.zip) (7.2 MB)
http://www.kiwibiker.co.nz/manual/Aprilia-5.zip (http://www.kiwibiker.co.nz/manual/Aprilia-5.zip) (5.6 MB)

Have a 39.5 Delorto VHSC and seen a few VHSD's at the GP and they looked conventional hinged floats. They do have shallow bowls though thanks i often wonder about problems that probably exist only in my head i guess (must be getting old)

.auto... HONDA CR/RC...
"RC250MA motocross equipped with the "HFT", won the series championship in the second year of the All-Japan Motocross Championship racing in 1991. The ultra-high pressure, "HFT" maintained by the electronic control to obtain intelligence and high efficiency is the potential has been proven in combat that race yet.""1991 was also the last year for Mugen in Motocross as they decided to focus on car racing instead. Honda had two automatics in the 250 class that year ... one was a full works bike and one was more 'production' based. The full works automatic bike won the series, while the 'production' based bike did win one round. The bike was awesome to see race and would shift based on the load felt by the motor ... the bike was always on the pipe.
it says it is a CTV in the pic like the Monotrak and a lot of scooters and the DAF car (Frits will relate to that i guess)but Honda seem to have overcomplicated it in a way that i don't understand why.GEE Honda a belt and pulley would be neater less parts etc.(Whoops its actually :scratch:a comparsion so bum slapfor me i better brush up on my Japanese.
http://en.wikipedia.org/wiki/Human_Friendly_Transmission
http://upload.wikimedia.org/wikipedia/commons/d/df/Swashplate_anim_metal.gifhttp://thekneeslider.com/images/hondadn01hft2.jpghttp://thekneeslider.com/images/hondadn01hft.jpg
Oh it is a Swash plate transmision (not that i know WTF that is)Hindsight i guess the moving rods control the oil flow?

[ Characteristics of the HFT http://http://thekneeslider.com/archives/2007/10/04/honda-dn-01-human-friendly-transmission-hft/ (http://thekneeslider.com/archives/2007/10/04/honda-dn-01-human-friendly-transmission-hft/)]
A transmission system with a wide range of functions in a single unit, the HFT is a compact and highly efficient infinitely variable transmission system encompassing functions for starting, power transmission and shifting, all on a single shaft. The basic configuration of the system consists of an oil pump for converting engine power into hydraulic pressure, and an oil motor for converting the hydraulic pressure back into power for output. Both are made up of multiple pistons, a distributor valve and a swash plate for piston operation, while the cylinders are integrated into the output shaft, forming the characteristic structure of the HFT.The HFT also features the world’s first* lockup mechanism for an infinitely variable hydraulic mechanical transmission. When cruising, this lockup mechanism works to minimize transmission efficiency losses, contributing to improved fuel economy.

- Soichiro Honda becomes interested in hydrostatic drives in the early 1950s.
- Honda licenses use of a patent for a machine-tool hydrostatic drive.
- Honda debuts the Juno in 1962, a Japanese-market scooter with hydraulic drive. A mechanically actuated system shifted gears via the left hand grip.
- The Honda RC250 factory motocross bike with an automatic transmission undergoes testing in the late 1980s.
- The Honda RC250MA motocrosser competed with the HFT in the 1990 all-Japan MX championship.
- The Honda Fourtrax Foreman Rubicon debuts in 2001 with a new-and-improved HFT.
- The 2008 DN-01 and its HFT are introduced in Europe
The huge advantage i can see is that you can use engine braking.
Human Friendly Transmission used on the Fourtrax rubicon and the DN01 or what ever its called.
http://i.imgur.com/9TFpV.gif<img src="http://4.bp.blogspot.com/-tzKqlZ2L6Ns/UGSL56tir8I/AAAAAAAADOY/H1pp-9Sgp4Y/s1600/ra2.JPG" width="540px"/>

.
Eric Geboers rode the works automatic during practice for the 1991 Tokyo Supercross, but decided not to race it. I was in the practice group with the rest of the Japanese 250 guys and got to watch Goboers take his laps (while standing next to the big triple). Geboers hit the triple and did a huge endo .. he was going right over the bars and it was ugly .. the bike was nearly vertically pointing straight down at the ground. Geboers pinned the throttle and the bike went braaapbraaapbraaap while automatically up-shifting through the gears. The gyro of the rapidly accelerating rear wheel literally pulled the back of the bike down and he landed it perfectly. I think that was his last lap on the bike, but it was simply unbelievable to see and I will never forget it. " quote RbR
The latest husaberg 4 smoke with the back to front upside down engine reportedly does interesting thing in the air (not sure of the engine rotation direction)

.sparkplugs...
why do we have to pay over 100% markups on plugs in NZ?
and if I buy the OEM iridiums plugs for a car I could expect to pay NZ$160 for a 4 set (from a dealer)
so I fork out $20+ for iridiums on a bike, when I can import from the UK ($12) or Japan (for less than $10 each)
Scale of our market unfortunately. they sell a lot more overseas.I tried to get hold of a shorty iridium for the CR500/250 Darbis allegedly told the big short there was no such thing. (could have been BS from the dealer though)

[dinamik2t]

Here's an exploded view of the VHSG : http://www.dellorto.co.uk/images/parts/VHSDDIAG.PDF

its float

http://www.dellorto.co.uk/images/parts/15760.jpg


And here's the VHTC :

273065273066

[Frits Overmars]

Question do what does the float set up look like on a carb from a RSW. Is it a conventional hinged float set up? (Like a ballcock) Or more like a floating post?Both the RSW and RSA carbs have pole-dancing float bodies.

[husaberg]

:eek5:
Here's an exploded view of the VHSG : http://www.dellorto.co.uk/images/parts/VHSDDIAG.PDF

its float

And here's the VHTC :
.


Both the RSW and RSA carbs have pole-dancing float bodies.

Thanks Frits and Dinamik.... So was my imagined lean out and over-enrichen from the bike leaning over a real issue. Or is it just a coincidence that they have pole floats?( i just finished looking at the pic Dinamik posted and was going to scold Lozza for missing it. but in hindsight in total fairness i guess was question was loosely framed

[twotempi]

A while back Frits posted the tech manuals which i guess may answer your question.

Have had a previous good look through this info but it only goes back to 2010 unless I missed it ( which is quite possible).

I think that the bike is a 1994 - 1996 ish model so would like to know what it is for elligibity reasons.

[husaberg]

A while back Frits posted the tech manuals which i guess may answer your question.

Have had a previous good look through this info but it only goes back to 2010 unless I missed it ( which is quite possible).

I think that the bike is a 1994 - 1996 ish model so would like to know what it is for elligibity reasons.

Is it the one that was for sale a while back...Yellow and expensive.........

[Ocean1]

Oh it is a Swash plate transmision (not that i know WTF that is)Hindsight i guess the moving rods control the oil flow?

That's not a good graphic. It's a very well establiched hydraulic mechanism, variable stroke axial piston beastie.... here:

<iframe width="420" height="315" src="http://www.youtube.com/embed/CksSdoG0w44" frameborder="0" allowfullscreen></iframe>

Very cute, not as efficient as conventional gears or chains but if the gains in maintaining a constant optimal ratio with no shifts adds up it makes sense.

Edit: that's a pressure compensated one, will ramp up displacement until it reaches a preset pressure then ramp down to zero. An auto transmission version can ramp up until a target torque is reached then maintain displacement.

[husaberg]

That's not a good graphic. It's a very well establiched hydraulic mechanism, variable stroke axial piston beastie.... here:

Very cute, not as efficient as conventional gears or chains but if the gains in maintaining a constant optimal ratio with no shifts adds up it makes sense.

Edit: that's a pressure compensated one, will ramp up displacement until it reaches a preset pressure then ramp down to zero. An auto transmission version can ramp up until a target torque is reached then maintain displacement.

So the faster it goes the more oil it pumps up to a certain level then maintains it. So couldn't a simple plunger pump (like a renown) and a regulator bypass accomplish the same without the additional fuss. (Probably missed the point i guess)
I have to say i still like the double expanding pulleys or the husky main centrifugal then four separate centrifugal dog clutches better other than the overun and non lock up of course.
Oh Frits you never mentioned the lever that you trip to start the Husky beasty to isolate the clutch i guess ...

[Ocean1]

So the faster it goes the more oil it pumps up to a certain level then maintains it.

No, the displacement is controlled by the swash plate, not (only) shaft rev's. When the plate is perpendicular to the main shaft displacement is zero, as the plate angle increases the pistons begin to stroke more.

In that video the plate angle is controlled by oil pressure acting against a spring, more pressure = less displacement, it hunts for a set pressure.

A variable transmission version can have the plate controlled by several variables; rpm, torque, throttle position, road speed etc etc. It will displace from zero to it's maximum capacity depending on those inputs. Perfect ratio for each set of variables, continuously. Energy efficiency maybe 85% against multiple gears at about 95%.

[speedpro]

Talking transmissions - what would the efficiency be of a CVT transmission as fitted to a typical jap scooter such as my Yamaha NXC125? I'm suspecting it's low due to losses at the belt to pulley interface but since it provides the ideal engine torque dependant on throttle and speed it makes up for it. On the dyno when horsepower is mapped against road speed there is a lot of area under the graph though the measured power is pretty modest for the capacity.

[husaberg]

http://antholonet.com/EngineersCars/DAF/daf55Transmission.jpg
http://antholonet.com/EngineersCars/DAF/daf.html
To allow fully automatic operation a centrifugal clutch on each belt engaged smoothly when accelerating from a stop. While moving, the pressure applied to the first pair of conical disks was controlled by the manifold vacuum and engine rpm, thus automatically ensuring the appropriate ratio for any condition. Reverse was engaged before the differential, allowing the DAF to be driven just as fast in reverse as it did going forwards! The transmission lever had only three positions: Forward, Neutral and Reverse. There was also a button which locked the transmission into a particular gear ratio which allowed engine braking for driving downhill.


DAF's innovative Variomatic Transmission, continued to be developed, eventually being used by Nissan and others. It was even developed enough to be used in a prototype Williams F1 car. However, the prototype system proved so efficient that it was quickly banned from F1 racing.

[Frits Overmars]

To allow fully automatic operation a centrifugal clutch on each belt engaged smoothly when accelerating from a stop. While moving, the pressure applied to the first pair of conical disks was controlled by the manifold vacuum and engine rpm, thus automatically ensuring the appropriate ratio for any condition.....There was also a button which locked the transmission into a particular gear ratio which allowed engine braking for driving downhill. Nope. That button didn't lock the transmission ratio. It cut off the manifold vacuum signal, so revs did not drop when you closed the throttle, and the transmission ratio remained optimal. I have owned two DAFs and I always drove with the button in that position because it gave a better pick-up.

DAF's innovative Variomatic Transmission, continued to be developed, eventually being used by Nissan and others. It was even developed enough to be used in a prototype Williams F1 car. However, the prototype system proved so efficient that it was quickly banned from F1 racing. It was primarily banned because of its sound. People want to hear engine revs go up and down as drivers go through the gears. The Williams-F1, driven by young David Coulthard, sounded like a horn going round the track, always emitting the same tone. The FIA did not like that.

[husaberg]

Nope. That button didn't lock the transmission ratio. It cut off the manifold vacuum signal, so revs did not drop when you closed the throttle, and the transmission ratio remained optimal. I have owned two DAFs and I always drove with the button in that position because it gave a better pick-up.
It was primarily banned because of its sound. People want to hear engine revs go up and down as drivers go through the gears. The Williams-F1, driven by young David Coulthard, sounded like a horn going round the track, always emitting the same tone. The FIA did not like that.

http://www.ret-monitor.com/articles/1104/transmission/I asked Boulanger his opinion about the ‘arms race’ that CVT would have brought to Formula One. Would everyone have had to develop CVT, had it not been banned by the FIA? “Yes - not because the public would have liked it, but they would have been forced into it,” he says.
Despite the fact that Boulanger believes that the public would have hated CVT in Formula One, such was its potential advantage that everyone would have been forced to follow because the penalty of not doing so would be so damaging. In the next issue of RET-Monitor we will look at some other aspects of this fascinating project.

http://www.ret-monitor.com/articles/1187/formula-one-cvt-part-2/Williams developed in conjunction with Van Doorn in the early 1990s, and spoke to engineer Arnaud Boulanger who was involved with the project...The nature of the relationship between Williams and Van Doorn was one of exclusivity. Had the CVT not been banned, the route to development of a successful system for other teams would have been made harder by this deal.
We can see that, beyond the initial successful test where the concept was proven to work and to be very effective, there would have been a tremendous amount of work to do in order to make any car using such a system race-worthy. In fact, had the FIA not banned the system - and had Williams and Renault carried out the required work - their position of dominance would have been absolutely unassailable, and it could have changed Formula One for a long time.

Have you ever heard a CVT car drive by? I heard DC testing the Williams F1 CVT gearbox and it was bloody infuriating. The engine never changes speed because the gearbox handles all of that. The car just made this horrible monotone sound the whole way around the track. Nobody would be able to take the sound of 20 F1 cars that are make the same tone. You couldn't tell if they were speeding up or slowing down. It would be horrible.

http://www.youtube.com/watch?feature=player_detailpage&v=x3UpBKXMRto

This point was well understood by car engineers outside of Williams long before 1993. One solution was to do away with a conventional gearbox and instead use a system of pulleys to adapt the engine’s power in line with what the driver required.
The system – continuously (or “continually”) variable transmission – existed in various different forms. DAF had produced a road car in 1958 called the 600 (or “A-Type”) which featured a “Variomatic” gearbox – which was essentially a CVT.
The problem for using such technology in racing cars was the difficulty of finding a strong enough belt to transit the power from an F1 engine.
In 1993 Williams cracked it and David Coulthard tested the car on a wet July day at Pembrey in Wales. It was later driven by touring car racer Alain Menu (his Renault 19 race car was prepared by Williams at the time).
At first it was feared that a ban on electronically controlled gearboxes would do away with the CVT before it could race. But in the end the FIA came up with something much more direct to get rid of it.
They stipulated that, from 1994, F1 cars had to have between four and seven fixed gears – and for good measure added a sub-clause specifically banning CVT.
Williams’ CVT car sounded revolutionarily different to contemporary (and modern) F1 cars because of the different way it used the engine. Instead of the revs rising and falling with each corner they remaining constant through each bend – a wholly unusual sound for spectators.
There was also speculation that it had instantly proved several seconds per lap quicker than the conventional Williams – which was already streets ahead of its rivals.

http://histomobile.com/dvd_histomobile/usa/tech/83-2.htmMeanwhile, another concept of mechanical CVT became widespread: the V-belt and conical pulleys of variable effective diameter. Patented in 1897 in the USA by H. C Spaulding, this device was initially used on machine tools, then as from the Fifties on motor cycles (Mobymatic of Mobylette) and scooters (DKW Hobby) as well as for the drive of centrifugal compressors (Mac Culloch VS 57). It was then popularized by DAF under the name Variomatic in 1958, with a ratio span of 3.72. This transmission remained in production until 1990 for the Volvo 340 with the Renault 1.4 L engine – in spite of a longevity of the two belts hardly reaching 40000 km. Working in the open, it was also fitted successfully on two Brabham-Cosworth of Formula 3 which gained 2 victories in 1967. It had been possible to tune their engines to extract the maximum of power without being concerned about their torque back-up. Some F3 Tecno were then also equipped with such a CVT.
This system has been further sophisticated lately since it is able today to transmit torques of more than 350 Nm, thanks to a single chain or metal belt working in oil inside a casing. Since 1987, the fragile rubber belts had seen the competition of a metal version mass-produced by Van Doorne Transmissie (VDT) and composed of two parallel endless steel rings enclosing 300 to 400 "push plates". The sides of these push plates, in V at the angle of the pulleys flanks, ensure the contact with them. The push plates press against each other while being constrained to follow the path dictated by the rings. That's why this belt is known as a "push-belt". A Formula 1Williams FW15C using this new type of belt would have semi-officially set a new elapsed-time track record at Silverstone in 1993[1 ]. The CVT were then banished by the FIA for the following year.
Williams-Renault FW 15 C - CVT
In Europe, the preconceived and prevalent idea remains that automatic transmissions are intended for the quiet and slow driving characteristic of the elderly and not so sporty guys, although the opposite was clearly shown in racing by JimHall's Chapparals in the 60's and by some other racing drivers, amongst them the engineer and great journalist Paul Frère.
In order to give a better image of the product by launching it again on the race tracks, Emery Hendriks of Van Doorne Transmissions contacted in 1991 Patrick Head, technical director of the Williams Formula 1 team. After a simple gentleman's agreement, it was decided to go forward. VDT built a test bench able to handle CVT powertrain prototypes with Formula 1 engines of 800 kW and more. The transmission was planned for a ratio span of 2.5 and a lifespan of 4 hours. Its development took one and half year, Williams taking care of the design and manufacturing of the casings, gears and conventional starting clutch controlled by the usual pedal. A sophisticated electronic control system was conceived in collaboration. Several small oil pumps were set, each one affected to a specific task. This made it possible to increase the transmission efficiency up to 95% instead of the much lower percentage of the marketed versions. A car was ready in 1993 and entrusted to David Coulthard, then development driver at Williams.
The results were promising, accelerations being uninterrupted and the maximum power permanently available. Moreover the pilot had his two feet available to accelerate with one and to brake with the other (advantage inherent to every automatic transmission as soon as the driver is accustomed to this practice) and its attention could be focused on driving itself. It was possible for him to adjust the engine revs according to the needed power, in fact to reduce the rpm if his advance on the other competitors would have been sufficient.
Being given that a CVT contains intrinsically all the conceivable ratios, it wouldn't have been necessary any more to transport for each race some 600 kg of gears in order to adapt the transmission ratios to the track's characteristics. However, the FIA banned any driving assistance such as ABS, ESP and CVT, this probably in a bid to maintain the spectacle and the popularity of the Grand-Prix. The Williams FW 15C then finishes quietly her days in a museum and documentation relative to these developments takes the dust in the drawers of the two companies.
Sources:
Yamaguchi Jack: CVT' S rapid expansion, Automotive Engineering, March 1996
Without author's name: CVT, Transmission à Variation Continue ou Transmission Viable Commercialement
in 'Ingénieurs de l’Automobile N° 690, Juin-Juillet 1994'

whether true or not it makes for a great conspiracy theory. The noise of course is constantly mentioned but so is a lap time advantage wheater this would have been the case and weather the engines could have handled it we will never know i guess.
The last bit quoted seems legitimate as the sources are quoted and credited also the williams active suspension was banned at around the same time.
the 95% effeciency claim is incredible......

http://www.youtube.com/watch?feature=player_detailpage&v=uCEvBGT8twM#t=26s
From Memory Honda does this around the other way(below).I cant remember why

http://www.youtube.com/watch?v=MhFK5gfAGpM&feature=player_detailpage#t=76s
one with chain, ban those pesky belts
http://www.youtube.com/watch?feature=player_detailpage&v=5JbnDXw-0pM#t=1s
Well worth watching power of friction

[2T Institute]

I have owned two DAFs and I always drove with the button in

Which number were you Frits :laugh: Jeez this was big action back in the day probably rated it's nuts off on Hilversum 2


http://www.youtube.com/watch?v=S7ipFApsFec&feature=related

[husaberg]

I have always wondered about this with pit dump tracks and trains but thought more electrical storage.
Kers
the real deal is here.
http://strumors.automobilemag.com/files/2011/05/volvo-flywheel-kers-diagram-1-623x389.jpg
http://rumors.automobilemag.com/volvo-developing-flywheel-hybrid-could-boost-economy-20-percent-49623.html

Hybrid flywheel energy storage got off to a bit of a shaky start in Formula 1 back in 2009, but the technology is gaining ground outside the motorsports arena in production cars, utility companies, and – now – it’s found its way into bicycles!

The bike you see here has been rigged up with a 15 lb. automotive flywheel that’s mated to a CVT, which allows the rear wheel to transfer kinetic energy to the flywheel under “braking”, effectively slowing the bike down. Once the cyclist is ready to pick up speed again, the CVT is shifted the other way, and the spinning mass of the flywheel “boosts” the rider’s legs and provides forward motion – just like the flywheel KERS systems proposed by Williams F1 (which provides flywheel hybrid tech to Porsche) and Volvo.It’s a great concept that, once seen, is easy to understand. Check out some close-up schematics and installation photos (below), and see for yourself!
I am not sure of how easy the bike would maneuver though with the 15 lb spinning mass....plus the real deal spins in a vacume as well but intersting to me anyway..
<img src="http://c1gas2org.wpengine.netdna-cdn.com/files/2011/08/flybike_main.jpg" width="385px"/><img src="http://gas2.org/files/2011/08/flybike_2.jpg" width="340px"/><img src="http://gas2.org/files/2011/08/flybike_1.jpg" width="405px"/>
<center>
Also Frits was i close with the reason for the post floats with the RV Aprillia or miles off

[TZ350]

OK ... it might be 4-stroke but its an interesting story on setting up and using a Mega Squirt fuel injection system.

http://www.madhu.com/content/Main/FuelInjection

and Co2 powered Shift kit.

http://www.biperformance.ca/cShiftFXDrag.html

[husaberg]

Burt Munro

A tenacious bugger if ever there was one.

Here is an except form the book that George Begg wrote.
George was certainly a character himself..I sincerely think he wouldn't have minded me posting a wee bit of it.
I should ask arround and see if there was a second print run ever done.
That can be your job Greg and Warwick.

"The Munro Paddle dyno"

[Buckets4Me]

Which number were you Frits :laugh: Jeez this was big action back in the day probably rated it's nuts off on Hilversum 2


http://www.youtube.com/watch?v=S7ipFApsFec&feature=related

I'm sure I saw TZ's 100m/h simca in there. The red white and blue one with a dinosaur on the side :yes:

[wax]

cvt is so smooth onto the power that you can get on the gas earlier. we constantly pull motorbikes out of the corners on our 50cc scooters

[Grumph]

Burt Munro

A tenacious bugger if ever there was one.

Here is an except form the book that George Begg wrote.
George was certainly a character himself..I sincerely think he wouldn't have minded me posting a wee bit of it.
I should ask arround and see if there was a second print run ever done.
That can be your job Greg and Warwick.

"The Munro Paddle dyno"

As far as i know only the one print run....Hannah's book came out after George's one and was better marketed.
George would have asked for a reprint fee for your post.......

[husaberg]

As far as i know only the one print run....Hannah's book came out after George's one and was better marketed.
George would have asked for a reprint fee for your post.......

I'd have been beggered if he had of...:facepalm: Nah i would have reminded him that i had brought two of his loaders and roll frames over the years and sold the both loaders for more than i payed for the tractors....then i would have asked for a commission fee.

George for those you don't know who he was made Begg attachments after hours they made F5000 cars. George and raced a brace of Manx Nortons including at the IOM.
He was one of the driving forces behind the classic movement here in the south. Rarely missed a race meeting in the south Island (even when he moved to Aussie.)
He was a larger than life character both figuratively and literally. His voice and laugh could be heard all over the pits.

[wobbly]

Not only did Begg make F5000 cars the guys who actually did the work ( Fred McLean and Peter Pinion ) also
built race frames for bikes.
They did TZ350s and one with a TZ500 or 750
Im building a replica ( modified after some FEA work ) Frepin 350 now, for Discombe to race at Philip Island and I also have the original 500 frame.
Here is a pic of the 350 frame in front of a new 400 - F3 bike.
Anyone know anything about the 500 - I believe a John McLaclan rode it in the 80s.

[F5 Dave]

So I think Aussies run pre 80 rather than pre 82 like we do. I was investigating a mates bike & I think is was an Aussie P&R in square section ally, but I rang them & sadly it was 83. Originally designed for a TZ250/350 it was fitted with a 256 Rotax, pity, one year crosses the line from competitive in 82 to nowhere in 89 a less covered class.

[wobbly]

Na the OZbergers run Post Classic Pre 82 Junior as we do, but like the poms the buggers allow late model TZ, 41mm forks on a TZ350.
We must run period only forks, so I have built up a set from 82 GS1100GK, the only production bike I can find with 41mm conventional forks from pre 82.
And using special SV650 legs the Doctor will be fitting GSXR Ohlins cartridges inside, as internals are free - that will teach them.
P&R did an alloy swingarm in period for the TZ350, so that is OK within the rules.

