ESE's works engine tuner

[husaberg]

Yes me thinks so 2, +1 +1

Post number 5000 (your one) Con grads Team ESE maybe you should bring in Thomas for another photo shoot.


Talking ESE's works engine tuner
This is Thomas a Vietnamese race mechanic, you know that place where they have all those hot 50's and 125's are big bikes.
Thomas, ESE's Race Team's Tuner is fettling number 9. adjusting the port timing for Taupo.
Its hard to see but he has taped a degree wheel to the magneto flywheel so he can mark out the exhaust port height he wants.
None of this raise the port 3.5mm for a gazillion HP nonsense. He knows what timing he needs and sets the crank position there before marking the port and then doing the hells death port job that we all dream of.
You should see him setting up a carb. Talk about pain staking, he starts with a main jet so big the bike floods at about half throttle (apparently this proves the oriface of the needle/needle jet combo is big enough) and then he slowly step by step works back until it runs clean.
Most people start at the bottom with a carb and work up, He starts at the top and works backwards.
Never seen him blow one up. But then he is intelligent with the throttle and does not ring its neck when the engine is in distress.

Boy o Boy am I Looking forward to Taupo.

Will Daves 100 be finished in time?

Last attachment contains past the main jet 3 times I believe this was raised earlier.

I was looking for the book I was talking about an came across this Blair. Has anyone read these I always wondered about the SAE papers. I guess this is where they are.
http://books.sae.org/book-r-161
Here Is a list of two stroke tuning books the one I was thinking about is Draper The sister book to your one is exhaust and?
http://www.2strokeworld.com/forum/index.php?topic=2022.0

[F5 Dave]

I told you, it is finished. . . Its just not really finished in a sense that it runs but needs some serious development. and a modicum of money:shutup: a large amount would be better, but the small amount is the current stumbling bock.

[TZ350]

Got a complete clutch assembly from Kickaha today, its a six plate unit with the normal spring setup, just what I wanted, looks like it can be made to fit and with a bit of work maybe a seventh plate can be squeesed in too.

[TZ350]

247485247486247487

Had a great evening with Buckets4me running up the pumper carb and divider inlet tract on the dyno.

We are now within 1 hp of our previous best useable power (28.9 rwhp) that we got with the side carb. The pumper with the kart air box gave the best results.

The laptop was still not talking to the Ignitec so I expect more improvements when I can adjust the ignition curve. And I still haven't come to terms with adjusting the pumper carb either so there might be a bit more in that too.

We got all sorts of graphs, when the carb was rich and fat down low there was quite a big torque increase at the beginning of the curve but it would go bananas up top.

I can get it to run low and pull then run clean and make power at the top but the transition is still a problem. It might be that I have to play with the pop off pressure.

Currently it pops off at 8psi but leaks back to 6, I am not sure if thats OK or not ....

Of course, in my efforts to get the carb up and out of the way I have made taking the top off hard, so its not that easy to get at the diaphragm and needle spring without taking the carb right off.

Still I am pretty happy with the way things are going, hopefully Buckets4me will post some of the pictures he took.

[Buckets4Me]

First Picture, Red line is the best useable curve managed so far, Blue line is the 24mm pumper carb. Now the laptop is working again TeeZee figures that with some more carb and ignition tweeking he might get 28+.

Second Picture, Red line is the original inlet manifold, Blue line is the same manifold with the divider fitted.

[husaberg]

I told you, it is finished. . . Its just not really finished in a sense that it runs but needs some serious development. and a modicum of money:shutup: a large amount would be better, but the small amount is the current stumbling bock.

I hope you don't mind Dave but I was talking with a guy who sponsors me about your plight.

Now "Bob" said he could identify with you as he sees you as a kindred spirit.
He was so taken with your story asked me to offer this a a starting point (See below).
He also said he had been following the F4 build for a quite a while.
All he asks in return, is that you give him a vote in the next MNZ elections.
He did mention due to some problems with Visas he might not be able to get to Taupo, but wishes you all the best.
The eggs are not included sorry.

[F5 Dave]

No I think the 100 mill is what buys the eggs.


TZ have you done an all-gears run to see the kart carb transitions nicely when thrown a bunch of gear changes?

[bucketracer]

TZ have you done an all-gears run to see the kart carb transitions nicely when thrown a bunch of gear changes?

Watching it on the dyno and it doesn't transition between low-high jets very well so TZ is a bit doubtfull, we probably need to talk with someone who has some experiance with these carbs.

[F5 Dave]

may be a game changer as KT100s are single gear of course, not that I have aqny kart experience aside from seeing them in the pits at Bike/kart meets.

[TZ350]

247542

Hopefully the carb will work on the track OK, but whatever, its pretty impressive how much hp can be sucked through it.

[TZ350]

30 hP Comparison

247544


Green line is where I am now with the Tillotson pumper carb and single exhaust port barrel. Red line is Speedpros 30hP MB100.

Blue line is a cylinder that was modified for extra side exhaust ports. When I tried it a while back the crank needed balancing and the engine vibrated so badly that I lost my nerve and shut off before it had reved out.

Interesting its so close to Speedpros curve, now the crank has been re-balanced and runs smoother at big revs I might have another look at the triple porter with an eye to the Taupo GP.

[TZ350]

Inlet Manifold Dyno Test

247545

Red line is the original inlet manifold, Blue line is the manifold with the divider fitted.


I have put a curved divider in my inlet manifold. The idea is that (1) in a curved inlet like mine there tends to be a traffic jam on the outside wall as the inlet charge tries to turn the corner. Basically the divider (2) makes it into a two lane highway insted of a one lane bottle neck.

[husaberg]

No I think the 100 mill is what buys the eggs.


TZ have you done an all-gears run to see the kart carb transitions nicely when thrown a bunch of gear changes?

You can't have both Dave "Bob" has been getting some bad press lately and is having er...Difficulties accessing funds From Zimbabwe. He also asked me to ask about any farms avail in NZ

The pumper carb my mate ran, was sweet all around on a MB100. It was off a jetski and huge though. Disk valve may be more problematic.

The only problems he encountered with it were as I had discussed with TZ earlier with overrun. He was admittedly a Kart guru type.You would be best as suggested above to find a chainsaw or kart Guy is my two cents worth.
I will take it out of Daves sponsorship money.

Did you get around to modifying the pop off?

BTW what sort of CHT does it run TZ i have never seen any figures for it it must be getting up there now underload. Even with cooper fins and all.

[bucketracer]

BTW what sort of CHT does it run TZ i have never seen any figures for it it must be getting up there now underload. Even with cooper fins and all.

I have been helping TZ with the dyno tonight, the hotest part is the copper fin next to the exhaust, the copper head fin is much cooler, both are easy to touch. I can easily keep my hand on the alloy part of the head near the plug after a heavy dyno session. But then it does cool fast, I will have to get the lazer thermometer out and try to get some readings while its under load.


Did