[Bert]

OK ... it might be 4-stroke but its an interesting story on setting up and using a Mega Squirt fuel injection system.

http://www.madhu.com/content/Main/FuelInjection


here's a two stroke injection project that I've following with interest (same motor as my tzr100):
http://www.125ccsportsbikes.com/forums/index.php?showtopic=63480&st=0

some other crazy sh!t:
http://www.youtube.com/watch?v=CzHX2m1ze8s&feature=share&list=UUfBcOly3Dw4iBpiDizddl2A



Not only did Begg make F5000 cars the guys who actually did the work ( Fred McLean and Peter Pinion ) also
built race frames for bikes.
They did TZ350s and one with a TZ500 or 750
Im building a replica ( modified after some FEA work ) Frepin 350 now, for Discombe to race at Philip Island and I also have the original 500 frame.
Here is a pic of the 350 frame in front of a new 400 - F3 bike.
Anyone know anything about the 500 - I believe a John McLaclan rode it in the 80s.

hummm it all starts making sense. a little bit of history (in the making again)....
Your F3-400 is looking great Wobbly

http://2stroker.createforumhosting.com/frepin-t3140-105.html

[husaberg]

Not only did Begg make F5000 cars the guys who actually did the work ( Fred McLean and Peter Pinion ) also
built race frames for bikes.
They did TZ350s and one with a TZ500 or 750
Im building a replica ( modified after some FEA work ) Frepin 350 now, for Discombe to race at Philip Island and I also have the original 500 frame.
Here is a pic of the 350 frame in front of a new 400 - F3 bike.
Anyone know anything about the 500 - I believe a John McLaclan rode it in the 80s.


Most of us here in the South Island would have seen and heard this unique New Zealand Home brewed special
(Both the frequency and the amplitude are pretty unforgettable)
But i guess it might be interesting to the northerners.
George Begg's factory/Workshop must have been an exciting place to be after hours what with the construction of the F5000 cars and Burt Munro dropping in to borrow the use of equipment and materials and with specials such as this.

i had posted this before.
The Begg workshop was obviously a hot bed of special building.

[Grumph]

Not only did Begg make F5000 cars the guys who actually did the work ( Fred McLean and Peter Pinion ) also
built race frames for bikes.
They did TZ350s and one with a TZ500 or 750
Im building a replica ( modified after some FEA work ) Frepin 350 now, for Discombe to race at Philip Island and I also have the original 500 frame.
Here is a pic of the 350 frame in front of a new 400 - F3 bike.
Anyone know anything about the 500 - I believe a John McLaclan rode it in the 80s.

I got asked about Frepin frames not long ago by a CAMS guy who wanted to build a replica. There used to be one hanging in the rafters at ChCh motorcycles -shop's gone now of course. i asked Lindsay Williamson who ran the place what happened to it. He reckons John White has it. He also reckons it is the 350 frame Fred modified to tale a 750...John Mclachlan doesn't ring a bell - PAUL Mclachlan does...
Paul is still around ChCh and apparently is keen to come out at next year's Wigram revival.
John White is here in ChCh - someone will know where - his son is heavily involved in D1 drifting.

[Grumph]

Na the OZbergers run Post Classic Pre 82 Junior as we do, but like the poms the buggers allow late model TZ, 41mm forks on a TZ350.
We must run period only forks, so I have built up a set from 82 GS1100GK, the only production bike I can find with 41mm conventional forks from pre 82.
And using special SV650 legs the Doctor will be fitting GSXR Ohlins cartridges inside, as internals are free - that will teach them.
P&R did an alloy swingarm in period for the TZ350, so that is OK within the rules.

welcome to the wierd & wonderful world of post classics wob....the Canadians let you use any conventional forks up to 41mm - but specify solid spoke mags for the pre 82 period.....i think the first Goldwings were 41mm too.
Looked at in world context our rules aren't too bad. Now enforcing them.....

[husaberg]

From memory (You would know better than me) Jon also did the stream-liner with the Britten motor as well as the Whitepower Ducati Replica F2 frames. But i am pretty sure he spelled It Jon though.



Na the OZbergers run Post Classic Pre 82 Junior as we do, but like the poms the buggers allow late model TZ, 41mm forks on a TZ350.
We must run period only forks, so I have built up a set from 82 GS1100GK, the only production bike I can find with 41mm conventional forks from pre 82.
And using special SV650 legs the Doctor will be fitting GSXR Ohlins cartridges inside, as internals are free - that will teach them.
P&R did an alloy swingarm in period for the TZ350, so that is OK within the rules.
good luck finding some..... never seen one in the flesh myself
41mm Kawasaki KZ-1300A1-A4 (79-82)

Below is the fork tube sizes and the stem sizes and Axel sizes for a lot of bikes.
For the taper roller bearing sizes go to the Sudco cattledog.

[Kickaha]

From memory (You would know better than me) Jon also did the stream-liner with the Britten motor as well as the Whitepower Ducati Replica F2 frames. But i am pretty sure he spelled It Jon though.

The streamliner that crashed out fairly early on in the record attempts

Stu Whyte used to do the replica TT2 frames (Whytech?), Jon was known for his rapid Trident

[husaberg]

The streamliner that crashed out fairly early on in the record attempts

Stu Whyte used to do the replica TT2 frames (Whytech?), Jon was known for his rapid Trident

oh whoops but the TTF2 were definitely originally Whytepower or whitepower even at the time the was a little provocative i can see why it was changed.
So was Jon's Trident the one with the inlet manifolds made from pushbike steering stems (Peugeot???) or was that someone else

[TZ350]

... my thoughts are if you take it to HD with no air box your looking for trouble.

Remembering Andrews suggestions at Taupo, for the last Mt Welly I recycled the plenum as an air box.

Its not so obvious but the carb is inside and the old plenum cavity acts as a spilt fuel catch tank and wind shield come small airbox.

It ran OK at the last race meeting but I havent dynoed this arrangement yet, hopefully I will get a chance to tomorrow night.

[wax]

here's a two stroke injection project that I've following with interest (same motor as my tzr100):
http://www.125ccsportsbikes.com/forums/index.php?showtopic=63480&st=0

some other crazy sh!t:
http://www.youtube.com/watch?v=CzHX2m1ze8s&feature=share&list=UUfBcOly3Dw4iBpiDizddl2A




hummm it all starts making sense. a little bit of history (in the making again)....
Your F3-400 is looking great Wobbly

http://2stroker.createforumhosting.com/frepin-t3140-105.html


They normally make about 15hp for a good 70cc scooter 12-13 hp is as low as they go. He manages to take a good cylinder and make it slower. you should have seen when he put the turbo on one. He got it down to about 8hp in the end.

[wobbly]

I knew about the GoldWing forks but apart from being Honda they are way heavy - didnt know about the big Kawa though ,thanks.
It may in fact be Paul McLachland or whatever - I am trying to confirm what engine was actually raced in the modified frame.
The basic engine is the same - just differing cylinders, but it would be good to know exactly what and who raced.
I have the frame, seat, fairing,tank,swingarm - but finding an engine isnt going to be easy.
There will be one floating around under a bench somewhere, as Trev sold his Bakker frame and 750 engine separated.
The mods are very agricultural, involving crushing tubes in a vise, and the main chassis tubes are already bent from excessive chain pull, but I intend "fixing "all that if I can find a powerplant.
I bought some mint GS1100 forks for 90USD, and new high tensile thin wall SV650 tubes from England for 80GBP as they were leftovers from ProTwins racing, just need
to arrange another mortgage to get Denis on the job at KSS.

[Grumph]

I knew about the GoldWing forks but apart from being Honda they are way heavy - didnt know about the big Kawa though ,thanks.
It may in fact be Paul McLachland or whatever - I am trying to confirm what engine was actually raced in the modified frame.
The basic engine is the same - just differing cylinders, but it would be good to know exactly what and who raced.
I have the frame, seat, fairing,tank,swingarm - but finding an engine isnt going to be easy.
There will be one floating around under a bench somewhere, as Trev sold his Bakker frame and 750 engine separated.
The mods are very agricultural, involving crushing tubes in a vise, and the main chassis tubes are already bent from excessive chain pull, but I intend "fixing "all that if I can find a powerplant.
I bought some mint GS1100 forks for 90USD, and new high tensile thin wall SV650 tubes from England for 80GBP as they were leftovers from ProTwins racing, just need
to arrange another mortgage to get Denis on the job at KSS.

Pretty sure if it was Paul's motor in the Frepin it was a 700. Memory says he put it all back into the TZ frame quite quickly and sold it.
The 350 Frepin frames were pretty marginal for strength/stiffness with a twin....
Sorry the Bakker got split...I remember Stu Avant fronting with it and admiring the workmanship.

[husaberg]

Left field but but Ceraini http://www.discovolantemoto.co.uk/suspension/classic-grand-prix-35mm-replica-ceriani-forks/prod_117.html
Rickman had 41mm forks. Made by (i think) Metal profiles) (Greeves now)
http://www.vintagebike.co.uk/wp-content/uploads/2010/09/rickman-enfield-interceptor-1-848x570.jpg
Might be a bit hard finding them though.no doubt someone make replicas.Marzochi probably as well too.
On Lawsons bike from the early 80's Rob Muzzy used to run police spec tubes. same outside dia but thicker id no one noticed.......

[wobbly]

As im replacing 35mm TZ forks with 41mm legs, im making them very thin wall in hi tensile tube.
Still way stronger than the bendy originals,along with fully adjustable cartridges to boot.

[RAW]

Hi all, Attached is some pictures of a late model TZ yamaha titanium GP 125/250 pipe. Can anyone explain what the part inside the pipe is.

Why is it there?
What is it called?
How does it work?

[husaberg]

Hi all, Attached is some pictures of a late model TZ yamaha titanium GP 125/250 pipe. Can anyone explain what the part inside the pipe is.

Why is it there?
What is it called?
How does it work?

Ten carrot actors.

follow the posts for the RGV500 version and pictures

Here's some pics of rgv500 cylinders and pipes...hhmmm...
http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=258136&stc=1&thumb=1&d=1329761342http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=258135&stc=1&thumb=1&d=1329761341http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=258134&stc=1&thumb=1&d=1329761339

When unleaded became mandatory in 98 most teams had a hell of a time keeping deto under control, having to run very rich and retarded.
The cylinders with the straighter pipes always gave alot more grief, untill a lowly dyno operator at Yamaha discovered that
when he stuck a large pressure probe into the header, the deto went away.
They managed to keep this secret for a couple of years but when teams like WCM got hold of the bikes, and left pipes lying about as you see in the pics,word soon got around.
The "things " intruding into the header take varying forms,but all do the same thing - the usually bottom "bent "pipes dont have the same issue, so dont need the so called deto buttons.
I have a couple somewhere from a Red Bull bike - I will pic them and post here .
.

[jasonu]

On Lawsons bike from the early 80's Rob Muzzy used to run police spec tubes. same outside dia but thicker id no one noticed.......

Muzzys have a fab shop here in Bend, Oregon. They make a lot of exhaust systems for bikes and quads. Not sure if they are still involved in interesting stuff anymore.

[TZ350]

... in case you are interested in "Jamathi's and other 50cc racers of the 60's" I've got a lot more photo material. Not just Jamathi, but also (in alphabetical order) Bultaco, DKW, Jawa, KTM, Kreidler, MZ, Ossa, Rumi, Suzuki and Yamaha, from 50 cc triples to 750 cc fours, all two-strokes. I've even got pictures of the works Hondas (both two- and foul-stroke).

Does anyone remember if these "other files" were ever downloded and where I can find them?

[husaberg]

TZ700/750 0W31 etc.
BIG Bang before it was fashionable........
<img src="http://raresportbikesforsale.com/wp-content/uploads/2010/09/1976-Yamaha-TZ750-Engine.png" height="360px"/><img src="http://www.cyclewack.com/thumbnail.php?pic=uplimg/img_A_101670_eaaf840606cada200add2680d7d72b43.jpg&w=500&sq=Y&b=Y" height="360px"/><img src="http://www.tz350.net/images/comp/tz750b_engine1.jpg" height="360px"/>

<img src="http://raresportbikesforsale.com/wp-content/uploads/2011/01/tz-engine-apart.jpg" height="250px"/><img src="http://raresportbikesforsale.com/wp-content/uploads/2011/01/tz-emgome.jpg" height="250px"/><img src="http://raresportbikesforsale.com/wp-content/uploads/2011/01/tz-engine-front.jpg" height="250px"/>

<img src="http://www.siegertyamaha.com/MotorradVerk/A83.jpg" height="285px"/><img src="http://t1.gstatic.com/images?q=tbn:ANd9GcRFJ0KgKL8i0NNRyQWv21VLW0pb1_pI0 bwNgeBGoQwxkIaAHvj1C0NI0wVR" height="285px"/><img src="http://t2.gstatic.com/images?q=tbn:ANd9GcQaR40CsSAcHBSOm6Pj8qkpr1CiRHibG Ikh01zHVJd2rmRVd30Ajv-qUBe1" height="285px"/>

<img src="http://www.cyclewack.com/thumbnail.php?pic=uplimg/img_A_101670_41204587b0db7ed427ebe0e5654c6c78.jpg&w=500&sq=Y&b=Y" height="340px"/><img src="http://3.bp.blogspot.com/-iXqTjWlYbDY/T6_fa073rII/AAAAAAAAJg4/_6eo9sX7jCE/s640/Picture+17.png" height="340px"/><img src="http://t0.gstatic.com/images?q=tbn:ANd9GcQzBZK5GVxjHihK_mV2kj2ko_jOzyTru 8HfYFFyIJGUuWMVdclyzw&t=1" height="340px"/>

<img src="http://www.tz350.net/images/750/tz750b_frame_restoration1.jpg" height="340px"/><img src="http://raresportbikesforsale.com/wp-content/uploads/2011/01/tz-tank-frame.jpg" height="340px"/><img src="http://raresportbikesforsale.com/wp-content/uploads/2011/01/tz-frame-outside.jpg" height="340px"/><img src="http://2.bp.blogspot.com/-XwklxkAk3FQ/T6_fefJEOfI/AAAAAAAAJhA/uJh89_78DEg/s1600/Picture+18.png" height="340px"/>

[Frits Overmars]

Does anyone remember if these "other files" were ever downloded and where I can find them?I never uploaded them because I forgot how to. Uploading the Aprilia files already was a hell of a job. One cannot normally upload ZIP-files here; Mental Trousers worked out a way for me to do it anyway, but it took a fair bit of trial and error and the method that finally worked was so roundabout that I don't remember how it went. Yes, I know about MegaUpload and similar sites, but I have my reasons not to use them.

[TZ350]

I never uploaded them because I forgot how to. Uploading the Aprilia files already was a hell of a job.

Thanks Frits, the Aprilia files are much appreciated, may be the other files someday when its easier to upload zip files.


Yes, I know about MegaUpload and similar sites, but I have my reasons not to use them.

273381

http://www.3news.co.nz/VIDEO-What-really-happened-in-the-Dotcom-raid/tabid/817/articleID/264651/Default.aspx

I don't think MegaUpload is operating now that our Police raided Kims mansion north of Auckland. The raid was a bit heavy handed, I guess our Government wanted to impress the Movie Mogiels in HollyWood with how tough we can be.

273382

The MegaUpLoad team, Kim DotCom is on the right

<iframe src="http://www.youtube.com/embed/8CvRSZxqk_I" allowfullscreen="" frameborder="0" height="315" width="560"></iframe>

Now we have a politician that forgot Kim gave him 50K towards his election campaign and a Prime Minister who has had to apologise for illegal surveillance on a New Zealand resident and Govt security organisations that have excedded their brief.

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So far Kim has come off looking dignified, and NZ looks to be blessed with strong politicaly independent Judges while the Police and Politicians are looking pretty incompetent, its been Real Keystone Cops Stuff.......

This story wont be going away anytime soon.

[Yow Ling]

Thanks Frits, the Aprilia files are much appreciated, may be the other files someday when its easier to upload zip files.



273381

http://www.3news.co.nz/VIDEO-What-really-happened-in-the-Dotcom-raid/tabid/817/articleID/264651/Default.aspx

I don't think MegaUpload is operating now that our Police raided Kims mansion. The raid was a bit heavy handed, I guess our Government wanted to impress the Movie Mogiels with how tough we can be.

273382

Kim DotCom is on the right

273380

So far we have a politician that forgot Kim gave him 50K towards his election campaign and a Prime Minister who has had to apologise for illegal surveillance on a New Zealand resident and Govt security organisations that have exceded their brief.

This story wont be going away anytime soon.

Kim has bought a bucket and will be racing at Mt Wellington

[wobbly]

You mean Kim will be bringing a bucket of US $100 bills.

[Yow Ling]

Kim is building a new Bucket track and it will be free racing for all New Zealanders, errr maybe Im confusing it with the free broadband

[husaberg]

The interesting thing is they (The not so secret government spy agency) are not allowed to spy on KIM cause he is a NZ resident. but yet we have at least 2 (not so secret)spy bases that spy on everything and everyone.
If i say I add the phase lets make a bomb (which he has made a bomb load of money) that will get red flagged...........

Kim on a bucket would make an interesting mobile chicane..........

Back to bikes What fell off my TZ post was that at one stage i believe NZ had 9 TZ700/750 (mostly twin shocks). the first race that the big TZ won was here in NZ. Not in the USA as commonly reported. The one that Boote race was converted to single shock quite early after seeing the works bikes
Brent Jones was racing the Hawera Motorcyles TZ750 (that was originally Trevor Discombs bike) reputedly at the time the most original in the world ) as late as 1986.


OH Frits if you don't want to go to the trouble of posting the files email them to me i would be happy to do it for you................

[jasonu]

Kim has bought a bucket and will be racing at Mt Wellington

It would have to be a fairly big bucket to haul that fat slob around.

[jasonu]

The interesting thing is they (The not so secret government spy agency) are not allowed to spy on KIM cause he is a NZ resident. but yet we have at least 2 (not so secret)spy bases that spy on everything and everyone.
If i say I add the phase lets make a bomb (which he has made a bomb load of money) that will get red flagged...........

Kim on a bucket would make an interesting mobile chicane..........

Back to bikes What fell off my TZ post was that at one stage i believe NZ had 9 TZ700/750 (mostly twin shocks). the first race that the big TZ won was here in NZ. Not in the USA as commonly reported. The one that Boote race was converted to single shock quite early after seeing the works bikes
Brent Jones was racing the Hawera Motorcyles TZ750 (that was originally Trevor Discombs bike) reputedly at the time the most original in the world ) as late as 1986.


OH Frits if you don't want to go to the trouble of posting the files email them to me i would be happy to do it for you................

I remember Richard Scott raceing one at Pukekohe against the late Roger Freeth. It totally laid waste to all others on the back straight but I don't think it won. In an interview afterwards he said the bike was a 'handful'.

[dinamik2t]

OH Frits if you don't want to go to the trouble of posting the files email them to me i would be happy to do it for you................

Thank you for the goodwill Frits. Yes, that is one offer.
If you and Mental agree, perhaps there's another: pm us the method of ziploading from Mental T, we will fiddle with it and return you a precise tutorial, so that you can do it directly from your pc!

[cotswold]

It would have to be a fairly big bucket to haul that fat slob around.

He could use that big one from wellington

[husaberg]

He could use that big one from wellington

:corn:..........

I remember Richard Scott raceing one at Pukekohe against the late Roger Freeth. It totally laid waste to all others on the back straight but I don't think it won. In an interview afterwards he said the bike was a 'handful'.
Richard Scott well underrated by many. joined Honda Britten only for them to fold. Can't remember what happened with Roberts Lucky strike (did he get hurt?)
I recall reading about him bringing out a RS500 here over the Northern Hemisphere winter.
I guess at the time mid 80's that should have been a turkey shoot. Although who knows, he was going to do the street circuits as well.

[Grumph]

:corn:..........

Richard Scott well underrated by many. joined Honda Britten only for them to fold. Can't remember what happened with Roberts Lucky strike (did he get hurt?)
I recall reading about him bringing out a RS500 here over the Northern Hemisphere winter.
I guess at the time mid 80's that should have been a turkey shoot. Although who knows, he was going to do the street circuits as well.

It was a turkey shoot the first year...and street circuits too...2nd year doing only selected rounds it wasn't. Don't know why.
Maybe shortage of parts/budget....talking to Ron Grant at the time, most of his mechanics were leaving at the end of the trip. To my surprise I got offered a job....too old & fucked even then.

[jasonu]

:corn:..........


I recall reading about him bringing out a RS500 here over the Northern Hemisphere winter.
I guess at the time mid 80's that should have been a turkey shoot. Although who knows, he was going to do the street circuits as well.

I saw Richard Scott race the RS500 triple in Fanganui in the mid-late 1980's. I have some pictures of it somewhere. I know he had a bike shop in Taupo for a while too.

[TZ350]

Page 640 links list to be placed here.

I have been collecting what I can on pipes, there is more on pages 620 630 and 650.


Well its a bit of a stretch to try and be specific with so many variables involved but I will try.
What you are dealing with is a combination of static com and the dynamic com created by the efficiency of the engine spec, along with the added quirk of small bores being able to withstand more of both.
The more an engines overall spec is synergistic and SOTA then the less static com is needed nor is it in fact desirable.
So - with very average port/duct geometry, a very average pipe design, a very average ignition curve but using Avgas, then at the very least we need 15:1 full stroke com to get close to optimum, with EX durations between 196 and 202, where you need to be to make any power at all.
Avgas burns so close to 105 unleaded race gas, in power and reaction to com that its indistinguishable on a dyno, except that Avgas will always withstand more com or a lean condition better. Unleaded hates com but loves timing - as a general rule, the opposite of proper race gas or Avgas.
As Avgas is allowed, and we are discussing small bore race engines with sub optimal ports/pipes etc then I would say around 15.8 would work fine.
On pump gas, be it 91/95 or crap 98 then reduce this to 13.8 and wind in lots of static advance.
Avgas isnt created for what we are doing, but its cheap enough,available at any airport,and works real well when pushed to the edge of the tuning envelope.
The other issue is that to be effective, the squish clearance should be just above what would give zero clearance in an overev situation.
Thus any 50 or 100 cc bucket is able to run down at 0.6mm with complete safety, without running into issues of excessive squish velocity, unless you are well over 50% SAR.
But dont give me any grief when the thing melts using an 8 plug when any engine making any power at all, should have a 10 iridium as a baseline.


Sorry my mistake - I was referencing to water-cooled numbers.
For air - cooled, take one ratio less in both cases,ie 15.8 down to 14.8, again as the small bore/displacement allows alot more leeway..


Very interesting and Yes I would think it fair to measure 2-stroke CC's that way ........



It appears "compression cannot commence, before exhaust port is closed" untill you think about the role of the expansion chamber.



When you think about the plugging effect of the return pressure wave from the expansion chamber stopping fresh charge from spilling out of the cylinder as the piston starts on its way back up to close the exhaust port and maybe even stuffing some back in, in the last moments of closing.

You can see how compression of the fresh charge can happen earler than the exahust port closing point, effectivly making it a bigger engine when its "on the pipe". Some call it the supercharging effect..... whether it results in more than 100% volumetric efficency of the total swept volume I don't know, but it certainly gives more than a 100% of the swept area above the exhaust port.

There it is, the whole mistery of racing 2-strokes reveled in the last two posts, everything else is just detail, thanks Dutchee.


I posted about this a while ago.The chamber needs to be about the swept vol of the cylinder.
When its big enough, going bigger does nothing.
The connecting tube should be about 1/2 the header dia, as short as possible, with the controlling throttle plate as close to the pipe as you can get it, and as close to the flange as you can get it.
The resonant effect works up to a specific rpm, then kills power real quick, so you need an rpm "switch" to control a solenoid that quickly snaps the plate open at a set point,unlike a powervalve that can be ramped.
Many current cylinders have an ATAC volume within the casting that is opened/closed at the same time as the powervalve.
This is easy but for sure not the best setup.


The cylinders that use the powervalve action to open and close a port linking to a chamber within the casting are very limited by physical room.
We tested a couple of sizes of connecting tube and plate valve, and found that if it was smaller than 1/2 the header dia it didnt work near as well.Bigger than that and the flow disruption lost top end power.
We had a 20mm tube on a 43mm header for the 166cc cylinder size, with a 150cc chamber, and as I said this gave around 28% more power just below where the valve closed.


Two strokes like an ignition curve approximating to an inverse of the power curve.
With around 28* in the mid range, that ramps up from an easy kick starting 10* at idle to about 1500,2000 rpm.
Then as the bmep rises and the pipe gets in sync with the port we pull out timing in relation to the dynamic compression created by the wave action, to prevent detonation in the end gasses.
Most engines like around 15* of timing at peak torque, we then drop this away after peak to increase the heat released into the pipe.
We have a finite amount of heat energy to use to heat trapped combustion gas,heat the water, heat the piston/head, or release it into the pipe.
The ignition delay sets the amount dispersed into each element and how much this creates power at the crank is set by the interaction of each component part.


Apologies for not reacting a single time since 11 October. I did try to log on to this forum every day, but each time I got the message
The website cannot display the page HTTP 500. Most likely causes:
* The website is under maintenance.
* The website has a programming error.
I have had the same problem a couple of times in the past, but never as badly as these past two weeks. Any suggestions?

Now that I finally got through (heaven knows why, and heaven knows what will happen the next time I try to log on) I can give a short reaction to some (not all) of the items that went on during my unvoluntary absence.

In 1993 Itoh first rode a Honda NSR500 with water injection into the headers. No injection-water cooling (the small bottom radiator is just a part of the total cooling system as this picture will show), no double-wall constructions, no recirculation, just a simple total-loss system.
It did work to some extent; bottom power improved noticeably. The problem was that once you got the revs up and cut the water injection, the effect of the cooling water on the pipe resonance frequency did not disappear quickly enough. Mike Doohan used it once or twice but never liked it, so it was binned.
Aprilia tried such a system a couple of years before Honda did, in 1987, on Loris Reggiani's works 250 twin. It added 10 HP at 10.000 rpm and it took 0.000 seconds off the laptimes because Reggiani never ran below 11.000 rpm, so the system was scrapped, recovering weight and simplicity.

Somebody asked about the Aprilia's inlet disk diameter. From memory I would say it was 126 mm.

Optimized disk inlets do not generate pulses: you open the disk when the crankcase pressure is equal to the pressure just outside the disk. Opening it any sooner would cause a loss of mixture to the outside world; opening it any later would be a waste of time*area.
You close the disk when the inlet flow has come to a stop. At that moment the pressure at the outside face of the disk will be equal to the pressure in the crankcase, but it will be higher than the atmospheric pressure, so there will be some blow-back, but that does not come out of the crankcase (assuming your closing timing is spot-on); it is just mixture feathering back from the high-density zone outside the disk. For that matter, every conventional inlet system (disk, piston, reed) will show the same blow-back tendency. And it may not be even visible from the outside; maybe the cloud of blow-back moves just a few centimeters and never really exits the inlet tract.
By the way, closing an inlet disk too early (or revving the engine higher than the inlet system's frequency would like to) will generate serious blow-back because then the closing disk interrupts an inward-bound flow which will violently bounce off the disk.
You can observe this very nicely on a dyno: looking into the carburetter you can see the fuel spray exiting the mixing tube and curving towards the crankcase. But rev it high enough and you will see this curving change into a steep front of mixture.

PS: I am sorry to say that time does not permit me to answer private messages. I apologize, but I hope you will understand.


You are right, Husaberg. When you mentioned a small radiator, I did confuse the lower radiator with this tiny one. I cannot explain either what else it could be (I hardly expect Honda experimented with a water-cooled motor control unit) but then I can't see any sense in cooling that pipe injection water either; its container was built into the gas tank where the water will never pick up any heat.
And I know for a fact that the pipe injection system was total-loss. Honda (and Aprilia six years before them) already had a problem with the cooling effect not wearing off quickly enough once you got into the power band; the problem would have been far worse with double-walled light-alloy headers.

You can notice some blow-back at low revs + full throttle (only normal); it disappears at medium revs and comes back at high revs. So yes, this might be an indication of an early-closing disk.
You can try closing it 5° later but I would look at the inlet tract length first. If you can shorten that, you may solve the high-rev blow-back without the need for a late-closing disk. That would make setting the carburation a lot easier and it would also lower the inertia of the mixture column in the inlet tract, which in turn would make it easier to get this column up to speed; especially important when you have to use a small-bore carburetter.
O, and one more thing, TZ350. Fritz is German. I am a Dutchie and I spell my first name with an s .


I've got it, and some more papers from 'Prof Bob' as he was called in the GP-team. Robert Fleck too used a simple total-loss direct injection system.
Alas, these papers are at my home and I am not, and I won't be for some time.
Translating it back into English would mean removing the Spanish(!) voice that's talking through the original comment. I have enough Spanish, and some English as well, but this two-tongue Spanglish makes it hard to decipher. Anyway, it says there is water injected into the pipes; nothing new.
Not quite. Adjusting pipe or header lengths would require more mechanics and a large battery to drive the servo; Dutch double sidecar-world champ Egbert Streuer tried sliding end cones in his four pipes. As it turned out, over the entire GP-season there was only one corner (the hairpin at La source, Franchorcamps, Belgium) where it was a real advantage, so he dumped the whole package.

Exhaust power valves, if they're really good, shorten the exhaust timing, which costs torque because for true resonance you need an effective exhaust opening (and closing) period of 180 crank degrees.
Everyday exhaust power valves spoil the primary exhaust pulse, resulting in a weaker return pulse that won't do much harm, but not much good either.
Atac chambers lower the resonance frequency of the exhaust system, but a great deal of the return pulse energy is wasted in raising the pressure in the Atac chamber instead of the pressure in the cylinder.
The best way out of all of this would be a continuously variable transmission and I would have developed one a long time ago if only it had been allowed in GP racing...
I would appreciate that.


Bimota did that once: they built a pressurized thin-wall tubular frame with a manometer, so you could scientifically establish when the frame had developed a crack.
Added rigidity: sure. Maybe not so that you'd notice, but it certainly won't hurt. I once filled most cavities in my car with expanding building foam. It made the car feel twice as stiff!
Going electric on the movable pipes is not too bad either. I was talking about a Yam TZ500 four cylinder sidecar engine, but for a single the electricity consumption will not be all that much. Here are some pictures to wet your appetite:



"Is there still a place for them?" I should think so; look at the Aprilia RSA125. There the cover does two things: shield the pipe from a cold air stream, but more importantly, as you can tell by the shield covering only the top half of the pipe: shield the crankcase from radiated pipe heat.
How much difference? We can only guess (which I avoid as much as possible) because nobody ever took the trouble of measuring the difference on a real track (were measuring the power would not be simple anyhow). The crankcase-shielding will give more power everywhere and the pipe-heat conservation will give more overrun which is extremely import for lap times.


Page 350


"Is there still a place for them?" I should think so; look at the Aprilia RSA125. There the cover does two things: shield the pipe from a cold air stream, but more importantly, as you can tell by the shield covering only the top half of the pipe: shield the crankcase from radiated pipe heat.
How much difference? We can only guess (which I avoid as much as possible) because nobody ever took the trouble of measuring the difference on a real track (were measuring the power would not be simple anyhow). The crankcase-shielding will give more power everywhere and the pipe-heat conservation will give more overrun which is extremely import for lap times.



The exhaust open point has very little to do with creating power due to "pressure" on the piston for "longer" with lower timings.
The gas pressures soon after TDC ,that creates the real power, is up over 80 bar, the pressure at Ex open is a couple of bar at best.
Moving from 200* to say 190* creates jack shit extra exertion of pressure on the piston to create torque, that then creates HP.
But the real issue is that down at 190* duration we get a huge amount of superposition of the gas pulse exiting the exhaust, on top of the residual pressure at the port.
This adding of a new pulse on top of an existing residual pressure means the wave front running down into the header has a huge relative amplitude, and this creates a huge depression at the port around BDC.
This also means we have port/pipe resonance over a much wider range and at a much high higher level than can be achieved at 200* duration.
In a conventional design we are forced into a corner by needing to create as much BlowDown STA as we can, and raising the timing is the only available route.
This pushes us away from the ideal port/pipe interaction timings, but is a compromise we are forced to accept to create the + 200psi bmep's needed, to be competitive.
Just another small detail that many overlook, or are unaware of.


Neels van NieKerk auther of EngMod2T

As far as squish is concerned whether it helps or not depends on the residual turbulence at the time of combustion. As for squish quenching the flame at the edge of the squish band to stop detonation is not looking very likely. http://home.earthlink.net/~scloughn/id21.html

250292 Tail pipe entry geometry http://www.google.co.nz/#sclient=psy-ab&hl=en&source=hp&q=engmod2t+simulation&pbx=1&oq=engmod2t+simulation&aq=f&aqi=&aql=&gs_sm=e&gs_upl=12692l12692l0l14059l1l1l0l0l0l0l290l290l2-1l1l0&bav=on.2,or.r_gc.r_pw.,cf.osb&fp=7b5dd5d7c296b0b3&biw=1024&bih=574

250284 (2004) EngMod2T manual :- http://www.rddreams.com/neels/engmod2t.pdf

This manual is a bit dated but worth a look, hopefully someone can find a more recent version for us to look at.

Obtaining the EngMod2T suite of programs
The software price is $400.00. To purchase it email Neels van Niekerk at
vannik@mweb.co.za with a request. The software will then be emailed to you after which you
install it on your PC. The pre and post processors together with all the help files should then
work. EngMod2T requires a licence file to run. A one month evaluation license can be
provided. If after reading the help files you should decide to purchase the software contact
Neels van Niekerk to obtain banking details. Once proof of payment has been received the
licence file will be sent to you. The licence is for one computer only.


You have to stay within certain length percentage limits for all elements of the exhaust system; you cannot make one part a lot longer or shorter in relation to the others without losing power somewhere.
It is best to concentrate on getting all dimensions correct for maximum power. In the high gears you don't ride low revs and in the low gears you'll have enough low-down power left to pull a wheelie or spin out the rear wheel (I'm not talking about buckets though, so you might want to reconsider your case).
If you have a decent setup for angle*areas, pipe, carburation and ignition, the necessary overrev potential will come naturally; no need to sacrifice maximum power in order to make it rev a little higher.


The wide septums between the transfer ducts is there for two reasons.
One it reduces the duct entry area, and thus the ratio between the port and entry areas.
This drops the volume of the duct.A smaller volume sitting at the port has less inertia that the pressure ratio across the port has to accelerate into the cylinder.
Also consider that if you calculate the delivery ratio at full power and compare this to the cylinder swept volume of the cylinder, the air/fuel mixture sitting in the ducts
is more than enough to fill the cylinder - the is very little "flow" from the case, around the duct and into the cylinder in reality.

Secondly, the front and rear wall radial angles of the ducts are maintained all the way from the port, out to the duct entry.
As in 4T ports, trying to "bend" flow in two dimensions concurrently,lowers the bulk flow rate considerably.
Thus the ducts taper all the way from entry to exit, but only change direction in the one plane, around the short turn to give the correct axial entry angle.
The old bullshit you see of sharp divider edges is just that.
Only supersonic aircraft have sharp leading edges on the wings,and we certainly arent dealing with supersonic flow in transfer ducting.
Any flow loss due to the corners on the flat topped septums is way offset by the better directional control and reduced volume of the duct acting to fill the cylinder quicker.


It matters, Pete, as a lot of Italian kart engine manufacturers and tuners will reluctantly confirm. They all copied the Aprilia cylinder and while they were at it, they could not resist correcting the 'errors' that Jan Thiel had left behind. And then they were surprised when the engine made less power instead of more .
It's not that simple to improve the best two-stroke cylinder in history .


The outer transfer duct radius is utterly unimportant; there the charge has no option but to go where the duct wall leads it. But the inner duct radius is very important: it should be as large as possible to avoid flow detachment. If you manage to keep the flow clinging to the inner surface (the Coanda effect), there will be less pressure-absorbing turbulence, so the flow will meet less resistance, transport more mass and deliver it where you want it to go.
The golden rule of flow: look for sharp inner edges and remove them. It always works.

The radii at the bottom bore edges, as visible in the picture above, yielded 1 HP; that's about 2% of the total power. The egdes where the transfer port windows cut the bore, should not be radiused; you do not want to promote inflow of waste gas into the transfer ducts. Here only the top and bottom edges should be chamfered lightly to make life easier for the piston ring.
There should be no widening just before the port exit; the duct cross-section area should gradually move from entry area to exit area. And with the inner curvature of the duct fixed, this more or less lays down the shape of the outer curvature.

Assuming that the flow in a duct will accelerate faster as a result of narrowing that duct is an ineradicable misconception. If it were true, it would mean that a duct narrowing to zero would yield an infinite flow velocity......
Flow velocity depends on the pressure difference between entry and exit of a duct, and in the case of an engine, where the flow constantly accelerates and decelerates, it also depends on the column length of the mass in the duct. It does not depend on the column's cross-area; twice the area would mean twice the mass per mm column length, but it also means that the cross-area exposed to the pressure difference is twice as big.
A smaller cross-area can have the effect that because of the reduced mass flow the pressure in the crankcase does not fall as quickly, which in turn may lead to a longer-lasting acceleration of the flow and thus a slightly higher top speed. But it will also mean less mass transport during the transfer phase.

The duct entry area of the Aprilia cylinder's B-ports is slightly smaller than their port exit area. This stems from the old obligation to develop cylinders that had to fit the existing crankcases of the Aprilia RSW engine, of which there are hundreds around. the RSA engine did not have this limitation, but simply enlarging the B-duct entries disturbed the scavenging, so the ducts were left as they were (and remember: while the B-ports' exit areas are only open part of the time, the entry areas are open all the time).
The transfer timing is 130° for the A-ports (they are really close to the auxiliary exhaust ports) and 132° for the B-ports and the C-port.

[TZ350]

Someone asked what I used connecting my laptop to the Ignitec.

273441

I use Windows XP, this USB to Serial converter and the driver that came with it and a proper Serial RS 232 cable, not a 9 pin extension cable and most importantly a 5K resistor plug cap, a resistor plug would be good to but I have not tried that yet.

Most of my computer freezing problems went away when I used the cable adapter and completely vanished when I fitted a 5K plug cap.

[speedpro]

I recall piling into the sweeper at Baypark on my GSX1100. Had the left pipe dragging hard in an effort to stay in front of a bike I could hear behind me. More or less got to the back straight and if I recall correctly Discombe shot past like I'd had some sort of mechanical failure. It was a long time ago but it still sticks in my mind.

[Rick 52]

Crank shaft balance factor ...I have a TF125 that I picked up in a RG50 frame some years ago and it's been a great little engine with very little vibration, the engine is now ready for a little work and a TS gear box so while the cases were open team ESE and myself were keen to measure the crank balance factor as people have said TF engines vibrate a lot and crack pistons and my bike has not cracked a piston in the time I have raced it.
Teezee helped me understand what we were doing with the balance factor and measured up the new gearbox that will fit in with out any work ..the ideal crank balance factor for my bike is..49%.of the portion of the "Reciprocating Mass" that is balanced by the "Counter Balance" portion of the crankshaft because that is what it worked out to be and it looks standard apart from the holes in the crank being filled with resin ..now to get it back together before he weekend ..

[Grumph]

Crank shaft balance factor ...I have a TF125 that I picked up in a RG50 frame some years ago and it's been a great little engine with very little vibration, the engine is now ready for a little work and a TS gear box so while the cases were open team ESE and myself were keen to measure the crank balance factor as people have said TF engines vibrate a lot and crack pistons and my bike has not cracked a piston in the time I have raced it.
Teezee helped me understand what we were doing with the balance factor and measured up the new gearbox that will fit in with out any work ..the ideal crank balance factor for my bike is..49%.of the portion of the "Reciprocating Mass" that is balanced by the "Counter Balance" portion of the crankshaft because that is what it worked out to be and it looks standard apart from the holes in the crank being filled with resin ..now to get it back together before he weekend ..

There is no "ideal" balance factor for a single....yours happens to work acceptably in that frame.
If they have a rep for vibration in the std frame, 49% as the std balance factor explains some of that.....

[wobbly]

WinDoze 7 works fine with a good quality serial adapter as long as you install the adapter driver as well as the newer downloadable driver from Ignitech.
All modern bikes and cars have resistor caps, and its getting difficult now to buy a non resistor plug.
The combination of resistor plug and cap form a low pass filter in concert with the capacitance of the plug lead, killing RF that usb is very sensitive to.
A USB optical isolator does help as well, but in the main, keeping the coil drive wire away from trigger and TPS inputs will solve crashing issues.
The newer program does have some issue with not doing a full reprogram when running on the dyno - and doing multiple changes, but simply switching the ecu on/off quickly resets it,and it then works fine.
I have used top quality spiral wound plug wire and ditched the resistor caps, for a very high power spark setup, and this worked equally well.
The rare earth fine wire iridium/platinum electrode and ground strap plugs are so good now that NGK should offer a trade in discount so all you tight arses finally get rid of all the
B10EGV and N82G plugs that have been lying in the toolbox for 25 years - as you SHOULD be using the resistor type..

[TZ350]

...the ideal crank balance factor for my bike is..49%...


There is no "ideal" balance factor for a single....yours happens to work acceptably in that frame...

True ... and its why Rick said "ideal crank balance factor for my bike". We have always said there is no universal ideal, only what works best in your circumstances, there may be some general factor that gets you into the ballpark but the ideal or best for a particular setup is found by trial and error.

[twotempi]

True ...The rare earth fine wire iridium/platinum electrode and ground strap plugs are so good now that NGK should offer a trade in discount so all you tight arses finally get rid of all the
B10EGV and N82G plugs that have been lying in the toolbox for 25 years.r.

:clap::clap::clap: What do you mean !! Paid good money for all the plugs rattling around in the bottom of the toolbox

But I am not tight as someone one I know who bead-blasts all his EGV plugs at the beginning of the season so he has a fresh lot for that season.

Has done it for years with no apparent problems. Racing on a pension means you have to use what you own !!

Maybe the "old" EGV plugs were better quality !!

;);););)

[wobbly]

The new type 7376 plugs are ideal for bead blasting after every meeting.
As I insist on plug chops after every race and change the jets at least 3 times a day when doing "real "racing, reading the insulator and ground strap
is impossible if the thing is covered in oily shit from idling around - at all.

[husaberg]

The new type 7376 plugs are ideal for bead blasting after every meeting.
As I insist on plug chops after every race and change the jets at least 3 times a day when doing "real "racing, reading the insulator and ground strap
is impossible if the thing is covered in oily shit from idling around - at all.

<img src="http://www.kell-strom.com/tools/fedmogul/graphics/av475r_200.jpg" height="300px"/><img src="http://www.1stopretroshop.com/photos/n89428.jpg" height="300px"/><img src="http://www.carandclassic.co.uk/uploads/cars/any/1091744.jpg" height="300px"/>

When i was young i always felt so guilty using these (far right) but long ago nearly every country garage (Remember those) had a champion or similar one complete with tester.
After Wobs post.. maybe not so much......... i was told they damaged the insulator and rounded off the edges etc (They were filled with garnet i think),
The old man still has one, Er... i might just have to liberate it.............

[speedpro]

True ... and its why Rick said "ideal crank balance factor for my bike". We have always said there is no universal ideal, only what works best in your circumstances, there may be some general factor that gets you into the ballpark but the ideal or best for a particular setup is found by trial and error.

I rebalanced my TS engine. The differance in vibration was great enough for Pete Sales to comment when I was next visiting for more dyno tuning. My bike vibrated at higher revs so it needed a lower % balance factor. As a trial, no maths involved, I put a slug of aluminium into the larger hole in each crank web next to the big end pin. I never did check the numbers but it worked perfectly. The motor vibed a bit low down but was sweet when being raced. I really wouldn't worry about the maths. Just check where it vibrates, high or low compared to where you use it and adjust the balance factor an amount.

[richban]

I rebalanced my TS engine. The differance in vibration was great enough for Pete Sales to comment when I was next visiting for more dyno tuning. My bike vibrated at higher revs so it needed a lower % balance factor. As a trial, no maths involved, I put a slug of aluminium into the larger hole in each crank web next to the big end pin. I never did check the numbers but it worked perfectly. The motor vibed a bit low down but was sweet when being raced. I really wouldn't worry about the maths. Just check where it vibrates, high or low compared to where you use it and adjust the balance factor an amount.

So do you think its possible to get an FXR crank to work without a balance shaft?

[speedpro]

I have removed the balance shaft from my current MB engine and rebalanced the crankshaft. Maths were involved this time and they told me I had to increase the balance factor of the crank. It works fine on my MB so I would expect you could do it to your FXR.

The MB balance shaft weight assisted the crankshaft balance in line with the bore and opposed it at right anges. By removing it I reduced the amount of rotating mass trying to balance the reciprocating mass which was the right direction to go with the increased revs but it was too much of a reduction so I had to increase the % on the crank itself.

[Yow Ling]

So do you think its possible to get an FXR crank to work without a balance shaft?

Ive seen a few come out , then the bikes fall to bits so they go back in, except for the guys who leave the bearing in the blind hole because its too hard to get out, they usually need new crankcases, crank and gearbox after 10 minutes running

[twotempi]

So I take it that is a "NO" then ??

[husaberg]

So I take it that is a "NO" then ??
the idea has some merit.......for the greater good.........:laugh:

[speedpro]

MBs are the same. If you disconnect the balance shaft or take it out with no other mods they vibrate like crazy. As I pointed out, without the balance shaft the counterbalance is too light. People then put the balance shafts back in. I've rebalanced my crankshaft. It's dead easy, all I've done is drill 2 8mm holes and 2 10mm holes around the big end pin area of each crank web.

[husaberg]

MBs are the same. If you disconnect the balance shaft or take it out with no other mods they vibrate like crazy. As I pointed out, without the balance shaft the counterbalance is too light. People then put the balance shafts back in. I've rebalanced my crankshaft. It's dead easy, all I've done is drill 2 8mm holes and 2 10mm holes around the big end pin area of each crank web.

I have heard that before. Dave maybe?
My old H100, which i guess is more subtly different than most people would expect was fine without it(in a MB5 frame).
I also remember pulling apart a AC CR80 and noticing it was actually machined for a balancer shaft (i guess betraying it true design origins)
But in my opinion the tiny possible gains are far outweighed by the negative aspects. I personally wouldn't do it again. But each his own you have 30hp and i have er..... i have a pile of bits. My theory is even with design margin the crankcase are designed to have them and i guess are pared down a it accordingly material wise.
But shove a CR500 in an alloy frame then after a 30 minute ride. A balance shaft or a more suitable balance factor would be a welcome addition. They are much more acceptable in the steel frame. As suitable Balance factors are off course effected by both frame material, design and engine inclination as well.
Of course some people's engine vibration problems relate more to the engine mounts sloppiness and untrue crankshafts as well.........

[SS90]

When Honda added balance shafts to Rs125's, the differenece was phenominal, I was always of the opinion from then that the advantages from having one, far outweight any disadvantage.
The early stuff was terrible for cracking chambers and rooting stators (although the flywheels where quite heavy)

As always, I feel a new set of tyres and correctly set up bike will be a far greater advantage than faffing about trying to get it close to correct after removing a balance shaft in the forlorn hope of less weight/ minute gain in power.

Russel Bleach always used to (helpfully) lecture me about "tuning to a standstill", as always, he was right.

[Grumph]

I've only ever found one motor that gained from balance shaft removal - the big kawasaki four ZX/ZZR family - and that was only because the shaft spent a lot of it's time under the oil level. Churning losses were significant.

Unless you have a really good handle on balance theory and practise, leave it in.

[Henk]

I took one out, rode it for a day then put it back in, didn't seem to make any difference powerwise but man it shook.

[wobbly]

As always its a combination of factors that makes any modification worthwhile or not.
The old RS125 was based on a MX case, and when used in the roadrace frame the balance factor was wrong for the rpm it was expected to pull - but that was because it used the original MX crank.
The stators were a shit design and doomed to fail even if it didnt vibrate, and the pipe had a slip joint at the end of the header, another shit design doomed to fail.
But in a kart, the old MX based engine was as smooth as any, and with expoxyed or better later model stators, and a pipe with a proper header design they were able to be tuned harder than the new engine.
Especially if you fitted a new solenoid PJ carb and Ignitech to drive it.

The newer RS125 was specifically designed for the roadracer, and had a very laydown cylinder layout.
But for people to believe that removing the balance shaft would be a performance enhancement,due to reducing the rotating inertia, are sorely mistaken.
The small inner rotor flywheel, doesnt have sufficient inertia, and if you remove the balance shaft, and or remove the rotor to convert to total loss, the engine simply will not rev, using a stock crank.
Its been proven hundreds of times, and Honda and VHM offer high inertia cranks specifically for use without a rotor.
ie remove the shaft,then you have to add weight back into the crank to get it balanced - so the point was????
Rebalancing the crank to reduce the vibes in the power range used, all but adds as much inertia back into the system as was there before, and except for reducing some balance shaft support bearing drag , removing the
shaft really is of no advantage.
But a balance shaft in a small single simply isnt needed anyway if the crank is correctly balanced for the chassis its used in.
Plenty of single MX and kart motors are perfectly fine without any balance shaft.
Big clunkers throw alot of big amplitude vibes around, and as everyone knows a CR500 would be wonderful if it had one.

[richban]

I took one out, rode it for a day then put it back in, didn't seem to make any difference powerwise but man it shook.

Best one I saw was a guy who just removed the balance drive gear but left the shaft in. The front wheel nearly left the ground when he gave it a rev. Is that even possible. Well thats what he told me anyway. crazy vibration.

[Henk]

I'd have thought that the saft without the gear would just swing gently as it pleased and occasionaly bang into the crank as it was spining, scary thought.

[richban]

I'd have thought that the saft without the gear would just swing gently as it pleased and occasionaly bang into the crank as it was spining, scary thought.

After just splitting my engine I think it would miss the crank. But my balance shaft is a little smaller than normal.

[F5 Dave]

A commuter bike is of course set up for doing 8000rpm max so all bets are off when raced. They will spin another 4000 & not have to cope with learner riders in slow traffic.

I took the balancer shaft off my MB50s back in the day because everyone was doing it. My H100 came without one as PO had the bearing fail & took it out to fix it. The MB in RS chassis I never put it in, partially to see how it went & on new cases I used the area for the Case reed. None of them have vibrated much at all & I hate vibey bikes. - Like really hate them.

I've been a bit lucky I guess (also paid attn to using anti vibe mounts) but the latest MB crank I have followed Mikes lead with some drilled holes. Seems to vibrate a bit more down low. Can't complain up top.

I've had mate who had done the cut the rotor off the side of RS125 crank, but of course not bought a HI crank, so it is interesting to read Wobs explanation & shows the folly of following the trends without understanding the full story. A little knowledge, as they say.

[husaberg]

<img src="http://static.flickr.com/112/278962558_a481aa48ff.jpg" width="1140px"/>
http://4.bp.blogspot.com/_UazjlEXFTmo/TFH9yX0LwpI/AAAAAAAAAGs/_T5-gBydRSI/s1600/hrc.jpg



Yeah it was a single crank four rather that a twin contra-rotating crank. So as result of the layout the engine was obviously wider but........
The weight was also further forward. less weight shorter and less losses....
Doohan reckoned the heavy balance shaft inherited from the initial big bang motor helped the handling...... makes sense. contra-rotating.
Ever noticed most bigger cc'd engined bikes seem harder to turn as a general rule even in the same frame those flywheels are effective gyros.....

Successful design it guess is about achieving the best possible compromise...........bucket loads of cash does of course, not hurt either

Not sure why then they make the twin crank 250 though.........................

i guess its the early 70 degree nsr250 (the real one not the roadie) can anyone confirm.......



http://1.bp.blogspot.com/_UazjlEXFTmo/TFH17U9cTKI/AAAAAAAAAGk/qEaVt3h2hKs/s1600/engine2.jpg

[TZ350]

273522

Fitted an air box and lost 2.5 horsepower so I had to try and get the motor working properly with my carb cover come spilled fuel catch tank thing again.

273523

The quick change air jets worked a treat.

Torque curve runs for 5k, 8 to 13, and at 13 its starts to detonate, I guess because of insufficient blow down STA at those rpm.

273521

In the end I managed several good runs @ 30hp, I hope I can do that again in a back to back test with Riches bike tomorrow night.

[ief]

Came across the smartcarb and understood Wob tested them, are they all that is claimed or just a good carb and, if any, what's the secret?

[richban]

273522

In the end I managed several good runs @ 30hp, I hope I can do that again in a back to back test with Riches bike tomorrow night.

Yes will be interesting for sure. I am picking my bike will be about 25 on your dyno. I am hoping we can get the ignitech plugged in to give it its best chance of maybe a little more. See you later today.

[wobbly]

The SmartCarb is a development of Edmonsons Lectron with a couple of important twists.
The venturi is sort of egg shaped,smaller radius at the bottom, to increase air velocity at low openings.
They have developed the flat sided needle concept further to give even better atomisation of the fuel mist that was one of the Lectrons main features.
But the real trick as far as I am concerned is the Aux Venturi that is in the top of the bellmouth.
This connects to the top of the fuel bowl, and the differing air pressure created by the engines actual flow characteristics, and the ambient pressure, vary the fuel curve dynamically.
Thus it is almost a situation of one needle fits all, but just as importantly the effect of altitude pressure on jetting is eliminated.
The first set, that I have here, was used on a 500cc 2T Banshee Quad, that was easily the fastest up Pikes last year.
And a 450 single 4T Quad won its class as well with a lap record.
When jetted correctly at sea level, the tuning doesn't change when rising the 4000 ft up the hill.
One excellent factor is that it has no idle jet circuit, in front of the slide, and thus it can be run very downdraft, creating dead straight inlets in front of the reeds on alot of engines.
I am involved in the development, and will eventually, I hope, get the import rights,but the first small 28mm production units are almost finished now,and I will be fitting one to a 50cc Bucket
to do the testing here.
The company got alot of Federal money to develop the carbs as another by product of the atomisation is an amazing increase in fuel economy - and a big reduction in emissions.
To the point that regulations are being put in place to ensure all small engines in things like generators will be required by CARB to have them fitted.

[F5 Dave]

I've been following the progress on the GasGas site & would love to chuck on on my 300 for a play, but would have to wait for the cash situation to become a bit better (& the cast versions that will be a reasonable price). Love to chuck on on the 50 to see if I could get a less picky overrev. Again even less likely to happen. My 496 being essentially the same engine what is regularly raced up Pikes would seem a candidate.

I need a sponsor. The current one is a deadbeat & should have studied Sales & embezzlement to fund me in the way I'd like to become accustomed.

[ief]

Cheers Wob.

[chrisc]

Yes will be interesting for sure. I am picking my bike will be about 25 on your dyno. I am hoping we can get the ignitech plugged in to give it its best chance of maybe a little more. See you later today.

Post the results! I'm interested/wish I was there to watch

[TZ350]

273554

A couple of trailor loads of bikes turned up at work last night, they were from Palmerston North and Wellington.

Richban, Crazyman, Bert, Regan, Dave G, Kieren all FXR150's except for Burts TZR100 in a Crazyman frame.

Stra8 Jacket and Koba will also be there.


273557

After running up my bike

273553

Rich got his new FXR/MC21 out for a run on the dyno in a true back to back test with the Beast.

<iframe src="http://www.youtube.com/embed/q9pbD4TX27A" allowfullscreen="" frameborder="0" height="315" width="420"></iframe>

273556

TeeZee Red line and Rich's FXR Blue line.

As Rich suspected the DynoDynamicks dyno in Wellington gives a reading that flatters their Harley riding clients but the Wellington and Team ESE Dyno Jets read much the same and give comparable results.

273555

It does look like my earlier setup which Avalon prefers (blue line) would be more suited to the tight Mt Wellington track.

Half way down page 500 Bucket posted links to all the relevant details about the engine.

[kel]

273556

TeeZee Red line and Rich's FXR Blue line.

As Rich suspected the DynoDynamicks dyno in Wellington gives a reading that flatters their Harley riding clients but the Wellington and Team ESE Dyno Jets read much the same.



No surprises there. Takes me back to a quote from earlier in the year
"I pulled a horsepower mugging on Rick in that last race. The beast was embarrassingly fast, clearly quicker up the straight than anything else on the track"
And I failed to win on it :facepalm:

[wax]

Anyone possibly help. I have built my new race engine. It will idle just fine but it will not rev. as soon as I get above 7-8000 rpm it splutters and just pums black goo out the exhaust. I have had a look at the timing and it running 15 down low then it goes to 30 till about 9 and drops back to 15 from 10 onwards. Even with no load on it should still rev cleanly past these points.
Im desperate and very stressed as I have a race in the next few weeks
I have tried 2 different carbs on it with no change

[jasonu]

Anyone possibly help. I have built my new race engine. It will idle just fine but it will not rev. as soon as I get above 7-8000 rpm it splutters and just pums black goo out the exhaust. I have had a look at the timing and it running 15 down low then it goes to 30 till about 9 and drops back to 15 from 10 onwards. Even with no load on it should still rev cleanly past these points.
Im desperate and very stressed as I have a race in the next few weeks
I have tried 2 different carbs on it with no change

New or different heat range spark plug maybe. I like to try the easy and cheap fixes first...

[husaberg]

New or different heat range spark plug maybe. I like to try the easy and cheap fixes first...

Sounds like it is way rich up top to me but esp hard to diagnose engines in different counties over the internet.
have you tried diferent jetting rather than carbs?(this is not meant to sound condescending btw):yes:

But pull off the plug cap as well and check the inside of the boot for any black residue is it seating on the plug properly.
some more info would be helpful.............
I once chased my tail with something similar it was...... er the mainjet had fallen out:Oops:

[cotswold]

The beast ran all day today, not at Kels pace but at my more sedate pace. It lived up to it's reputation and high sided me over the top on the first lap of the first race, a little moisture and too much clutch and throttle plus a tap from behind.
I admit I was a little apprehensive for the next race and rode like my nanny, the 3rd race I felt a lot better and was having fun chasing the lads in front but a detto type noise made me pull out, as it turned out needlessly as it was the frame breaking and knocking together causing the noise not the engine.

[Rick 52]

Team ESE , thanks for the ride on the spare bike today after my bike did a head gasket, the bike went great and even better after a little carb change to help my riding style, after explaining what i needed Teezee made the changes that made the different, what a magic little engine ! Cheers guys.

[TZ350]

273577

Round one of the North Island series, an awesome day.

Mostly FXR150's but there were quite a few interesting specials, unfortunately I didn't manage to get pictures of them all.

[TerraRoot]

sweet bikes :cool:

[TZ350]

273587

Moto Cross has the flying "W"

273586

And at Mt Welly Cotswold invented the flying Angle when the Beast High sided him.

In the first race there was a light shower of rain as the grid was forming up. Then the green flag and as the pack exited the infield onto the short back straight Cots gassed the Beast up and got it well and truly sideways. He cought it and was looking good bringing it back into line when he got a tap from behind and the Beast took its chance to spit him off, fortunatly without any real injury.

In the last race Cotswold sensibly pulled out early as he heard the engine note change and go into what sounded like detonation. A quick inspection in the pits and it looks like the front down tube has broken and that the ends clattering together was what he heard (hopefully). We will know for sure, when the engine gets pulled down in preperation for Hampton.

So ... one finish and two DNF's for the day, but great fun, and the other high lights were hanging out with the riders in our pit area and catching up with Steve and Ellen, the people from Wellington and Palmerston North and talking with the guy from Whakatane about his RG150 conversion and working with Rick trying to get something going so he could stay in the hunt for the series.

[TZ350]

Carburation.

One of the big things for me recently has been trying to get my head around the main air compensation jet and figuring out a way to find the right one.

Like everything, its simple when you know how, or at least think you do.

273619

The Red line represents a main jet (135) that is correct at peak power but is too lean at 8.5k rpm.

The Blue line represents a main jet (155) that gives good initial drive at 8.5k but becomes to rich at peak power rpm.

The trick is to use the air correction jet to join up the two lines.

I guess the way to find the correct main/air correction jet combo is to do full throttle runs and lean the main out until I have found the best shape I can in the 11 to 13.5k peak power area of the graph. Then keep richening the main up until I have optimised the 7.5 to 9.5k initial drive area of the graph.

Then having found what the best at both ends looks like, I can progressively increase the size of the air correction jet until the rich, good at 7-9.5k main also works well at 11-13.5k.

On the dyno or track I had always looked for the main that gave maximum power, I now think that approach is limited.

So the next time I am on the dyno I will be looking for a main that gives its best at the beginning of the torque curve instead of maximum power and look for the air correction jet that maximises the rest of the power curve.

[wax]

I know this is for buckets. Over here in australia we also race scooters. This is my one with the 50cc engine at the moment. I also have an 86cc engine for it. The 86cc ones will go close to 30hp
http://i215.photobucket.com/albums/cc79/waxracing/24hraerox.jpg

[TZ350]

It looks great and I would be very interested in knowing more about the CVT transmission and where I could get a good one and tune up transmission bits from.

[wax]

Are you wanting to adapt on to a bucket. They would outlaw it really fast I would think. It will kill everything on the track

[husaberg]

It looks great and I would be very interested in knowing more about the CVT transmission and where I could get a good one and tune up transmission bits from.


Engines must be derived from non-competition motorcycles.
Motocross, Road Racing, Enduro and Go Kart motors and transmission parts are not permitted.

Seems legit to me.
I mentioned the Rokon earlier it appeared to have a Sachs engine and transmission direct out of a Snowmobile.
i will post it below but you may need a alternate method of starting the beast though TZ.

My initial thoughts were to use a CVT as well semi overdrive to overlap the gears.
it would of course have two problems it would have to be modded to only offer about a .75:1 reduction (not that hard limit the travel)and it would be near impossible to fit it on the primary drive with a conventional clutch set up still in place.
Whereas on the secondary drive it would spin about 1/3-1/6 engine speed (depending on what gear it was in)which may not be a bad thing.
Possible problems with the overlaping gear ratios principal would be you would know when to change as when the cvt od kicked in the rev counter would remain stationary........it also goes against the KISS principal
As a standalone unit the Salisbury unit on the Rokon offers a overall spread of ratios between 3.76 and .087:1.
<img src="http://www.motorspecial.it/sezioni/angolo_delle_curiosit%E0/moto_rokon_cross_automatic/rokon_01.jpg" width="340px"/><img src="http://www.motorspecial.it/sezioni/angolo_delle_curiosit%E0/loghi/logo_moto_rokon_cross_automatic_00.jpg" width="440px"/><img src="http://www.ridermagazine.com/wp-content/uploads/2011/10/Rokon-RT340-Automatic1-298x192.jpg" width="340px"/>

<img src="http://books.google.co.nz/books?id=lpiMSzja6W4C&pg=PA14&lpg=PA14&dq=rokon+340+automatic&source=bl&ots=zwQxMGFbaG&sig=oBz6pM48MhjGSmUdh-Ih3NUB0Lk&hl=en&sa=X&ei=SnixULarC_CQiQe0pIDIAw&ved=0CGYQ6AEwCw#v=onepage&q=rokon%20340%20automatic&f=false" width="340px"/><img src="http://4.bp.blogspot.com/-xs5O9iyoedQ/UICUnnASH_I/AAAAAAAAD0k/P8DhOfOUIcA/s1600/114a.jpg" width="390px"/><img src="http://1.bp.blogspot.com/-TYNk_Lt_66E/UICUlpl8z1I/AAAAAAAAD0c/-Bn4TxRRAG0/s640/112a.jpg" width="380px"/>

RT340 TCR Automatic/CVT In 1974, Rokon produced the RT340 TCR Automatic, using a snowmobile-type Salsbury CVT, rear wheel drive only, and dual disc brakes. Another unusual feature was a pull cord to start the engine. The transmission freewheels with the engine at idle; starts to engage about 2800 RPM; and is tuned so the engine always runs near peak power, at 6,000 to 6,700 RPM. The lowest gear ratio is 3.76:1 and highest 0.87:1. Using a CVT allows a use of a 2-stroke cycle motor with higher power but narrow power band. The engine sound is unusual as the engine stays at a nearly fixed speed and the transmission ratio changes according to speed. The transmission freewheels when not driving forward, so there is no engine braking. The transmission is vented to the outside for cooling, and so is contaminated by stream crossings and other environmental exposure. Water causes slipping but quickly goes away; however grit can cause transmission sticking. Riding on loose surfaces is sometimes complicated, as rear wheel breakaway does not cause telltale changes in the engine sound. However, most other riding is intuitive and sometimes much more convenient as the automatic avoids engine stalls and other problems with gear selection. Operation is loud (90.3 dB(A)) as the engine is always running fast except at idle. Despite low front wheel weight, about 43%, it had trouble pulling wheelies, a problem for the targeted Enduro riding. Prototypes were raced by factory riders from 1971 to 1973 under Tom Clark; "TCR" stands for "Tom Clark Replica". In the 48th annual six-days trial, all four riders earned bronze medals for finishing. "Cycle Guide" test riders reported it superior for hill climbing and fast on hard surfaces, but poor on loose surfaces and going down hills.[1]http://en.wikipedia.org/wiki/Rokon_motorcycle
If you read the article it says acceleration was not a issue......... cornering on the tarmac might........

[wax]

water cooled is only allowed 100cc right ?? does it have to use the original cylinder.

[bucketracer]

water cooled is only allowed 100cc right ?? does it have to use the original cylinder.

Yes 100cc water cooled, 125cc air cooled.

A Bucket motor does not have to stick with the original cylinder you can fit something else if you want to.

The original scooter transmission is obviously non competition, but the after market parts are a little grey but probably legal as they are made for tuning up a road unit.

[wax]

OK there is a thing called the gp1 derbi it has a 50cc midmounted engine. this has the cvt as well as a chain drive. This uses the same cases as the 125cc aircooled piaggo engine so you can turn the 50 into a 180 if you so desire. Of course your limited to 125 and there is alot of cylidners for this engine.
http://www.stuntbase.com/slikice/derbi_project/3.jpg

http://www.sip-scootershop.com/en/products/cylinder+kit+rms+125cc+for_r10008006
http://www.bgm-tuning.com/scootermatic/piaggio-2-stroke-125-180cc-scootermatic/cylinder-heads/bgm-original-cylinder-kit-125cc-ac/
http://www.sip-scootershop.com/en/products/cylinder+kit+rms+125cc+for_r10008006

This is just a quick look around but there is alot better cylinders out there. most of them want to go 180cc but some dont. You will not be popular if you do this as it will set the bucket racing guys on fire

pm me for more information if you like

[wax]

you could use the water cooled cylinder and run an electric pump and do this.
http://www.youtube.com/watch?v=GDTXZAHGFJI
http://www.youtube.com/watch?v=p1Rp_IGqGfM
http://www.youtube.com/watch?v=Tf_ix5xMmI0

Like I said you will not be popular. I know its only 27 hp but its all the time. The motor will stay on the same rpm the whole time. max hp so no slipping clutches off the line just crank it on and you have 27hp from a stand still to the top speed. It also comes on so smoothly that you will be on the gas before any gearbox bike

[SS90]

you could use the water cooled cylinder and run an electric pump and do this.
http://www.youtube.com/watch?v=GDTXZAHGFJI
http://www.youtube.com/watch?v=p1Rp_IGqGfM
http://www.youtube.com/watch?v=Tf_ix5xMmI0

Like I said you will not be popular. I know its only 27 hp but its all the time. The motor will stay on the same rpm the whole time. max hp so no slipping clutches off the line just crank it on and you have 27hp from a stand still to the top speed. It also comes on so smoothly that you will be on the gas before any gearbox bike

I'm unsure if you have ridden a well sorted bucket, but you would find that a mid 20hp nice chassis (like an Rs125, or one if these Crazyman frames) would piss all over all but the most experienced scootermatic rider.

When raced "like for like" scootermatics are awesome to watch and compete it, and often close racing, however, (like all scooters), they oversteer chronically, due in part to their tiny wheels ( 10,12, or 13 inch for most autos), short wheels base and weight distribution.

Yes, acceleration is blistering, but it's not only about that.

CVT are great in standard form, for a host of reasons, but as soon as you want to optimise them for competition, a host of compromises must be made, not the least of all mid corner drive.

You can adapt your riding style of course, but it's one of a host of problems that make racing a standard CVT autoscooter against a modern competition bike unnappealing.

A really tight Kart track would prove a different story ( by virtue of holding everyone up mid corner, but out driving everywhere else, so much so that a scootermatic would be a weapon. But, only in this scenario, and winning this way is hardly Cricket.

Add to this that EVERY SINGLE tune up part, (with the exception of different weight rollers) come with the packaging "COMPETITION USE ONLY", yes, many people fit them on the road, however, this does not make them legal.

They are in no way eligible for buckets, I see no ambiguity in the rules that would allow this.

Now, if someone went to the effort of manufacturing different variator pullies, clutch weights, and so on, that's fine, but taking a 100 kitted cylinder (illegal), a Mallossi transmission kit (illegal) and fitting it all to set of (legal)Piaggio cases, will not all of a sudden make it legal.

I am of the opinion also that adapting (somehow) a CVT transmission to a standard bike would be more headache than it is worth, but would be happy for someone to prove me wrong.

[wax]

I have raced against something like that. they have cr85 engines in rs125 frames
http://i215.photobucket.com/albums/cc79/waxracing/wax-racing.jpg

Im not trying to get into a war whats better I never said a scooter was better or worse I was just answering a question that was asked of me, I dont know your rules which is why I was asking questions if you read just above
however i was suspecting this would be fitted into a bucket frame this get rid of the proplem of the high unsprung weight and short frame. If you look at the gp1 engine i was talking about you would see it was chain drive. I find when we race the bikes as in the picture you can eat them mid corner and while the cvt is a whole different scenario to ride diving up the inside and block passing is defiantly cricket in my mind.

[TerraRoot]

you have a great idea there wax, ss90 shot his mouth before seeing what the gp1 was.
i like the idea of a fast 125ac with 12" slicks, the 180 has such tiny squashed transfer ports.
i gotta say i don't like a CVT for corners in real life but on the track it could be great.

often though of shoving my 180 into a real frame but keeping the 13" wheels. no time.:rolleyes:

[SS90]

. If you look at the gp1 engine i was talking about you would see it was chain drive. I find when we race the bikes as in the picture you can eat them mid corner and while the cvt is a whole different scenario to ride diving up the inside and block passing is defiantly cricket in my mind.

Like under arm bowling more like :msn-wink:

In my experience, scootermatic racers against conventional geared stuff is only a novelty, as it just creates discontent from riders (like the days of F3 racing with 125GP in NZ)

Im am quite familure with the GP1, as I am sure most people are, but most of the advantages a conventional CVT scooter has (in regards to speed of turn in particularly) are negated by a convetional chassis.
I am of the opinion that putting a CVT engine into a conventional chassis would be an excersise in accomplishment only, as the reasons for desiring a CVT transmission usually come about because of too narrow power spreads, I do wonder what would be if GP bikes where permitted to use them, particularly in the 2 stroke days.
But certainly a conventional CVT set up is a pain in the arse to ride fast, but if everyone is on the same system, as always it's great racing.

I know several people over this side of the world have/are developing a system that gives more usable power delivery, but I have not personally seen a system that works in such
a way to negate the disadvantages compared to a conventional set up.

[Frits Overmars]

... I do wonder what would be if GP bikes where permitted to use them, particularly in the 2 stroke days.They would have been a lot faster, and easier to ride as well. I would have built one decades ago but the 'maximum 6 speeds' rule prevented it.
Don't be confused by a CT's tendency to drop the revs when you close the throttle and then come back with some lag when you open it again; that is only in-built behaviour to increase the acceptance for street-riding. Don't think either that the main advantage of a CVT is that it will handle narrow powerbands better. It will, but the character of a good racing engine doesn't need this.
The CVT's main advantage is that there are no shift-related power cuts while accelerating. And no, it's not about the tenths of seconds that the power is absent; it is all about keeping the gas dynamics in the engine on full song all the time. When you shift, power has to be interrupted for a moment (seamless shift boxes excepted) which means the exhaust pulses will stop. After a shift event the engine sound will return immediately, but engine power will not. It may take as long as a second before full power is restored. But chances are that you will have to shift again within that second. So on the track you will never have the power at your disposal that you saw on the test bench.
The efficiency of a common scooter CVT is about 10% worse than that of a shift box; it is caused by the friction of the rubber belt that must constantly be pulled from between the pully sheaves. Nevertheless such a CVT will give better results than a six-speed box in a comparable chassis. For racing, a steel transmatic belt like you'll find in several car transmissions would be the obvious choice; then a bike with a shift box could as well stay in the pits and save the petrol...

[jasonu]

Add to this that EVERY SINGLE tune up part, (with the exception of different weight rollers) come with the packaging "COMPETITION USE ONLY", yes, many people fit them on the road, however, this does not make them legal.

They are in no way eligible for buckets, I see no ambiguity in the rules that would allow this.


That pretty much ends the arguement (as long as it is true of course and I see no reason to think it is not) and makes all other 'Bucket application' points moot.

[Buckets4Me]

That pretty much ends the arguement (as long as it is true of course and I see no reason to think it is not) and makes all other 'Bucket application' points moot.

dosn't stop you copying them now dose it ?

[Frits Overmars]

dosn't stop you copying them now dose it ?My point exactly. Back in the day we made what we needed instead of buying it (makes me sound like an old fart, doesn't it?) Think Burt Munro, Jamathi, John Britten :first:

[richban]

dosn't stop you copying them now dose it ?



You would not need to build much at all. Just start with a standard one and make the rollers you need and the springs. Gilear 180 should be close to what you want. I will look today and see if I have any old vespa bits.

[SS90]

You would not need to build much at all. Just start with a standard one and make the rollers you need and the springs. Gilear 180 should be close to what you want. I will look today and see if I have any old vespa bits.

I expect someone will google some links shortly, but something you failed to mention is the variator face angles, belt width, and rear spring tension, I expect that the standard 180 Runner items are unsuitable for competition use.

I am unsure what the guys who raced the old European 180 Runner Cup used, but as far as I know standard transmission parts where generally not used, but I dont actually know.

Making a set of variator pullies would be quite some effort to get right (certainly not impossible).

Making rollers would be no real chore, just a little time consuming.

Like you say, a Gilera 180 Runner is possibly a good place to start, but while it is nice to see some innovation, is it not prudent to suggest that the current geared engine should be winning as is, it just needs to be made reliable, after all , the bikes that win have six speed boxes, and they have half time engines in them!

I was under the (perhaps) mistaken impression that Frits' FOC Cylinder was designed to be used a CVT of some description.

[TZ350]

A and B Grade Super Pole results. Best time 30.74. Clockwise.

273664 273665

The Mt Wellington 2-Hour run on Sunday was won by Dave M and Gary C riding a 2-Stroke prepared and tuned by Speedpro.

On Saturday in one of the North Island rounds Nate D was recording laps under 30's.

[wax]

I am kiwi s90 so the underarm was wasted on me.
There is a lot of things you can do with the std gear. The best torque driver for my bike is made by tgb as matter of fact it takes about ten minutes on the lathe to make it work. The stock clutch can be used ok its not as good but with heavier springs or lightened shoes you can really make it work well. The rollers can be simply drilled to reduce weight or used from another bike that uses the same engine. Its a very common engine. You could use just a air-cooled 125 cylinder replacement if you wanted there is a few around that make alot more power from a std style cylinder. The paiggio engine is so common in the scooter industry and it came out in so many different form that mix and matching to get what you want is very easy.
So what competition parts are you guys allowed to run. you have competition carbs and pipes on your bikes, is this where it ends
Im not saying anyone will do it. but it certainly would be awesome to see.

[SS90]

Yes, TGB have made pretty much all the OEM Piaggio variator componets in the last decade or so, and they seem to work especially well on the road, and last pretty well too.

What sort of work on the drive faces are you referring to? Do you just change the ramp angles? and how do you go about reducing the off/on drive train "lag" that is inherent in these systems.

I know that Malossi have the "Multivar" set up (competition use only), and that works pretty well , but these bikes have to have a transmission not manufactured for competition machinery.

[wax]

Malossi is not all it used to be infact I could show some pics of the rubbish they make these days. The different drive face angles are pretty much just fancy marketing. The angles don't change that mush between variators as much as they would like to
Market. The advance angle on the torque driver is different however. The tgb one is a good thing

[SS90]

Malossi is not all it used to be infact I could show some pics of the rubbish they make these days. The different drive face angles are pretty much just fancy marketing. The angles don't change that mush between variators as much as they would like to
Market. The advance angle on the torque driver is different however. The tgb one is a good thing

Im not convinced that the drive face angle are just a marketing thing, but ill keep an open mind. TGB (Taiwan Golden Bee) have made some high quality stuff over the last few years.

Most people in Europe that I know use Malossi, although, as you say, their quality has suffered, due most likely to their attempts to retain profit margins in a contracting market that is over subscribed. Stage6 also have some good torque drivers that seem to work well, but they retail at over €160, and that's alot of tin for anyone to handle.

Is the TGB torque driver you use designed for "competition use only" (I suspect the answer is yes), because making one would be a flippen headache, but, again, certainly not impossible.

[wax]

If you want to get rid of drive lag you set the transmission up correctly

[SS90]

If you want to get rid of drive lag you set the transmission up correctly

By "set the transmission up correctly", what do you mean exactly?

[wax]

Now your wanting me to give away secrets thats not going to happen..


Im not sure why you think that all the transmission pars are labeled competition only. There is heaps of parts for the transmission that's not competition only.

Even the mighty hit clutch is a road legal non competition part. But if your in competition I and your not running one your kidding yourself

[jasonu]

dosn't stop you copying them now dose it ?


My point exactly. Back in the day we made what we needed instead of buying it (makes me sound like an old fart, doesn't it?) Think Burt Munro, Jamathi, John Britten :first:

Absolutely and good luck to anyone that trys.

[SS90]

Now your wanting me to give away secrets thats not going to happen..


Im not sure why you think that all the transmission pars are labeled competition only. There is heaps of parts for the transmission that's not competition only.

Even the mighty hit clutch is a road legal non competition part. But if your in competition I and your not running one your kidding yourself

I have never heard of a "mighty hit clutch" I assume it's a brand named part?

I appreciate you don't want to divulge how to eliminate transmission lag in a conventional CVT system, but I am still to see one that doesn't have it ( and I have seen my fair share the last few years) and was hoping someone with experience could tell me how it's done.

With-out exception any aftermarket transmission parts (excluding rollers) I have seen come with a tech sheet clearly displaying "competition use only" for starters it is a way of contracting out of warranty and liability. The fact that 95% of the stuff ends up on the road is irrelevant.

[SS90]

Absolutely and good luck to anyone that trys.

Yes, I agree, running through in my mind what would be required for the whole project makes me shudder, but more power to anyone that tries.

Frits clearly knows that it is a winning concept, although I think that it would be a case of a solution looking for a problem, when you factor in how much effort is required.

[wax]

The hit clutch is a product made by dr pulley. It's half of the issue of getting rid of the lag. Im confused as to why it would seem like such a hard task. you have to mount the engine and thats really it. There is no gearshift clutch to work out. There is mutiple forums and sites about tuning this things. But lets see what other people come up with.

The tgb system is not a competition based unit. It comes out std on scooter they make.


I guess its easier to find fault in the idea than it is to actually do it. But the cvt is aproven system that works very well.

[richban]

Had a proper look at the dyno overlay today. Interesting for sure and a big help to see where we stand. I have 6 more at 8 and you have 6 more at 12. Now I am sure we can bring the gap closer at each end. I did feel having that drivability from low down on the small track was an advantage for sure. On Taupo that would be a different story. I would happily swap 6 hp from the bottom to the top. But saying that I did see the beast bite hard and launch another pilot into space right in front of me. Freaked me out for the whole race.

Anyway I must say thanks to you Rob and Cully for letting us pollute the workshop with the 4 strokes over the weekend. Storing the bikes there saved lots of hassle. Also for putting us onto Big J's Burgers. Best buggers ever. We stopped in at the Track in Tokoroa on the trip home. Looking at the length of the back straight I think the beast will be able to stretch its legs for sure.

Fun times.

[cotswold]

But saying that I did see the beast bite hard and launch another pilot into space right in front of me. Freaked me out for the whole race.
. We stopped in at the Track in Tokoroa on the trip home. Looking at the length of the back straight I think the beast will be able to stretch its legs for sure.

Fun times.[/QUOTE]

It freaked me out for the whole meeting, the beast bites hard for sure but with some carb tweeks it may yet suprise.

[husaberg]

They would have been a lot faster, and easier to ride as well. I would have built one decades ago but the 'maximum 6 speeds' rule prevented it.
Don't be confused by a CT's tendency to drop the revs when you close the throttle and then come back with some lag when you open it again; that is only in-built behaviour to increase the acceptance for street-riding. Don't think either that the main advantage of a CVT is that it will handle narrow powerbands better. It will, but the character of a good racing engine doesn't need this.
The CVT's main advantage is that there are no shift-related power cuts while accelerating. And no, it's not about the tenths of seconds that the power is absent; it is all about keeping the gas dynamics in the engine on full song all the time. When you shift, power has to be interrupted for a moment (seamless shift boxes excepted) which means the exhaust pulses will stop. After a shift event the engine sound will return immediately, but engine power will not.




but you may need a alternate method of starting the beast though TZ.

My initial thoughts were to use a CVT as well semi overdrive to overlap the gears.
it would of course have two problems it would have to be modded to only offer about a .75:1 reduction (not that hard limit the travel)and it would be near impossible to fit it on the primary drive with a conventional clutch set up still in place.
Whereas on the secondary drive it would spin about 1/3-1/6 engine speed (depending on what gear it was in)which may not be a bad thing.
Possible problems with the overlaping gear ratios principal would be you would know when to change as when the cvt od kicked in the rev counter would remain stationary........it also goes against the KISS principal
As a standalone unit the Salisbury unit on the Rokon offers a overall spread of ratios between 3.76 and .087:1.

If you read the article it says acceleration was not a issue......... although cornering on the tarmac might........

I thought my half backed mussing deserve some scorn (at least) heaped on them.

Now would this actually be a 6 speed or ten speed box.

1st 2.73
2nd 1.85
3rd 1.41
4th 1.14
5th 0.96

CVT timed to cut in at or near peak revs on output jack shaft as TZ mused. travel restricted to 0.75:1

1st 2.73-2.05:!
2nd 1.85-1.38:1
3rd 1.41-1.05:1
4th 1.14-0.88:1
5th 0.96-0.72:1 The gear ratios were chosen at random(cb350four i think) i guess TZ's GP are actually closer........

With these overlapping ratios there should be a lot less time off peak power.
Of course 5 gears would possibly be to many it should at least lessen the need gearshifting.

But a full CVT would be easier and legal (until proven otherwise provide the parts used were kosher...)


dosn't stop you copying them now dose it ? no or modding standard parts either


You would not need to build much at all. Just start with a standard one and make the rollers you need and the springs. Gilear 180 should be close to what you want. I will look today and see if I have any old vespa bits. to right.... or any other more suitable bits like those big scooters....

[kel]

the beast bites hard for sure but with some carb tweeks it may yet suprise.

Dont you dare, it took some serious tuning to get it to hit hard when opening the throttle. Its the BEAST not Grannies scooter.

[TZ350]

... a full CVT would be easier and legal ...

I agree, and as for the tune up goodies.

My thinking is that if the after market parts are marked, "For Racing Use Only" for marketing and legal reasons it does not nessacarily disqualify them.

Because if 95% of the components wind up in road going machines clearly the motivation for manufacturing the parts is to satisfy the customised road bike/scooter market and in reality they are just after market parts for the road that are good enough to be used in a race rig if you wanted to.

And its true TZ racing parts could be used in a RD road bike but that does not make them after market road bike parts because 95% or more of TZ parts were used in TZ road racers so clearly the motivation manufacturing those parts was to support racing competition.

Regardless of what the copy writers, legal beagles and add men say I think its the manufacturers target market that defines whether the part is an illegal race part or legal after market bling.

Anyway its a bit of a grey area and I will be interested in what others have to say.

[husaberg]

I agree, and as for the tune up goodies.

My thinking is that if the after market parts are marked, "For Racing Use Only" for marketing and legal reasons it does not nessacarily disqualify them.

Because if 95% of the components wind up in road going machines clearly the motivation for manufacturing the parts is to satisfy the customised road bike/scooter market and in reality they are just after market parts for the road that are good enough to be used in a race rig if you wanted to.

Its true TZ racing parts could be used in a RD road bike but 95% or more of TZ parts were used in TZ road racers so clearly the motivation manufacturing those parts was to support racing competition.

Regardless of what the copy writers and add men say I think its the manufacturers target market that defines whether the part is an illegal race part or legal after market bling.

Anyway its a bit of a grey area and I will be interested in what others have to say.

well here is my 10 cents. Plenty of off road bikes (that are not competition bikes.) like say crf50s's have stickers that say "not for road use"
i define the rule as it was written.



Engines must be derived from non-competition motorcycles.
Motocross, Road Racing, Enduro and Go Kart motors and transmission parts are not permitted.
But the the hot up clutch parts (assuming they are marketed as competition that is)are even a little grey for me...... plus not needed anyway.

Scooters seem to be a market that caters for shinny bolt on rather than DIY tuning so the market gets the parts that it wants.
If sketchy can make a Supercharger I am sure one of us can re-manufacture a CVT. or at the very least reverse engineer one.

[wax]

There is no need to put a gear box with the cvt as it has such a range it can handle from stop to full out. And it can hold the engine on it peak power the entire time. I can set my one uo ti have a 350 rpm varitation from take off to top speed. It takes time to get it this accurate but it makes them go well as well as makes the power delivery to the back wheel also very smooth. I have raced enough gearbox bikes and been right over in a corner on there back wheel and seen the distortion that goes through the bike when they change gear mid corner. There is none of that with a cvt.

Believe me there are plenty of parts you can get that are not marked track only. If you do decide to go down this route then pm me and I will let you onto some ideas on how to make a very reactive cvt that responds very hard

scootercentre.com have a look whats available and this is just one of the sites

[husaberg]

There is no need to put a gear box with the cvt as it has such a range it can handle from stop to full out. And it can hold the engine on it peak power the entire time. I can set my one uo ti have a 350 rpm varitation from take off to top speed. It takes time to get it this accurate but it makes them go well as well as makes the power delivery to the back wheel also very smooth. I have raced enough gearbox bikes and been right over in a corner on there back wheel and seen the distortion that goes through the bike when they change gear mid corner. There is none of that with a cvt.

Believe me there are plenty of parts you can get that are not marked track only. If you do decide to go down this route then pm me and I will let you onto some ideas on how to make a very reactive cvt that responds very hard

scootercentre.com have a look whats available and this is just one of the sites

I wasn't aware the stall speed (to use a car term) could be that high.
the musing about the gear box and CVT was to get around the FIM and formula 1 rule regarding number of gears (as Frits mentioned) which is mute
Why....... because they seem to have also banned two strokes anyway...........

plus freewheeling around corners would require some relearning for me.
If you have ever had a Ford Courier that pops out of fifth gear when you ease off the throttle you will know what i mean.
Having said that the kids on the MX50's don't seem to have a problem with it on the slipper clutch KTM's.......

[wax]

MY clutch comes in at 9700 on my 50. I set it up so that its coming in about 200 rpm into the power band t makes it launch off the line. Gearbox bikes dont have a chance against it in the drag to the first turn
And they don't freewheel around corners if you set them up with the right components. you can get a slipper clutch for them if you want to do that however.
Setting up a cvt takes a bit of work but when its done right the power is there and it is so smooth its awesome

[TZ350]

I don't know what type of scooter would be a good platform or where to buy a complete transmission engine unit from a wreaked one. I would be very interested in make/model suggestions and being pointed in the right direction to get a base unit to play with.

[speedpro]

I've put my Yamaha NXC125 scooter on the dyno. The power curve versus road speed is essentially flat for the range tested, 70-130Km/H. I'm using stock Yamaha transmission at the moment except for the higher final drive. It's so good with my motor I'm wondering what improvement could be made. There are plenty of aftermarket components for this scooter at least which aren't marketed as "race only". It helps to have a huge market for the bits mainly consisting of street ridden scooters.

They don't freewheel when the throttle is closed. What happens is that without load the CVT moves to the highest ratio meaning that essentially it shifts to top gear. Still not what you'd be used to on a shifter bike but I reckon you'd get round it no problem. What I like about the CVT is that in traffic you just twist the throttle and it shoots away, either at the lights or if you are already doing 80Km/H. That aspect of it would be awesome on a kart track.

Snow mobiles use a CVT transmission as well and the Canadians make all sorts of goodies good for up to 300+hp.

It wouldn't be ideal but I have wondered how it would go if a motorcycle swingarm was replaced with a scooter engine/transmission unit. Excellent tyres are available for the smaller wheels so that wouldn't be a problem.

[husaberg]

MY clutch comes in at 9700 on my 50. I set it up so that its coming in about 200 rpm into the power band t makes it launch off the line. Gearbox bikes dont have a chance against it in the drag to the first turn
And they don't freewheel around corners if you set them up with the right components. you can get a slipper clutch for them if you want to do that however.
Setting up a cvt takes a bit of work but when its done right the power is there and it is so smooth its awesome

ok i am intrigued if the clutch doesn't engage until 9700 how does the set up not freewheel then when the throttle is backed off for a corner?
when the revs drop below that level 9700rpm?

I used to enjoy road testing the DJ1 Hondas back in the day in the city as they would wheelie on the throttle which was unexpected on a 50 scooter.
On the other hand i wasn't a fan of the 8 inch front wheel though.

Not sure re the scooter re-engined bike. But as a sidecar project that would be interesting....

[speedpro]

It will disengage when the motor drops below the set revs. That was something I noticed on my scooter when I upped the gearing. The clutch disengages at about 35Km/H now, higher than it used to. Typically a scooter engine revs a lot lower than a screamer 50. You're right though. If you corner at a speed below that at which the CVT would be topped out in the highest ratio with no load, the engine revs will drop below the clutch engagement revs and it will disengage. Couple of problems there as noted including the possibility of the engine stalling. The one good thing about that is that if say the engine seizes it instantly drops below the clutch engagement revs and the clutch disengages. You only get a momentary wheel lockup then it freewheels. This I know from experiance.

[speedpro]

Rob and I have already talked about a sidecar with CVT, it'd be awesome though if you were using a whole scooter engine/transmission some sort of strengthening would be required to handle the loads when cornering though I already have that sorted in my mind. You'd let the front pivot flex a bit and have a seperate swingarm type of part connected to the standard scooter shock mounts via short adjustable rods using rose joints taking all the torsional loads rather than trying to resist them with the engine/transmission.

[husaberg]

Rob and I have already talked about a sidecar with CVT, it'd be awesome though if you were using a whole scooter engine/transmission some sort of strengthening would be required to handle the loads when cornering though I already have that sorted in my mind. You'd let the front pivot flex a bit and have a seperate swingarm type of part connected to the standard scooter shock mounts via short adjustable rods using rose joints taking all the torsional loads rather than trying to resist them with the engine/transmission.

I can't believe we are talking about sidecars without Kickaha..........

[Kickaha]

Rob and I have already talked about a sidecar with CVT,
Guy in Canada races a Sidecar which is powered by a snowmobile engine which must runs something like a CVT transmission

[Buckets4Me]

Guy in Canada races a Sidecar which is powered by a snowmobile engine which must runs something like a CVT transmission

I thought Guy was from england and raced a gsxr1000 ?

[TZ350]

273749

Garry and Dave, this years GP winners. The bike was prepaired and tuned by Speedpro.

http://www.flickr.com/photos/dty1/8216699544/sizes/z/in/set-72157632091510369/

[wax]

You have to remember that if the clutch is held against the bell and the bell is doing 10000 rpm then it will still stay out there. It doesn't care what it making it spin. Remember back I mentioned the dr pulley clutch it has a little ramp in it that pushes the shoes out against the bell and makes it stay in place until quite low in the rpm. well it will jump about 6500 to 7000 on mine. As soon as you gas it the motor just pulls up to what you set the cvt to and away you go. instant with no lag.
Its also very important to make sure that your torque driver (rear pulley) and the variator( front pulley) slide well so that they will change gear consistently. I lubricate my ones every race day with graphite powder, much like you guys do with the chain. when you set up a variator you need digital scales so you can be accurate. If you have a data logger it so easy. you just look at the rpm versus speed and make sure your rpm is constant. if it dropping then lighten up the weights as it getting to much load. If it rising then load up the engine.
Its really easy after a while

[wax]

Rob and I have already talked about a sidecar with CVT, it'd be awesome though if you were using a whole scooter engine/transmission some sort of strengthening would be required to handle the loads when cornering though I already have that sorted in my mind. You'd let the front pivot flex a bit and have a seperate swingarm type of part connected to the standard scooter shock mounts via short adjustable rods using rose joints taking all the torsional loads rather than trying to resist them with the engine/transmission.

or use a gp1 derbi engine
http://www.bikepics.com/pictures/2085857/
http://www.stuntbase.com/slikice/derbi_project/3.jpg

you can then use your normal swing arm

[TZ350]

I thought Guy was from england and raced a gsxr1000 ?

273751 273750

Guy Martin

<iframe src="http://www.youtube.com/embed/DFUYIH2Ttzk" allowfullscreen="" frameborder="0" height="315" width="420"></iframe>

<iframe src="http://www.youtube.com/embed/zbaO8mzByvw" allowfullscreen="" frameborder="0" height="315" width="560"></iframe>

<iframe src="http://www.youtube.com/embed/6wTK9dO9O5A" allowfullscreen="" frameborder="0" height="315" width="560"></iframe>

273752

[husaberg]

Weird i thought "Guy from England" was the last ever honest person to enter parliament.

Ended with flames also though

[Frits Overmars]

the musing about the gear box and CVT was to get around the FIM and formula 1 rule regarding number of gears ....A CVT is considered to offer an infinite number of transmission ratios between its lowest and its highest ratio.
You propose to use infinite plus five. Now that is definitely more than the maximum of six allowed by the FIM....


...They don't freewheel when the throttle is closed. What happens is that without load the CVT moves to the highest ratio meaning that essentially it shifts to top gear. Still not what you'd be used to on a shifter bike but I reckon you'd get round it no problem.
You need to know why it happens. Look at the picture of the secondary pully; you will see that the top heave is fitted to a bush with angled slots in it. The three pins in the picture fit through these slots into the secondary shaft, inside the bush. The heaves of the secondary pully are pushed towards each other by a spring (not shown) that fits around the bush.
Because of the angulation of the slots, comparable to a coarse pitch, the torque being transferred from the heaves via the slots and the pins to the secondary shaft, also tries to screw the heaves towards each other; this helps the spring.
Close the throttle and the torque is reversed; now the angled slots work against the spring; the heaves can be easily spread by the belt, the CVT 'shifts to a higher gear' and crankshaft revs drop; just what granny expects when she closes the throttle of her scooter.
For racing you want to keep the revs at max power rpm all the time; all you need is a stiffer spring and axial instead of angled slots. Simple as that.


...Its also very important to make sure that your torque driver (rear pulley) and the variator( front pulley) slide well so that they will change gear consistently.And it's important that the spring can rotate freely against the secondary pully. On the left of the picture you see a bush with a collar that fits around the bush with the slots, preventing the pins from flying away.The spring seats in this collar and often it is a tight fit. Removing the paint from the spring's bottom coil and polishing the bottom area will much improve the CVT's responsiveness.

[SS90]

A CVT is considered to offer an infinite number of transmission ratios between its lowest and its highest ratio.
You propose to use infinite plus five. Now that is definitely more than the maximum of six allowed by the FIM....


You need to know why it happens. just what granny expects when she closes the throttle of her scooter.
For racing you want to keep the revs at max power rpm all the time; all you need is a stiffer spring and axial instead of angles slots. Simple as that.
.

Thanks for that, are you saying that many of the aftermarket kits (like the Dr Pully Branded "Hit Clutch" that was mentioned earlier) are not necessary?
I only ask because it was mentioned that "if you don't have one, you aren't winning", and I wonder if these clutches are sold as an easier set up option to spring rates etc.

[Frits Overmars]

Thanks for that, are you saying that many of the aftermarket kits (like the Dr Pully Branded "Hit Clutch" that was mentioned earlier) are not necessary? I only ask because it was mentioned that "if you don't have one, you aren't winning", and I wonder if these clutches are sold as an easier set up option to spring rates etc.I can't say because I don't know anything about those kits. Maybe the slot angles are different, maybe the pully angles are different, maybe the pully diameters are different, maybe the sheave surfaces are different (sandblasting may help), maybe the springs that come with the kits are different.
And that is only considering the secondary pully. The centrifugal governor on the crankshaft, the belt itself, the rear clutch and the final gearing offer even more variables.
Nevertheless, making your own CVT is a lot simpler than making your own gearbox. I'm not talking about finding suitable shafts, clutch, gears, shift drum and forks; I'm talking about making them.
(It can be done; look at what Jan Thiel and Martin Mijwaart produced 45 years ago after their day jobs, with a third-hand milling machine and a worn-out lathe)

[SS90]

(It can be done; look at what Jan Thiel and Martin Mijwaart produced 45 years ago after their day jobs, with a third-hand milling machine and a worn-out lathe)

Every now and then someone reminds me that (by in large) many of us are spoiled to the point we forget that there is plenty of "guys in sheds" that make some amazingly good stuff with basic resources.

[wax]

The doctor pulley clutch is that just a clutch. It has nothing to do with the cvt torque driver or variator.

So it has nothing to do with the angles of the torque drive that frits is talking about. SS90 I cant help get the feeling by reading your posts your here that you have made your mind that its never going to work and your more intent on discrediting than learning

It may help to follow some of the links I post so it explains it better to you http://www.youtube.com/watch?v=h1BZP-31-Pg

[wax]

http://www.zumaforums.net/index.php/viewtopic.php?f=57&t=16564
these work very well to free up the spring and its the same thing I use on my scooter, Here is a link showing you how its done

[TZ350]

The full set of results from the 1st round of the Pacific Club North Island Series and the Two Hour including lap times.

[FastFred]

SS90 I cant help get the feeling by reading your posts your here that you have made your mind that its never going to work and your more intent on discrediting than learning

It may help to follow some of the links I post so it explains it better to you http://www.youtube.com/watch?v=h1BZP-31-Pg

Thanks Wax for your informative posts, you obviously know what your on about, and I think you have got SS90 figured.

[SS90]

The doctor pulley clutch is that just a clutch. It has nothing to do with the cvt torque driver or variator.

So it has nothing to do with the angles of the torque drive that frits is talking about. SS90 I cant help get the feeling by reading your posts your here that you have made your mind that its never going to work and your more intent on discrediting than learning

It may help to follow some of the links I post so it explains it better to you http://www.youtube.com/watch?v=h1BZP-31-Pg

Not at all, you may be being a little over sensitive, I'm just trying to get some information from someone that has experience, opposed to being sent to links, as I am of the opinion that information is best given from real world experience opposed to second hand information.

The ramp angles is something I mentioned earlier on, as I was lucky enough a few years back to have a very clever chap (working up the road at KTM) explain and draw me some images of how CVT style transmission (aspects of which are used in junior Motocrosss bikes) are in many ways superior, and the reason more development isn't done is simply because of market force (i.e the customers don't want it), but like many things, advantageous designs do actually catch on, evn if they come far far later than they were conceptualised.

Diescrediting you is mkst certainly not my aim, I am simply trying to get some concentrated discussion on how to get a CVT transmission working on a race bike that would make it superior (in a real world sense) to "conventional systems"

I have quite some experience racing in NZ and Europe, and in the last 6 years, plenty of that has been on scooters, some of which have been scootermatics, and the only guys that I have seen truly dominate (on scootermatics that is) have been feather weight string beans, put a beefier guy on one, and CVT transmission (from what I have seen) become difficult to set up, as you say, roller weights are a fairly straight forward affair, and Frits pointed out about rear springs ( the removal of paint I have seen, but didn't realise the true importance till now)

Using a GP1 engine fitted to a standard frame would seem like a good idea, but I can only see the problem of it being so damned long, it completely frigging your chain run, (critical in a conventional chassis) weight dispersal and so on (im not pissing on your idea here, just showing my opinion of why I am hesitant to say "wow, great idea")

I cant help but wonder if someone has gone to the effort of actually completing a GP1 engine in a chassis, and then raced it against a conventional bike, because if you could get the thing to handle, and least 2/3rds as well as a conventional bike, the advantages Frits has pointed out mean in your well in the game, perhaps even more than that.

Like I say, CVT equipped competition scooters, on tight tracks ,make for spectacular racing, and can (more often than not) show up conventional bikes, but, as far as I have seen, they can't cut it on the majority of tracks compared to conventional set ups.

Also, 30 P.S is heaps more than the winning bikes have, and they run shifter boxes, I cant currently see the need:scratch:

[husaberg]

I spent far to much time of the computer and came up with these.......
I does kind of beg the question those of starting a engine that has no electric starter or privision for a crankshaft kick i realise it can be got around but maybe best to start with one designed for the starter and the correct direction of rotation too i guess.

http://www.buggypartsnw.com/home?page=shop.browse&category_id=30

http://wqww.scooterfreaks.nl/forum/showthread.php?t=373412

http://blondesearch.ru/play/IyuC-LQE6Vk/Dr_Pulley_Variators_-_higher_angles%252C_more_take_off%252C_the_best.ht ml

http://highgaintuning.blogspot.co.nz/

http://battlescooter.com/37.html

http://www.hartmaninc.com/clutchtips.html

http://www.hondapcx.org/viewtopic.php?f=9&t=600&start=20

http://www.modernbuddy.com/forum/topic10793.html

http://flexistentialist.org/blog/archives/2003/10/27/cvt-basics-constant-variable-transmissions/

http://www.49ccscoot.com/lighten.html

http://www.49ccscoot.com/budget.html


http://www.youtube.com/watch?v=2VcdnM5l5b4&feature=player_embedded

I also came across this which was kind of funky http://www.suckindiesel.com/thingy/viewtopic.php?f=31&t=1242

All the ktm50s mx or trail up until the 2013 model were equipped with a two then three shoe clutch controlled by belvieu washers (cupped washers that serve as springs) or simple springs. no ramps

http://image.ec21.com/image/cometclutch/oimg_GC05197840_CA05334052/Ktm_50_Sx_Mini_Jr_Sr_Clutch.jpg
(the playbikes and mx earlier pre2002 had if i am not mistaken springs like a brakeshoe with a kind of a cam action in a way but not what we mean
http://image.ec21.com/image/cometclutch/oimg_GC05197840_CA05334066/KTM_50_Franco_Morini_S6_S6E_50cc_Lem_Husky_CLUTCH_ New.jpg
simple springs again up to 2009 on the sx's and the 2013 50sx has this.
http://i.ebayimg.com/00/s/NDUwWDM4Mg==/$(KGrHqV,!lEE5z7L7GPMBOmkpYBf(!~~60_35.JPG
the clutch is no more clever than the Dominator which has been around for well over 10 years......but was illegal in nz junior MX
http://www.r1dean.com/cart/images/dominator%20clutch-old.jpg
oh in 2009 they moved the clutch from the crankshaft and slowed it down a bit

[FastFred]

A CVT transmission looks like it has real potential .....

[Cheesy]

Hi Guys I have been searching through this thread (unsucessfully) for any of the GP100 port timings and modifications. If any have been posted could someone point me to the right page?
Thanks

[FastFred]

I have quite some experience racing in NZ and Europe, and in the last 6 years, plenty of that has been on scooters, some of which have been scootermatics,

That's good to hear, and Wax seems to know what he is on about, but as your more familiar with the Bucket racing rules maybe you could post something that contributes to sourcing legal parts or based on your own experience CVT tips and setup techniques.

[wax]

A gp1 runs in a chassis with a seperate swing arm. Had you looked at the links I have posted you would know this.

That's what I have been trying to say

[wax]

A well setup cvt does not care about the rider weight it will not aclerate as well due to the power to weight much like any bike. It's the same with a gearbox bike the lighter rider has the advantage as well.
If you put a heavier load on a cvt bike the engine will not be able to rev up and stay in a lower gear. The cvt changes gear by using a roller that flys out to change the gearing. It will make it stay in a lower gear longer. It just the same to setup for a light rider as a heavy rider. The setup changes when you change the engine setup not the rider weight

[SS90]

A gp1 runs in a chassis with a seperate swing arm. Had you looked at the links I have posted you would know this.

That's what I have been trying to say

A guy called Tony Foal (sp) makes a chassis design program that many consider the bees knees, if you manage to get a chance it is worth a look.

The problem I see with using the GP1 cases is that the sprocket is positioned on the end of the clutch shaft in (what is more or less) a standard CVT transmission case.

Putting this into a conventional chassis means your front sprocket position is going to be about a micky whisker away from where the swing arm pivot needs to be, unless of course you increase the angle the GP1 engine is mounted in, but this would put the engine crazy high in the frame, again detrimental to handling.

This is unfortunatey unusable in a conventional chassis, but in a GP1 chassis, where true handling and swing arm travel matter not, it's of little to no consequence.

maybe someone has an idea of how to design a CVT system that could work in a conventional chassis?

I personally don't. But would love to see someone that does!

Im not rubbishing you idea at all, just showing my opinion of why it's not the best solution, that would be making an entirely new set up that uses conventional cases, perhaps in a similar vein to how they convert wet clutches to dry, or how early unit construction stuff (the way Harley Davidson still do it) by having a separate primary drive case, that allows for a clever CVT design.

Take a look at Kart Sport, some classes have direct drive engines, you could cast your own cases (say like a KT100), have another rear case for the final drive gear and clutch set up, then connect the two with a CVT set up.

[teriks]

All the ktm50s mx or trail up until the 2013 model were equipped with a three shoe clutch controled by belvieu washers (cupped washers that serve as springs) or simple springs. no ramps

Yup, no CVTs there, but terribly maintenance intensive centrifugal cluches.. witch reminds me I got work to do.

[jasonu]

I agree, and as for the tune up goodies.

My thinking is that if the after market parts are marked, "For Racing Use Only" for marketing and legal reasons it does not nessacarily disqualify them.

Because if 95% of the components wind up in road going machines clearly the motivation for manufacturing the parts is to satisfy the customised road bike/scooter market and in reality they are just after market parts for the road that are good enough to be used in a race rig if you wanted to.

And its true TZ racing parts could be used in a RD road bike but that does not make them after market road bike parts because 95% or more of TZ parts were used in TZ road racers so clearly the motivation manufacturing those parts was to support racing competition.

Regardless of what the copy writers, legal beagles and add men say I think its the manufacturers target market that defines whether the part is an illegal race part or legal after market bling.

Anyway its a bit of a grey area and I will be interested in what others have to say.

If you allow some parts that are marketed as competition or race use but not others you are opening a huge can of worms. If, for any reason, a part is sold as a raceing part then it should be excluded with no questions asked.

[Grumph]

If you allow some parts that are marketed as competition or race use but not others you are opening a huge can of worms. If, for any reason, a part is sold as a raceing part then it should be excluded with no questions asked.

Lets clarify this a little - motor parts are free rein so long as you're fitting them to a road derived motor...transmission and gearbox parts from competition bikes or sold as competition parts are not legal.
Whether the Euro companies are saying "not for road use, competition parts" to cover their arses legally or not is irrelevant...if the package says competition part and it's for gearbox or transmission - not legal in this class.
As Frits says - make it yourself.

[kel]

If you allow some parts that are marketed as competition or race use but not others you are opening a huge can of worms. If, for any reason, a part is sold as a raceing part then it should be excluded with no questions asked.

"Engines must be derived from non-competition motorcycles. Motocross, Road Racing, Enduro and Go Kart motors and transmission parts are not permitted"

Jasonu, I don't believe your interpretation stacks up with the rule as it written. In my view Its only when the specific wording "for competition use only" is applied to parts for NON COMPETITION ENGINES can these parts then be considered as "not permitted" (a lawyer would comfortably push it further). There are literally hundreds of aftermarket "race" parts for road going Aprilia 50's and the like. Generally the labelling is for marketing hype rather than application, the brand names Simonini Racing and Top Performance spring to mind.
There are numerous hot fifties being built at this time, I dont for one moment imagine they'll be running original cylinders, why would they?

[kel]

Whether the Euro companies are saying "not for road use, competition parts" to cover their arses legally or not is irrelevant...if the package says competition part and it's for gearbox or transmission - not legal in this class.

No, thats not how the rule is written either.

[Grumph]

"Engines must be derived from non-competition motorcycles. Motocross, Road Racing, Enduro and Go Kart motors and transmission parts are not permitted"

There are numerous hot fifties being built at this time, I dont for one moment imagine they'll be running original cylinders, why would they?

Correct - and perfectly legal if the basis of the build is a non competition motor - but use a close ratio box marketed as a competition part for a race variant of that motor,and no, that's not legal....

some of you are apparently unable to read the rule as it is written.....

[kel]

Correct - and perfectly legal if the basis of the build is a non competition motor - but use a close ratio box marketed as a competition part for a race variant of that motor,and no, that's not legal....

some of you are apparently unable to read the rule as it is written.....

Race variant? Did Aprilia ever sell or market as such? Aren't all racing Aprilia 50's converted from AM6 or euro non competition motors?
I can read the rule perfectly well, the parts you refer to have to be from "Motocross, Road Racing, Enduro and Go Kart motors"
My earlier interpretation errs on the side of caution, if we want to take it the letter of the law as written ...

[TZ350]

Thanks for the tips.


or use a gp1 derbi engine
http://www.bikepics.com/pictures/2085857/
http://www.stuntbase.com/slikice/derbi_project/3.jpg
you can then use your normal swing arm


... it's important that the spring can rotate freely against the secondary pully. ... Removing the paint from the spring's bottom coil and polishing the bottom area will much improve the CVT's responsiveness.


http://www.zumaforums.net/index.php/viewtopic.php?f=57&t=16564 these work very well to free up the spring and its the same thing I use on my scooter.

273804 pictures taken from a link Wax posted

A useful looking fan there, that could be used for a bit of forced air cooling like Grumph suggested I should look at.

273805 2005 Derbi GP1 picture taken from a link posted by Wax

Wax could you please give me the length from the center of the crank to the center of the drive sprocket.

273806

I expect there are shorter belts available so the CVT transmission could be shortened if needs be but there is plenty of room in my chassis so the Derbi GP1 or something similar might just slot in as is.

Fitting the Derbi GP1 CVT engine assembly or the Beast engine less gearbox and fitted with a CVT transmission into my frame could do two good things, put the sprocket closer to the swing arm pivot and put more engine weight on the front wheel for better weight distribution.

Even better I could get one of those performance aftermarket 100cc H2o road cylinders and maybe even fit it to a home made center mounted rotary valve crank case.

CVT has possibilities.

[jasonu]

"Engines must be derived from non-competition motorcycles. Motocross, Road Racing, Enduro and Go Kart motors and transmission parts are not permitted"

Jasonu, I don't believe your interpretation stacks up with the rule as it written. In my view Its only when the specific wording "for competition use only" is applied to parts for NON COMPETITION ENGINES can these parts then be considered as "not permitted" (a lawyer would comfortably push it further). There are literally hundreds of aftermarket "race" parts for road going Aprilia 50's and the like. Generally the labelling is for marketing hype rather than application, the brand names Simonini Racing and Top Performance spring to mind.
There are numerous hot fifties being built at this time, I dont for one moment imagine they'll be running original cylinders, why would they?

Mate, I think the rule is perfectly simple to understand/interpret UNLESS one is looking for loopholes ie the infamous 'and' between the words motors and transmission. Weather the labelling is for hype or summat else if it includes words like race part or off road only etc then it should not be allowed.
I don't know anything about the 'hot 50's' you mention but if anyone has an issue with them or anyother bike surely a protest should be lodged to get an official decision (unlike what happened with Forzagate...)
When I was involved with the class it all seamed pretty straight forward. Roadbike/commuter/homemade engine/trans parts were ok, MX/enduro/roadrace engine parts were not. You remember those days don't you?

[husaberg]

Yup, no CVTs there, but terribly maintenance intensive centrifugal cluches.. witch reminds me I got work to do.

yeah been there. hate them the (belvieu washer models) with a vengeance.even though they are incredibly tunable.
Although the 09 and later are "supposedly maintenance free" other than changing the oil each meeting. So they say.
The Dominator and the 2013 do have ramps though. All the slipper 50's are fast on the mx tracks and get of the line better than the 65's.

I am not getting involved in the normal rule shit fight this time..........
Other than to say i can read what they say, rather than what people think they say.
To save the inevitable shit fight i have gone out of my to stay inside the average blokes interpretation of the rule rather than the actual wording.

[kel]

When I was involved with the class it all seamed pretty straight forward. Roadbike/commuter/homemade engine/trans parts were ok, MX/enduro/roadrace engine parts were not. You remember those days don't you?

Sure do, and thats exactly what exists today. Two words - DD50, Malossi. But lets leave it there or we'll upset Mr TZ.

edit: better explain that before its interpreted the wrong way; the mans bike has a Malossi set up and its legal. Plenty of people want to argue if its Malossi it shouldn't be allowed - it is!

[jasonu]

Sure do, and thats exactly what exists today. Two words - DD50, Malossi. But lets leave it there or we'll upset Mr TZ.

Fair call.

[wax]

Thanks for the tips.







273804 pictures taken from a link Wax posted

A useful looking fan there, that could be used for a bit of forced air cooling like Grumph suggested I should look at.

273805 2005 Derbi GP1 picture taken from a link posted by Wax

Wax could you please give me the length from the center of the crank to the center of the drive sprocket.

273806

I expect there are shorter belts available so the CVT transmission could be shortened if needs be but there is plenty of room in my chassis so the Derbi GP1 or something similar might just slot in as is.

Fitting the Derbi GP1 CVT engine assembly or the Beast engine less gearbox and fitted with a CVT transmission into my frame could do two good things, put the sprocket closer to the swing arm pivot and put more engine weight on the front wheel for better weight distribution.

Even better I could get one of those performance aftermarket 100cc H2o road cylinders and maybe even fit it to a home made center mounted rotary valve crank case.

CVT has possibilities.
Your welcome

http://www.sprocatti-motori.com/Carter_disco_scooter_Piaggio.htm ( doesnt say competition only either)

This is a long and a short case piaggio I can find out the lengths for you if you wish.

There are electric start models or kickstart models available as well. There is so much stuff for these engines it will blow your mind

http://www.sprocatti-motori.com/index.htm

[TZ350]

This is a long and a short case piaggio I can find out the lengths for you if you wish.

Yes I would love to know the lengths.

And thanks for the links to the pictures.

273809


If for any reason, a part is sold as a raceing part then it should be excluded with no questions asked.

...if the package says competition part and it's for (Engine) gearbox or transmission - its not legal in this class.
http://www.sprocatti-motori.com/Carter_disco_scooter_Piaggio.htm

273811273810

I cant see any mention of "Race" or "Competition" any where so these would be legal.

I particularly like the cylinder, its 50mm the Beast could be getting an upgrade.

[bucketracer]

Back in the day we made what we needed instead of buying it . Think Burt Munro, Jamathi, John Britten :first:

Maybe on a smaller scale but in their own way, TeeZee, Crazyman (frames), Chambers, Speedpro, F5 Dave the list could go on for pages.


Every now and then someone reminds me that ... there is plenty of "guys in sheds" that make some amazingly good stuff with basic resources.

Thats so definitely TeeZee ...

[bucketracer]

273805 2005 Derbi GP1
picture taken from a link posted by Wax

273806 FZR 3LN Chassis

... there is plenty of room in my chassis so the Derbi GP1 or something similar might just slot in as is.

It sure looks possible.

[bucketracer]

Hi Guys I have been searching through this thread (unsucessfully) for any of the GP100 port timings and modifications. If any have been posted could someone point me to the right page?
Thanks

273858

Chambers made a 22rwhp GP100 but there was not much posted about it. It had a big carb and at the time it made more hp than TeeZees 125.

273867

The whole thing was an experiment to see if a big carb 100 would be a better bet than a restricted 125.

273868

The 100 had only one real outing, at Taupo and showed its gratatude by spitting Chambers off leaving him with a nasty bruise.

And in the next race Av rode it, and it spat her off in the same corner too, after that Team ESE made new bikes using FZR 3LN chassis with GP125 engines.

If I come across anything I will PM you.

[wax]

It sure looks possible.

It would be great to see some one do it. Would sound awesome on the track and it would be quick. It would have 100% of the power 100% of the time the throttle is opened

[husaberg]

273806

I expect there are shorter belts available so the CVT transmission could be shortened if needs be but there is plenty of room in my chassis so the Derbi GP1 or something similar might just slot in as is.

Fitting the Derbi GP1 CVT engine assembly or the Beast engine less gearbox and fitted with a CVT transmission into my frame could do two good things, put the sprocket closer to the swing arm pivot and put more engine weight on the front wheel for better weight distribution.

CVT has possibilities.

Open question to crazyman
How much to mount the MC16 frames Rob has in your frame jig and reconfigure to NX4 geometry.......

<img src="http://www.motoacademy.co.nz/assets/Images/_resampled/resizedimage368276-DSC03155.JPG" height="340px"/><img src="http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=273863&d=1326352786" height="340px"/>


Not that i don't think the CVT could be excellent.
just wondering..........

[Frits Overmars]

...Wax could you please give me the length from the center of the crank to the center of the drive sprocket. I expect there are shorter belts available so the CVT transmission could be shortened if needs be but there is plenty of room in my chassis so the Derbi GP1 or something similar might just slot in as is.
Fitting the Derbi GP1 CVT engine assembly or the Beast engine less gearbox and fitted with a CVT transmission into my frame could do two good things, put the sprocket closer to the swing arm pivot and put more engine weight on the front wheel for better weight distribution.
CVT has possibilities.Seems we've wetted your appetite, TeeZee. Tip: take a look at the Derbi Variant MJR: http://www.50soffroad.net/web/foro_offroad/viewtopic.php?f=70&t=11

And just look how simple the cases are compared to those of a gearbox engine. This is something you can definitely make at home.

[Frits Overmars]

Apparently I can only upload six pictures at a time. Here are the two that got left behind.

[FastFred]

Using a GP1 engine fitted to a standard frame would seem like a good idea, but I can only see the problem of it being so damned long, it completely frigging your chain run, (critical in a conventional chassis) weight dispersal and so on

It looks like a CVT with a chain final drive fits in a conventional frame layout ok.

273879 273907


I have quite some experience racing in NZ and Europe, and in the last 6 years, plenty of that has been on scooters, some of which have been scootermatics,

It doesn't show in your posts, so I wouldn't make a virtue of it as people will expected some real technical insight from someone touting that sort of background.


I am of the opinion that information is best given from real world experience opposed to second hand information.

SS90 maybe if you relied less on your own and a few friends limited personal experience and did more research educating yourself, internet based and otherwise like TeeZee does you would be more successful in what you do and be able to contribute actual ideas with a more positive input, its just a thought.

[Cheesy]

273858

Chambers made a 22rwhp GP100 but there was not much posted about it. It had a big carb and at the time it made more hp than TeeZees 125.

273867

The whole thing was an experiment to see if a big carb 100 would be a better bet than a restricted 125.

273868

The 100 had only one real outing, at Taupo and showed its gratatude by spitting Chambers off leaving him with a nasty bruise.

And in the next race Av rode it, and it spat her off in the same corner too, after that Team ESE made new bikes using FZR 3LN chassis with GP125 engines.

If I come across anything I will PM you.

Cool thanks for that, I bought a GP100 bucket off trademe for spare parts for a commuter but it does actually go (now) and is much faster than the road going version so it could be fun to play with. Some one has had a little go at porting it but not anything too significant other than a small auxiliary exhaust port that has been drilled in, has what I assume to be an RGV250 pipe on it and a bored out Mikuni flatslide. All I have done so far is modify what I assume to be a GP125 head with a squish band and toroidal chamber

[crazy man]

Open question to crazyman
How much to mount the MC16 frames Rob has in your frame jig and reconfigure to NX4 geometry.......

<img src="http://www.motoacademy.co.nz/assets/Images/_resampled/resizedimage368276-DSC03155.JPG" height="340px"/><img src="http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=273863&d=1326352786" height="340px"/>


Not that i don't think the CVT could be excellent.
just wondering..........nice to know the angle from the frame rails to the fork head ? maybe close as it stands if it had the same lenth forks as a rs in it.. so would end up most the work would be in the swing arm pivit

[TZ350]

take a look at the Derbi Variant MJR: http://www.50soffroad.net/web/foro_offroad/viewtopic.php?f=70&t=11
And just look how simple the cases are compared to those of a gearbox engine. This is something you can definitely make at home.

Thanks for the pictures.


Seems we've wetted your appetite...

Yes, to true, but things take time ....

I remember your comment about my engine placement and how it could be changed to good effect handling wise and that would improve lap times. Well we took it to heart and have been working on it. We are constructing a completely new bike, in the mean time we have been keeping the old one going so there is something to ride and use for engine testing and development.

Also your original comments about CVT's had me thinking about how they could be used to eliminate wasteful gear changing and improve drive out of the corner which is where my bike looses out to the FXR's. At Mt Wellington, its those first few bike lengths out of the corner that are so important.


The CVT's main advantage is that there are no shift-related power cuts while accelerating. And no, it's not about the tenths of seconds that the power is absent; it is all about keeping the gas dynamics in the engine on full song all the time. When you shift, power has to be interrupted for a moment (seamless shift boxes excepted) which means the exhaust pulses will stop. After a shift event the engine sound will return immediately, but engine power will not. It may take as long as a second before full power is restored. But chances are that you will have to shift again within that second. So on the track you will never have the power at your disposal that you saw on the test bench.

Thanks Frits, and that is why I am interestd in CVT.

At the last meeting at Mt Wellington I did not see any bike actually overtake the Beast down the straight but a few kept up with it by virtue of there better initial drive. Then a more skilled or experienced rider could out ride the Beast on the approach to the next corner.

273911

I think there is plenty of room in my frame for a CVT and chain final drive and the CVT could be incorporated into the engine plates.

I only need the main components from something that can be tuned to peak at about 12-13k. It would be easy to cut the gear box of the beast and run it with a CVT transmission. Although I would probably look at making something entirly new like a H2o 100 with a rear mounted rotary valve and special pumper slide carb.

All I need to know is what to get that is legal for my class of racing, and where to go to get it. Speedpro suggests something Yamaha from Malaysia as he tells me there are plenty of tuning parts for road scooters and bikes that don't have the illegal words "Racing" or "For Competition use Only" printed on the packaging.

What I would like is the complete bottom end and transmission from a blown up wreck, four or two stroke, it doesn't matter so long as I can get several of them for development and spares.

Now does anyone have a couple of discarded CVT engine/transmissions lying around they can sell. If they are boxed and labeled I can pretty much get them picked up from anywhere in the world.

[wobbly]

I will say it AGAIN TeeZee, forget that shit.
Spend your time perfecting a 30Hp 125 Aircooled that has superb throttle response, can kick NoMates arse - who still holds the lap record at Mt Welly - and runs all day, every day.
THEN fuck with off the wall ideas, especially ones that will see the thing spinning at 13000 nearly ALL the time..

[TZ350]

I will say it AGAIN TeeZee, forget that shit.
Spend your time perfecting a 30Hp 125 Aircooled that has superb throttle response, can kick NoMates arse - who still holds the lap record at Mt Welly - and runs all day, every day.
THEN fuck with off the wall ideas, especially ones that will see the thing spinning at 13000 nearly ALL the time..

Basically that is the plan, as we are still developing the Beasts engine and the new bike is being built for improved handling. It will be able to run a conventional engine or CVT or mix and match both as it will be setup for easy engine swaps.

Anyway I only think about this stuff and future development plans when I can't get any dyno time for the Beast and have to amuse myself with something else.

[richban]

I will say it AGAIN TeeZee, forget that shit.
Spend your time perfecting a 30Hp 125 Aircooled that has superb throttle response, can kick NoMates arse - who still holds the lap record at Mt Welly - and runs all day, every day.
THEN fuck with off the wall ideas, especially ones that will see the thing spinning at 13000 nearly ALL the time..


I sort of agree here.

Depending on how it was designed I could imagine you may end up adding 6 to 10kg to the bike weight with drive shafts and transmission parts. Those clutches and variators are heavy. And they would need to be to take the power. Then you will need to connect it all to the wheel again. Not sure on the power losses you would get through the trans, that alone might make the thing a know go. In saying that I have bits for you if you want.

[husaberg]

nice to know the angle from the frame rails to the fork head ? maybe close as it stands if it had the same lenth forks as a rs in it.. so would end up most the work would be in the swing arm pivit

Yeah from memory the mc16 fork are fairly short (but probably very much longer than a NF4 STD) but the head angle is way lazy as std on the MC16.
the major is taking out the extra 3 or so inches of spar length head angle can be tidied up with incerts if nes (as the head bearings are beafy)

it was an impossible to answer question.
My plan before i brought the NF4 frame.
was just to flip a nx4 frame upside down get the head angle positioned at ninety degrees the make another two vertical posts that would have a hole drilled for the position of the swingarm pivot.
then position the nsr frame in the basic jig upside down off course and hack out the spars to suit if that makes sense.
but seeing as you already have a substantial jig...................
the jig would look kind of like this only not be a pushbike and be upside down:facepalm:

http://t1.gstatic.com/images?q=tbn:ANd9GcSL_E25d2lQepoGq8MXx-YUKko-16qArJgvVp-pX2LS14uB1gE0L0xBBkkjQQ
I would assume that acuallly fairly close to how the Japanese actually manufacture the frames after the intitial frame is built.
maybe sir Stephen (our Japanese based corespondent) can confirm this

[jasonu]

, can kick NoMates arse - and runs all day, every day.
..

That is not what I have heard/read/seen/been told. Lots of let downs and blowing up is the way I understand that bikes history.

[TZ350]

nice to know the angle from the frame rails to the fork head ?

Mindful of the parallax error.

273919 273920 Zero for an early RS

273921 273918 7 deg for a NF4

273922 273917 5 deg for a MC16

It is the MC16 frame I am going to use. I have a complete RS250 front end for it and a magnesim 3.5x17 front for the rear and a light weight RS125 copy tank so I hope to be able to keep the weight down.

[husaberg]

Mindful of the parallax error.

273919 273920 Zero for an early RS

273921 273918 7 deg for a NF4

273922 273917 5 deg for a MC16

matches this representation of a MC? not sure which model but i will check....looks like mc18 from here which is well worth a look at the blog.....
http://edetuckracing.blogspot.co.nz/

[Buckets4Me]

I sort of agree here.

Depending on how it was designed I could imagine you may end up adding 6 to 10kg to the bike weight with drive shafts and transmission parts. Those clutches and variators are heavy. And they would need to be to take the power. Then you will need to connect it all to the wheel again. Not sure on the power losses you would get through the trans, that alone might make the thing a know go. In saying that I have bits for you if you want.

sounds like you are getting scared :) . It might way nearly as much as an fxr and have lots more power with no need to change gears :Punk:

[wax]

Actually the whole setup would be lighter as there is not the same amount of steel gears.
The variator is made out of alloy.
There isa few gears in the back but as its only one gear its alot less

Total weight with oil is 17kg

http://www.minarelli.com/prodottieng.html

seems a sweedtech cr125 is 16.7 kilos

Im not sure how this compares to the engines you guys are running but I would say its close if not a bit lighter being a competition engine

http://www.swedetechracingengines.com/moto_honda_125cc_engine.html

Im not sure what the gp1 engine weighs but it shorter then the one i posted so I would guess its at the same if not less

High rpm will be fine the cranks are developed to handle it just fine.
The aftermarket parts will handle it just fine. You will need to change the belts every 1000k to keep the top performance from your engine. As they wear it changes there angle of attack on the variator

[richban]

sounds like you are getting scared :) . It might way nearly as much as an fxr and have lots more power with no need to change gears :Punk:

Yeah, but nah. My bike is making more ponies where it counts for kart tracks, she corners and generally is the shit. So nah. Tokoroa will be the beasts best chance to wind up. It has a nice long back straight. I have raced auto scooters and I can tell you now on a tight kart track I would go with the gears all day long. When you try to turn in a bike with no engine breaking at all, its the rear break and nothing else that gets it done. And with instant 30hp on tap good luck not hi siding that one. Yes you can adjust your riding style but I don't think it would be any advantage. To get the hole shot every race (which it could) you would have a bike that would bite so hard out of the corners you would be shitting yourself for sure. I am sure things have moved on with clutches and so on but I can't see how you could tune it for mega starts and also better power delivery out of corners. Happy to be proved wrong.

[wax]

Are you kidding hole-shots is what the cvt will give you.

The cvt is a weapon off the line. We were up against 85cc cr powered race bikes. You would holeshot them from back on the 2nd row.
I know mount wellington track I used to race kt100s on there. The cvt anillate will the gearbox bike into the top corner and you will end up playing from then on in.

You have to remember that you tune the cvt for the power of your engine so it will do both haul out of corners as well as off the line.
You can hold your engine on its power peak the entire track and at any speed if you can make the corners.

Your sitting on the power peak the whole time. If you tune a cvt wrong its easy to hold it on it the down slope of the rising slope as well and make a 30hp engine go like a 5hp engine if that where your holding the revs.

It would go great on the long tracks you would just have to change the sprockets on the chain. But that would be the same for the geared bikes

http://www.youtube.com/watch?v=x3UpBKXMRto

Awesome in the rain due to the smoothness as well. And it is new zealand after all. its going to rain

[richban]

Are you kidding hole-shots is what the cvt will give you.

The cvt is a weapon off the line. We were up against 85cc cr powered race bikes. You would holeshot them from back on the 2nd row.
I know mount wellington track I used to race kt100s on there. The cvt anillate will the gearbox bike into the top corner and you will end up playing from then on in.

You have to remember that you tune the cvt for the power of your engine so it will do both haul out of corners as well as off the line.
You can hold your engine on its power peak the entire track and at any speed if you can make the corners.

Your sitting on the power peak the whole time. If you tune a cvt wrong its easy to hold it on it the down slope of the rising slope as well and make a 30hp engine go like a 5hp engine if that where your holding the revs.

It would go great on the long tracks you would just have to change the sprockets on the chain. But that would be the same for the geared bikes

http://www.youtube.com/watch?v=x3UpBKXMRto

You miss understand me. I said you could hole shot every race. I just don't like corning the things and the power delivery out of corners, in my experience was a little unpredictable depending on the speed you were cornering.

[richban]

Page 650....

[wax]

oh ok sorry.

The strange power delivery out of corners is caused partly by a slipping clutch. which is why the doctor pulleys are so good.
Also as frits said to weak a torsion spring and it holds it up in the gears. By putting the right spring in the back it down changes correctly and so its in the right gear all the time.

Also you need to keep it lubricated so it can change the gears correctly. The weak point in a cvt is if it gets sticky it will not change gear correctly. Anyone who has ridden a road scooter will know that when you ride along and then back off and then gas it again its slow to pickup like its in to high a gear. You can stop on the side of the road and then gas it again and it will downshift. There is ways to get around this lack of downshift and it makes them come alive.
A doctor pulley clutch will not release in the corners and will give you a positive lock this gets rid of the mushy cvt feeling.

[TZ350]

Starting from the beginning I have been trying to find the posts that talk about pipes and collate and edit them. There is heaps of it and pages 620 630 and 640 have un edited collections of raw material.


Not really. The RSA's TDC crankcase volume is 675 cc (for a 125 cc engine!) but most of this volume is in the transfer ducts. Over the years Honda has produced cylinders with and without the lip that your picture shows, sometimes both types in the same production year. But flow through the C-port is not the most important item of a fast cylinder.
Another point to help you make up your mind: compared to a Honda RS125 or RS250 the Aprilia RSA125 produces about 20% more power per cylinder....


Re EngMod2T question on ducts and entry areas.
Depends upon the geometry of the duct in the case and that of the cylinder where the duct begins at the bore edge.
In many designs the inner wall is very short ( above the gasket plane ), and the case extension of the duct outer wall drops away very sharply - with the floor being miles away from the gasket plane.
In this case I would use the area/length at an angle from the bore edge out to just below the gasket plane.
Some engines have a longer inner wall, and also have the case floor close to the gasket surface.
In this design the duct really does "go around the corner" into the case and the ( vertical ) window forms the entry area, as shown in the help files.
Truth be known the main effect is to change the case volume, but this spec is always MUCH better to model accurately by drilling a hole in a piston at TDC, and calculating with the ducts included.
The case volume total has a bigger effect on the real power produced by the sim, rather than duct length.
Duct length, has a bigger effect on the sim run times, not power.
I tried to replicate the run time error as you found TeeZee, and yes my system does the same - I never found that issue as I have never changed the zero figure before.
None of the pipes I have done have a "step", always an oval to round transition in the flange, that is modelled as a short taper in the pipe screen.
So yes, send a report to Neels, it is a "fault".
He is working now on creating a "button" that will collect all the files used by a project, into one file, so its easy to send each other sims to check, making it much quicker for others to review projects already created.

Re Ignitech starting issues, and base advance.
Post up a screen shot of the "Bike" page and advance curve, I may be able to help with that.


The backward angle of the port flank nearest the exhaust (the green line in your drawing) is important, but I agree that your duct is not a thing of beauty.
But the right-side duct, though it may look more attractive, is even worse. The backward angle of the green line may be somewhat exaggerated, but the blue line is not sufficiently angled backward, which will result in short-circuiting: fresh charge from the A-ports will make a U-turn and escape directly into the exhaust duct. And it will do so as soon as the transfer ports open, which means it will be too far down the exhaust pipe by the time the return pulse tries to shove escaped charge back into the cylinder.
I can only guess as to the purpose of such a design. Maybe it is not even a deliberate design but just the result of using existing casting cores for a new cylinder.
Or maybe the cylinder studs were in the way...

By the way, I appreciate you calling me Mr. Frits, but there is no need; just Frits will do fine .

Remember what I said about those simple calculations: they are only meant to help beginning tuners on their way and a lot of more or less important facors, like compression ratio, ignition timing, type of fuel, carburetter diameter, crankcase volume and angle*areas, are not taken into account.
In your example the important thing is that lower exhaust timings need bigger header diameters. But explaining why this is so, might be beyond the scope of this forum (and it would certainly be beyond the time I have at my disposal).
But come to think of it: the least I can do is post the same simple calculations here. Instead of all those factors I left out, I included one variable, the speed of sound. Starting with 550 m/s will get you in the right ballpark, after which you can vary this value according to your findings.
Final remark: the calculation of the tailpipe restrictor diameter is critical: you can only apply it to engines that are thermally sound. Air-cooled engines are not...


Here is a comb file for a very fast RS125, where the sim is all but perfectly reflecting reality.
The difference between the sim and RWHp is around 10 to 12% as you would expect - despite what many say about the fudge factors in a Dynojet.
The comb file has afr as measured on the dyno - and shows the correction of the ratio naturally going rich over the pipe, by the powerjet switching at 12200.
Without the powerjet it would go very rich, and would not make any power past 12600 - as in reality.
But for most sims, you will be in the ballpark simply running 12:1 in all fields.
The comb efficiency is good for full house racing 2T at 0.92,less well tuned engines will be down between 0.87 and 0.9
And the combustion variables are as calculated by the program using the turbulent model - you use burnrate prescribed until the model is well refined,then run turbulent ( very slow)
and transfer the results from that run manually,to speed up later sims by using real burnrate numbers.
Re the question of cylinder temp.The important factor is TUbMax - the temp of the end gases trapped in the squish.Optimum is around 1000*, but if its too high, the sim will automatically
show a warning on the screen - "deto" as the run is progressing.
Too lean, and or too much timing or compression and this warning comes up, believe it and change something to fix it, or your computers piston will sieze.
PS - I need your .pjt file to make it easy to open the sim.
Neels is working on a "pack and go" button that will collect all files for a project and put them in one file to send out for review.

Re the A and B port stagger.
Honda have always run the A port higher approx 0.7mm giving timings of 132/130/129.
This works OK using the big T port,but in the Aprilia 3 port layout, when pushed to the extreme as Jan did, the A port is lower to allow more area for the huge Aux ports needed to give sufficient blowdown.
Then the B port is raised to get back the needed transfer TA.

Re the ignition problems at starting.
Two things, firstly reverse the wires from the trigger and delete the reverse polarity button in software.Many times the trigger wired backwards gives very odd results when strobed.
Secondly, look at the "number of programmings" no way have you done 33,000 changes - this means the ECU is being corrupted by RF noise, you need to check the resistor plug cap and plug, as well as
ensure that the hot wire to the coil is well away from the trigger wires etc.
Also the curve is very odd.
Any tuned engine will like 28* advance in the mid under the pipe, then where the bmep starts to rise as the pipe works, around 8000 in your engine, you start pulling out timing, heading for around 15* at peak torque.
Depending upon how its set up, then less advance may be needed at peak power and beyond to make it rev out.
Below is a curve for similar rpm as your example.


Yeah, as a nightmare. Just think of any error you can come up with: Kreidler had it. Both disks were axially fixed on the crankshaft; they could not nestle against their covers and it took hours to press (!) them into a position that would not yield too much leakage or too much friction.
And take a look at the inlet tracts between carbs and disks. Nice tight U-turn, wouldn't you say? No, for my cylinder I thought up something completely different:
the 24/7-system. I've got no time to elaborate now, but you may find some more info here: http://www.pit-lane.biz/t117p376-gp125-caracteristiques-aprilia-rsa .
The devil is old, Greg. Below left is a drawing I did when working on a Rotax cylinder in 1980, and next to it the 1980 cylinder itself and a recent Aprilia cylinder.
You are quite right: not that much difference in over 30 years.

The ring peg is right opposite the exhaust: the only decent place for it. Each time the ring passes over the exhaust port, it bulges out a little and then gets shoved back in its groove when it runs over the top and bottom port edges. If the ring peg is not diametrically opposite the exhaust port, this shoving back will cause the ring to rotate in its groove and every time it will hit the peg from the same side until the peg works loose....
Don't worry about the ring gap running over the C-port. The Aprilia's C-port is now 15 mm wide, but it has been as wide as 22 mm and even then there were never any ring problems.
Generally speaking you can say that the ring gap is safe over a C-port width of up to 40% of the bore. For steel rings that is; I never tried it with cast iron.......


The yellow trace is the pressure at the exhaust port.

Wob am I reading this right?



On the left the pipe is sucking the cylinder down to late for the transfer port opening TPO.

And on the right the exhaust pulse is arriving back to early, before the transfer port has properly closed TPC.

Page 360


If the stator has trouble supplying enough power, quickly enough,you can increase the "turns before firing" to say 5 or 10.
This gives the system a chance to ramp up, before the ECU starts to fire sparks.

Re your sim printout TeeZee.
Lots to be seen there.
Starting at the top, you are about 500 rpm below peak power in the sim at 11500.
The whole engine isnt very efficient as the D.Ratio is low for the rpm being close to peak.
The TexAv is very high ,over 600
The TuMax is low.
With the depression in the cylinder starting early, then dropping away, the pipe shape is wrong for that rpm.
The pipe is too short for that rpm, as the return pulse has dropped away before the piston is close to closing.
The port timing and the pipe length are not working together, you have no superposition on the far left.
Look at this 40 odd crank Hp RGV100 just over peak, read all the numbers,and note the pressure wave shape, this is as good as it gets.

Edit - you can see the effects of low blowdown, if you get a big jump in Transfer pressure ratio when they open.


yes DR is delivery ratio.
TexAv = average temp in middle of the pipe.
TuMax = max temp of unburnt gas in the squish.
PexPort = pressure ratio at the exhaust port.

Go into help from the Post 2T screen,then plot options, then performance traces, also go to thermo traces for those terms.


Dont get hung up on Bl - STA, thinking its good to get rid of the transfer blip..
Any well developed race engine is ultimately Blowdown restricted, and you will always see the Tr Port pressure ratio rise when they open.
That effect is what makes port stagger work.
The first port to open, initially has backflow, it must, as there is more pressure above than below.
Then the rest of the ports open and eventually begin to flow into the cylinder due to the depression created by the pipe diffuser.
Thus the port that opens first, flows last.
Counter intuitive, but reality, proven on motored, instrumented engines in the lab and reported in a raft of SAE papers - and now shown in the sim.
Getting a balance between the blowdown needed to achieve the power you want, and the transfer area available is the tuning trick most valuable.

Superposition at ExPort opening is loosely referred to as pipe/port resonance, and is best achieved over the widest range with low Ex durations down at 192*.
Unfortunately this is countered by needing alot more blowdown than these numbers allow, and around 198 is needed to achieve the best bmep numbers.
In this scenario we try to achieve resonance at peak and beyond, to give plenty of overev power.

Next issue that is my favorite hobby horse for today is Ex duct exit area.
You will find a heap of free power, when using a T port or a Tripple port configuration, by limiting the duct exit area to around 75% of the Total Ex Port Effective.
Then make the header start at the area = to the Total Effective.
Join these with an oval to round adapter in the spigot or flange, where the width = the header dia all the way thru, to enhance the flow from the blowdown area,and
the height at the flange face forms an oval to give the correct 75% area.

The Temp Av in the pipe should be around 500 as in any fast engine you would measure around 600 in the header.
The TuMax should be around 1000,any more and you get deto, alot less and it means the temp/pressure rise in the chamber isnt high enough, and you are restricting the "push" on the piston.
But can also mean that you are using retarded timing to get heat into the pipe, not create pressure on the piston.

Lots more stuff, so little time.


As an addition to what Wobbly said about the exhaust duct-flange diameter, there is this quote from pitlane.biz:

Quote Originally Posted by Jan Thiel

One wants the pressure wave coming back into the cylinder but NOT the burned gases that are hot and can cause detonation!

and the photos of RSA's duct/flange




Page 364


Wow that RSA has some different bits attached? Frits is that a temp sensor in the exhaust header flange and if so was it connected to the engine management or just the data acquisition system?


Yes, it was a kappa-type thermocouple and it was just for data acquisition.
In fact its position is much too close to the cylinder; there should be room for at least one cylinder volume of 125 cc in the header between cylinder and sensor to avoid fresh charge hitting the sensor. But mounting the sensor further down the pipe proved impractical because there it was quickly destroyed by vibrations.


Firstly you are misguided re the reed trace - this represents reed tip lift, there is no "pressure ratio" being shown.
The reeds will flat line at the max lift if you use a stop plate.
The length of about 135 for a 12,000 rpm engine has an effect over a much wider range, than the longer intakes, as the pulse frequency is greater, and the crossing point doesnt
move as much with a change in rpm.
That length is what was achieved in the dyno graph I posted back a bit for the TM125MX - just taking 15mm off the rubber gave 2 Hp in 50, and worked over a wide range.
It used a SPJ short carb from a HRC RS125, and a very short rubber off a earlyer model with the same bolt pattern.

Re the Ex duct nozzle.
The area at the cylinder duct exit should be around 75% of total Ex effective, simply change this in the Ex Port page.
Then you should have at least 30mm or so of "flange" to increase the dia up to the header size ( this would be an oval to round CNC transition).
Your small taper is way too steep, and kills energy in both directions.
This flange is part of the pipe, as you have done.
When done right this is the result - no nozzle = a 45mm duct exit straight into the header.
The curves above had a 39mm dia duct exit, with a 30mm long flange going up to 45 dia at the header.


Sorry if this is a stupid question... but do you want to have a step at the top and bottom where the flange/duct meet?? I imagined the CNC oval/round transition to be smooth but it looks like its not the case in the RSA photos above???

This seems like a key bit of tuning advice so i want to be 110% sure i get it. Ive mostly worked with MX motors and most have this 'step' top or bottom or both


Thats what ive been wondering... taking the quote earlier from Jan Thiel into account (about wanting the return pressure wave but not the returning gasses) I would guess that the step hinders the reverse flow of the burnt gasses , possibly by bouncing back a small wave back down the pipe as the reverse wave returns to the exhaust duct??

*** on second thoughts the 75% oval to 100% round transition will create a reverse wave just fine by itself (even without the step) as the initial wave returns though it.


A stepped transition at the header joint is common on fourstrokes for just the reason Jan Thiel stated.

If I remember correctly it will flow just like a cone section for outward gases. The step has no effect on the return wave activity but does resist returning "solid material".


The areas of a header transition is whats important - a 39 duct exit is 75% AREA of a 45 header,39 isnt 75% of 45 obviously.
The 75% isnt set in stone - just a guide.
I have noticed that the best ratio seems to be when you use the header area the same as the full Total Effective Area of the Ex Port, along with a duct exit restriction
nozzle about the area of the main port.

Re the smooth transition nozzle Vs a stepped design.I started to experiment with this after getting hold of a genuine A Kit Honda spigot.
I did a series of dyno tests using a late model HRC RS125, when beta testing Luytens cylinders.
The cylinder as first produced had a 40 by 35 duct exit oval.And as a reference any dummy that removes the oval and makes it simply 40 dia round, just lost 2 Hp and all the overev power.
This was first tested with a simple 40 dia round spigot, thus having a step - top and bottom.
Next I bolted on an early model A kit RS250 spigot, this is a cast oval to round transition from the factory.This test immediately gained around 1.2 Hp, and alot more power past peak.
Then I ground the duct out to 41, and welded the duct up inside as far as I could, to enable a 32 high oval shape.
Hondas later model RS250 A Kit has this size spigot but with the oval 35 high, so I welded that and reshaped it as well to 32 high.
A new pipe with the bigger header was built to suit.
This gained another 1.5 Hp, so as a last test I made a simple 41 round spigot - and this lost all the power just gained.
The 41 by 32 oval was right on 76%.

So - I can say definitively with a T port that the transition is better than a step, but all the 3 port engines I have done have made alot more power as well, though not as well tested back to back ( I was paid to do the T port testing ).

I believe that the Aprilias slightly different system can work just as well, maybe even slightly better - as im sure Jan Thiel would have tested it to death, as it promotes the flow from the triple ports right up to the header.
But when you are modifying an existing design, the CNC oval to round setup is quite easy to implement, on a T port or a triple port design, especially as I have tested it to death on 50cc up to 500cc cylinders,and given you the basic numbers to follow.

Edit - re the so called "power port" idea.This was developed as a tuning aid back when engines made no power at all, and running a bigger piston port timing, along with forcing inflow to be pushed thru the boost port, just happened to add a Hp or 2 on top of none to start with.
What we find now is that cylinder reed engines always end up being power limited by the effective STA that can be obtained by cutting holes in pistons, adding big Boyesen ports and even then adding floor ports.
All this is attempting to get the inflow around and or thru the piston that is in the way alot of the time.
That is why case reed is ultimately better when done properly.


Just a couple of things to note - the program will crash with an entry greater than 100 for duration - its not a "real" entry.
And your ignition timings are very wierd - never ever seen any 2T that will run 40* at any rpm.
But for example running straight Methanol in a 125, the dyno testing has been done a hundred times, and won dozens of titles.
Run 18.5:1 com ( 17.5 in air cooled ) and a "normal" ignition curve for petrol, ie around 28* in the mid and 15* at peak torque.This sort of setup gives the best power every time.
Its a long drawn out fallacy that you can make big power by taking a petrol based engine, pour in a high latent fuel, and simply wind in timing - it doesn't work.
Its best to run an "average" input for the variables until you are confident with the other inputs, then run turbulent,then transfer the calculated data.
These are 12 for AFR, 9 for delay,50 for Duration,6 for VibA, 1.25 for VibM.
This always works well as a baseline.


From what I've seen you can gain 20 HP right there if you can convince Rossi to shield his pipes from the boat's rooster tale. Talk about water-cooled exhausts....


Im sure you are right Frits, I saw the water spraying all over them in a video.
Then they tell me they only have 420* in the header.
They run absolutely mental compression ratios, then drown the engine with fuel, and use extra big stingers to stop it blowing up.
Even on jungle juice they make way less power than you guys were on unleaded, the pipe design is a joke.
Much to do.


The extra mid range power was all down to using ATAC chambers on the top two cylinders, as well as the original PV blades.

Page 370


The calculator in EngMod was added by Neels after I had done dozens of tests with tripple and T port designs.
The calculator simply uses 75% of the total effective port area as a guide.
This always works and always makes alot more power and generally I found that the duct exit should be about the area of the main port alone.
This usually ends up around 75% of the total ( by taking away the extra area of tripple ports) needed for lots of blowdown - thus power.
It was never intended to be used with a single port only as I havnt tested that at all, apart from years ago on TD3s etc, and we always went bigger back then, not smaller.
Theory says that having a smaller duct volume changes the Helmholtz frequency ( higher ) , and reduces the amount of exhaust residuals able to be stored in that duct ( meaning more clean mixture sits close) , but im not sure this theory will apply to making more power with a single port.
Having said that, a 40mm pipe entry on an engine only making 30 Hp is way too big, so reducing the duct and or header area, or maybe both, will very likely work real well.
Did you model the nozzle as a short tapered section ( 30mm say) from the duct exit up to the header dia ( as the first section of the pipe) and this is made as an oval to round transition in the flange on T port and tripple port designs.
Be real interesting to see if the sim reflects reality on a dyno, in your single port scenario TeeZee.

373


EngMod2T

I have been looking at exhaust port nozzels, now I would have thought the best arrangement was to have the exhaust port gently opening up starting at the port window and flaring out to the expansion chambers header diameter which is 40mm on my bike(old RS125 chamber).

But EngMod2T and Wobbly tell me that a nozzel shape is what I need for top end and over rev.



First step was to model the exhaust port then click on calc to find the predicted best nozzel diameter.



You can see that it is less than the effective diameter of the port exhaust port window itself.

I tried nozzel diameters from the diameter of the expansion chamber header at 40mm, 38-36 and 34mm. All other aspects of the model were the same, just the nozzel was changed.



A 34.5mm nozzel (green line) worked the best as the nozzel diameter increased top end and over rev dropped off.

The exhaust port outlet (nozzel) on my bike is currently 40mm, I guess I will be trying a 34.6mm one soon.


The calculator in EngMod was added by Neels after I had done dozens of tests with tripple and T port designs.
The calculator simply uses 75% of the total effective port area as a guide.
This always works and always makes alot more power and generally I found that the duct exit should be about the area of the main port alone.
This usually ends up around 75% of the total ( by taking away the extra area of tripple ports) needed for lots of blowdown - thus power.
It was never intended to be used with a single port only as I havnt tested that at all, apart from years ago on TD3s etc, and we always went bigger back then, not smaller.
Theory says that having a smaller duct volume changes the Helmholtz frequency ( higher ) , and reduces the amount of exhaust residuals able to be stored in that duct ( meaning more clean mixture sits close) , but im not sure this theory will apply to making more power with a single port.
Having said that, a 40mm pipe entry on an engine only making 30 Hp is way too big, so reducing the duct and or header area, or maybe both, will very likely work real well.
Did you model the nozzle as a short tapered section ( 30mm say) from the duct exit up to the header dia ( as the first section of the pipe) and this is made as an oval to round transition in the flange on T port and tripple port designs.
Be real interesting to see if the sim reflects reality on a dyno, in your single port scenario TeeZee.


Pinched that bit from the later RS example file that came with the simulator, I expect its a tail pipe venturie that controls the bleed down and that the rest of the tail pipe does not come into the equation.


The exhaust exit "nozzle" was used first by Helmut Fath ( my hero ) when tuning for Honda where their V twin 250 had one stinger 150 long the other 450 long.
I have tested all manner of variations and the best is around 10mm of parallel nozzle and then 10mm of divergence to a stinger around 1.5mm bigger.
This reduces the effect of the waves bouncing up and down the stinger off atmosphere disrupting the rear cone waves.

The pipe vol/engine cc field in the pipe screen was added by Neels to the program when Frits noted that he had calculated this for the RSA - maybe he can elaborate on the relationship.
Note also that there is two fields for the length to end of header and length to end of diffuser.
I got Neels to add this as so few pipe designs are "correct" and its a pain to calculate all the time.The header end should be 30 to 32% and the diffuser should be 64 to 68%

TeeZee - really glad that you are looking at the STA numbers and realising that the sim is telling you what is needed - or not in many cases.
Getting all the elements of a design in harmony is what makes big power numbers.
I would try making the divergent header nozzle longer - very short ones can create shock waves and reduce the energy available to do positive "work" in the pipe.


There is a relationship between how wide you make a port, and how gradually it should widen in order to keep the ring healthy.
With a good ring, 70% chordal of the bore is the optimum width. If you make it any wider, the widening has to be so gradual that you loose surface area at the top, where it counts most, because that's the area that opens first and stays open the longest.
The drawing below shows that with too wide a port you have to sacrifice the yellow areas at the top. But sacrificing those areas costs blowdown angle.area. That red port may have more open area, but not where it counts, at the top; the blue port is better.


Unless you keep the revs really low, a single exhaust port with a 70% chordal width does not give sufficient blowdown time.area, but because of the reason I explained above, making the port wider will be even worse. You will either have to use a bridge, add auxiliary exhaust ports, or raise the timing of the single port to well above the 190° that is optimal for pipe resonance.

The Aprilia cylinder is extreme in that respect: the middle exhaust port is 38 mm wide (older versions were 40 mm wide) and there are huge auxiliaries but even so the middle port is raised to 196° and then it gets a large radius at the top. The radius makes it difficult to measure the timing but if you shove a piston ring in the bore until you can just see light between the ring and the bore, you will find an exhaust timing of 202°. Don't try this at home, unless you want your engine to produce its maximum power at a mean piston speed of 23.6 m/s. But then your transfer time.area will probably be insufficient. And you know: if you raise the transfers, that will eat into the blowdown time.area.

Why does Aprilia use an exhaust timing that is too high for optimum resonance? It is a compromise: any lower, and the maximum torque will rise, but the reduced blowdown time.area will cause an early torque collapse and the product of torque times revs (yes, that's power) will be lower.


The Rotax 24/33 rear cone was dropped in Superkart racing when I discovered that a single 28* made more power on the dyno.
This led to the development of the so called Silverstone pipes that we made when I worked for JL when he was still in England.
These won dozens of World and Euro titles.
I have spent days of dyno time testing multi angle rear cones, and have always been able to achieve the same or better power with a single rear of the right angle.
In many cases the sim likes a sharp rear cone, but in reality its no better.
Seems to me that the main reasons you got better power with the modified pipe, was down to a gradual front nozzle, stinger nozzle, and a way shorter tuned length.


STA stands for Specific Time.Area. STA depends on rpm: the higher the revs, the shorter the ports are open per revolution. So I can only give you STA numbers if you specify for what rpm you wish to know them.
It's like this: a cylinder has port windows with a certain width and certain distances from the cylinder top plane to port roof and port floor. You can only express the window dimensions in millimeters and square millimeters (or in other funny length and area units that english-speaking folk still use).
Put this cylinder on an engine with a crankshaft with a certain stroke and a certain conrod length. Now you can also express the window dimensions in crankshaft degrees.

Now we can look at the angle.area concept (the point between angle and area indicates a multiplication; I make a point of writing it like this )
Let us assume a port window is 1 mm wide. Turn the crankshaft until the window is on the verge of opening. Its open area is still zero.
Then turn the crankshaft 1° further. Let's say the piston descends 0.5 mm, so the open window area is 0.5 mm height * 1 mm width = 0.5 mm² , and it has been open for 1°; that yields an angle.area of 1° times 0.5 mm² = 0.5 °mm².
Then turn the crankshaft 1° further again. That first 0.5 mm² open area has now been open during 2°; and as the piston has descended some more, there is now some additional open window area that has been open for 1°. Multiply all those pieces of open window area with the number of crankshaft degrees they have been open, all the way from initial port opening till port closing, and you get the total angle.area of the port.
But for gas flow it does not matter during how many crank degrees an area has been open; what matters is the number of seconds it has been open. That is where engine rpm comes into play: twice the revs means half the time; angle.area divided by rpm is time.area. And if you divide time.area by the cubic capacity of the cylinder that has to be filled (or emptied), you have specific time.area.
You may have noticed that in previous posts I sometimes talked about angle.area, and sometimes about time.area. And hopefully now you understand why. When I talk about an engine, I use angle.area. When I talk about a running engine, I use time.area.
O, TZ350, before I forget: here is what you have been asking for:


In the pic you posted, would that blue port make engine peakier, because of the sharper exhaust pulse?


In theory, maybe. But there are other, stronger effects. The sides of the wide red exhaust port are much closer to the A-transfers than is the case with the narrower blue port. That would provoke short-circuiting


EngMod2T



I was trying to explore the effect of various nozzels at the exhaust port, thay are all 34mm and vary in the exit angle and length.

They started at 5mm long out to 30 mm and the angles varied from 61-33-22 degree to 11 for the 30mm one.

Now I am not sure if the change in overall tuned length was making the difference or the angle of the nozzel but food for thought.


Hey TeeZee, I think what you are seeing is related to the fact that the sim cannot replicate the flow regime that an oval to round transition creates in the spigot.
The wide oval shape, that keeps this width right thru to the header start,really promotes the flow from the top of a T or the tripples in that setup.
But as I said at the start of your experiments I have not tested the relationships or area changes in a single port engine.
My feeling is that just maybe a single port would "like"a small volume duct,and then a step at the header - as your short transitions seem to help top end, at the expense of some area under the curve leading up to peak though.
I have asked Neels about the ideal way to model this as part of replicating a sliding header project I am working on ( as this has a step at the end of the header).
You cant have a "zero length" step within the pipe, so I have asked him what to do.
Will let you know the result.


Thanks, Mental; everything seems to be fine now. So here they are again:

http://www.kiwibiker.co.nz/manual/Aprilia-1.zip (6.8 MB)
http://www.kiwibiker.co.nz/manual/Aprilia-2.zip (8.3 MB)
http://www.kiwibiker.co.nz/manual/Aprilia-3.zip (9.2 MB)
http://www.kiwibiker.co.nz/manual/Aprilia-4.zip (7.2 MB)
http://www.kiwibiker.co.nz/manual/Aprilia-5.zip (5.6 MB)


Why put the plug inside the pin with a "new"" groove,there is already a groove available and also there is a chamfer on the end of the pin that can be used - as it was previously - to force outward, the retainer
into this groove.
Wont say any more as this stuff is Frits intellectual property , but with all the pics flying about its quickly becoming public property.
I made these plastic plugs several years ago using glass reinforced Peek,and tested them with no positive results at all.
But now we have tripple ports reaching around to 1/2 bore, and yes they do work a treat.


Re TuBMax, this is the temp of the unburnt end gases in the squish.
It is affected only by a few factors.The main ones being ignition advance and effective compression.
Effective com is composed of the static com as set by the cc in the head.Then you add dynamic com to this.
The dynamic com increases with charging efficiency ie more air/fuel in the cylinder per stroke - better trapping efficiency ie more air fuel kept in the cylinder per stroke, and lastly scavenging efficiency - less exhaust residuals left behind per stroke.

As you increase the last three mentioned, then the effective compression within the cylinder, as the piston approaches TDC, becomes greater, and more fuel is burnt - creating more pressure and heat, thus power.
Then you will reach a stage where the end gasses detonate, due to radicals forming,from excess heat and or uncontrolled pressure rise.
The only way to reduce this , is to drop the static com or reduce the ignition lead.
As you approach the theoretical limits of charging,trapping and scavenging efficiency,then you have to balance this with a static com and or ignition advance that will keep the piston alive.
This is exactly what happens on the dyno during development - its a juggling act to balance the com and advance to get the highest cylinder pressure you can, to release as much heat into the gas as is possible ,at the right time to suit the engine characteristics needed.
Com and advance put more of the finite fuel "energy" into the piston and cylinder and then eventually into the water - thus this energy is lost, and cannot be used in the external sense ie to heat up the pipe and generate
more overev .
But pushing the limits of all the factors ,in some form of synergy, is the black art we are only just beginning to be able to reliably juggle with in a good sim - without locking up a piston and a rod coming at you thru the screen.

Hope I never see that error on my screen - looks bad.

End of page 380


As I said in the previous post we need to address two important factors in a 2T engine design.
Torque and rpm
It all comes down to Hp = Tq*RPM/5252.
Keep the torque constant and increase rpm by 10% and you get 10% more power.
Hard part is holding up the torque at the higher rpm level.
A short stroke will allow greater safe rpm, but the bore area needed to create the angle area needed, is limited more and more as you increase the piston size at the expense of stroke length.
The piston gets heavier as well, so ultimately the engine may not physically be able to rev to anything like what the stroke may allow.
Yamaha tried for years to fight Honda with a 56 bore size.The 250s failed miserably from Haradas win in 93 all the way up to 2000 when Jaques won easily on the new square engine derived from the 500.
The 125s won in 74 then never again.The short stroke 500s were useless except for the Rainey years, where he rode the wheels off the thing and Kennys bench was real deep.
The bottom line to all this is that the square engine has the best compromises of rpm capability Vs useful bore area.
Go short stroke and though you may be able to rev it, the scavenging is compromised by the bore availability.
With long stroke - the reverse happens.
This all assumes we are talking max power capability - 250cc MX is all longer stroke now as this favours torque production from low rpms,and the extra rpm capability of a square engine isnt needed to create peak power numbers.


Wob, just looking at the hand drawn pipe in this list Frits posted (pijp 21) & looking at the stinger venturi; -it would tend to follow your rule of parallel section diffused out ~1.5mm larger, - the only thing I am confused about is the smallest diameter is ~23mm which is what I’d expect a conventional 125 stinger to be.

I thought the idea was to run a very short section at a smaller di than you’d run a conventional stinger mimicking the restriction of a longer pipe? So even though the drawing is exaggerated the diameter isn’t that small. I was expecting 21mm or something like that. Is it because the last baffle stage is steep? Or the requirement to get heat into the pipe can be produced by other means of ign & powerjet so stinger sizes have increased? It still seems odd. Or am I just wrong about the smaller than conventional size part?


The stinger config in pipe 21 is exactly what is needed for a 125 making anything like 50 Hp.
I have been using CNC nozzles I had made over 10 years ago that are 23.2 at the smallest section specifically for the pipes I have built for karts that make around 50.
For a 125 down at 40 Hp then 22 is about right, as is used by the CR125 engines in SKUSA stock class,down at 30 Hp I would say 20 or 21 ( never built one, sorry)
It all comes down to the amount of air that is dumped into the pipe, and this is totally reflected in the Hp numbers - empirically these sizes work every time to generate the correct back pressure, without causing deto or finicky tuning issues..


Which is why my pipe has a removeable end piece sandwiched between the end of the cone and the tailpipe. It is just a little piece of cone with a precise diameter nozzle. I tried one size then went up one and made more power on the dyno. Funny enough it felt better initially on the track with the smaller one.


Like below? Red is the exchangeable restrictor. Blue is its container, welded to the yellow endcone at the left. The yellow pipe at the right is the tailpipe (held in place by a spring) with a bigger diameter than the restrictor.


Not as fancy. Mine has no venturi and is made from .8mm sheet. The two sizes I have were formed very tightly around the required size rod, welded, and then hammered with a rubber mallet. The end result is a perfect fit with a nice smooth finish. I might look at doing one with the venturi.


Make your own from say .8mm sheet. If you cut it nice and straight on a guillotine it comes out very nice. I have a good selection of different size axles which I form it on. Once welded it typically jams on the axle but a bit of smashing it with a rubber mallet soon frees it up and leaves it looking good. I form a lot of stuff from .8mm sheet - exhaust mounting brackets, brake stay arms, engine mounts. I have a couple of lumps of steel for beating it over and getting it flat so it welds up nicely.


Kawasaki have had subs above the mains for along time - they have a PV in the subs , not the main port.
I did a 125 for karts a long time ago that won a National Title, but I dont think that the idea is specially better or trickshit.


NGK race plugs were originally designed to be about 1mm proud of the chamber,one reason there are no threads on the shell end.
This leads on to one reason that a toroidal chamber design works best.
I believe that plug position and indexing effects are reduced considerably by the quality of the CDI and the energy in the gap.
Using Ignitech and 0.2 Ohm primary Aprilia RS250 ( RGV) coils, I tested plug indexing and found no difference - but the fine wire R7376-10 plug made near on 2 Hp in 50 against a
Denso RS125 plug and a B10EGV.

TeeZee, use the new pack and go feature and send me your files - I will get bored over Xmas at the motherinlaws, and have a play on the laptop.


End of page 390



So far I have got to page 390 on this thread and accumulated 29 pages of posts relating to pipes.

[wobbly]

Yea sadly, I have said this before as well.
NoMates engine was designed well over 6 years ago to make 32 crank Hp, first run on Brets Dynojet it made 27.6 RWHp - thus fucking perfection, at the time, as far as I was concerned.
Then it went on to run superbly for 3 years, winning 3 bucket titles in the process, with no issues whatsoever.
The rider, doing no maintenance at all due to work pressures, then proceeded for another 3 years to detune and fuck with it, causing all manner of reliability issues in the process.
Its now been redone properly, with Ignitech, chrome bore etc.
The dyno , a newer 168 with full load control,now says it has a huge increase in mid power due to the servo PV , and it makes exactly the same power it did before, on a simple rolling road,as per ESEs test unit.
Meaning ,in reality, its way ahead of the previous baseline.
So, as the old piece of shit that still holds the lap record at Mt Welly is now a quantum leap better than before,bring on the CVT ideas.
You will need alot better than that trick shit technology,to beat NoMates in a head to head.
Really fast engine, maniac do or die rider.
But what do I know.
Jack shit, obviously.

[husaberg]

OK technical question Mike has about 30 hp from around 100cc so that's about 300 HP/Litre
Rob has about 30 HP from around 125cc so that's about 240HP/Litre

Rob is of course constrained by the air cooling rule Mike is not.(although i think he is currently only liquid cooling the head)

Rob is constrained by the 24mm carb rule. Mike unconstrained by any carb size rule and has i assume a 36mm carb

Does that mean. Often a larger carb than is actually necessary is used for the race engines?
Or is the additional 25cc of Rob's engine is drawing more airflow threw the carb to make up the difference.
Or does the more constricted airflow through the Reed valve nullify most of the gains compared to the less restrictive rotary valve.
Therefor the reed engine needs a larger carb?

Putting aside Robs clever use of the venturi a 24mm carb only has an area equivalent to 1/2 that of a 34mm carb............
Although i guess Mikes revs higher and Robs engine is bigger which may account for the difference.....

hoping someone will be able to answer.........

PS that 24mm carb rule seems to have be about exactly right............

[wax]

Is the carb open on the 100cc engines ??

[husaberg]

Is the carb open on the 100cc engines ??

Yes
Most of the newer builds are 36mm Keihins shorties with TPS and Solenoid PJ. 99ish kx125 and i guess others makes used them as well

or RGV downdrafts.

[Frits Overmars]

All I need to know is what to get that is legal for my class of racing, and where to go to get it. Speedpro suggests something Yamaha from Malaysia as he tells me there are plenty of tuning parts for road scooters and bikes that don't have the illegal words "Racing" or "For Competition use Only" printed on the packaging.Don't forget to look beyond two-wheelers. There's a world of CVT goodies for snowmobiles.
I almost forgot: Wob, with a CVT you can omit the power jet. And the quickshifter. And the trombone pipe. And a load of sprockets. And the power valve :devil2:.
(And even the variable ignition if you can get the CVT to keep the revs from dropping when the throttle is closed).

Teasing apart, it is my considered opinion that shiftboxes would have disappeared decades ago if the FIM hadn't blocked their development.

In the Beginning... No, there were no two-strokes in paradise (which makes me wonder why they called it paradise).
OK, some time after the Beginning riders had to manually adjust mixture strength. They had to manually adjust ignition advance (and re-adjust their contact breaker points every saturday).
They also had to fiddle about with hand- and foot-levers to constantly adjust the transmission ratio between a more or less fixed crankshaft speed and a variable riding speed. This fiddling was called gear shifting and the need for it lasted until well into the 21th century...

[SS90]

Don't forget to look beyond two-wheelers. There's a world of CVT goodies for snowmobiles.

OK, some time after the Beginning riders had to manually adjust mixture strength. They had to manually adjust ignition advance (and re-adjust their contact breaker points every saturday).
They also had to fiddle about with hand- and foot-levers to constantly adjust the transmission ratio between a more or less fixed crankshaft speed and a variable riding speed. This fiddling was called gear shifting and the need for it lasted until well into the 21th century...

I have several knowledgeable people make similar arguments Frits, but I have never seen this in action (snow mobiles seem to be the business that's for sure)

Is is practical and realistic to expect a CVT to be suitable for riders of all weights, I only see skinny buggers making use of the advantages, whereas geared bikes can quite often be competitive ( in the right hands) with a "portly" rider, it seems that from what I see, CVts are only suitable for ideal rider/bike combinations

[wax]

A cvt engine does not care about the weight on it. the power to weight will be down much like a geared bike. The cvt engine will still happily spin at the rpm you set it to. The only way it would change is if the cvt was incorrectly set and then the engine could load down as it was going up through the gearbox to fast. A lighter rider will not show up a poorly set up cvt as much as the load on it wil be less but the bike will still be slower than a lighter rider on a correctly setup cvt.

If you set up a cvt incorrectly so its reving below or after its power peak then yes a geared bike will be faster. But then if you run a gear higher than you should on a geared bike you will be slower as well. It comes down to setting it up correctly

[Frits Overmars]

Is is practical and realistic to expect a CVT to be suitable for riders of all weights, I only see skinny buggers making use of the advantages, whereas geared bikes can quite often be competitive ( in the right hands) with a "portly" rider, it seems that from what I see, CVts are only suitable for ideal rider/bike combinationsIt may not be easy for you to swallow, but Wax is absolutely right.
If you see 'portly' riders beat skinny buggers, then there is something else playing a role as well. They have more power and/or better roadholding and/or they are simply better riders. All these things being equal, the heavy bloke doesn't stand a chance, gearbox or no gearbox.

[Brian d marge]

I would assume that acuallly fairly close to how the Japanese actually manufacture the frames after the intitial frame is built.
maybe sir Stephen (our Japanese based corespondent) can confirm this

the frames are not exactly cutting edge I m sorry , Aluminium frame have extruded sides then the are place ( I think ) one side at a time in a Jig before being welded to the head stock
MotoGp frames are hand made in a strict welding order to avoid distortion

tiss all I know

Stephen

[bucketracer]

Recently I tried a 30mm carb to see if it would make any more power than my 24, it didn't ...

273974

30mm carbs curve (Blue line) ... the 24mm carb (Red line)


Rob is constrained by the 24mm carb rule. Putting aside Robs clever use of the venturi a 24mm carb only has an area equivalent to 1/2 that of a 34mm carb............

I know it doesn't answer your question, but when TeeZee tested his 24 against a 30 in a back to back test. The 30 didn't make anymore power than the 24 and so he thought that meant the 24 could do better yet as it must be something else holding the engine back.

[husaberg]

I know it doesn't answer your question, but when TeeZee tested his 24 against a 30 in a back to back test. The 30 didn't make anymore power than the 24 and so he thought that meant the 24 could do better yet as it must be something else holding the engine back.

Yeah i was surprised..... but then thought, well everything else on the engine was optimised for the 24mm carb anyway. I then assumed it was not really persevered with either. So how many runs and combination were actually tried?

I also guess it exceeded the max number of answerable questions.

But going back through some stuff it looks like some data Frits posted suggests the Rotary valve is worth about 4 HP over a similarly well developed crankcase reed with similar spec.(with a 125cc cylinder.)

So that could theoretically push an engine of TZ's spec down to 26ish HP (about 208 hp /litre) if it was a Reed instead Rotary valve (in outright HP anyway)
The same basic (possibly wrong) math would of course suggest that the 100cc reed valve engine might expect to gain about 3.2 hp to end up with 33.2 (or 332HP/litre)
if it was a rotary valve...........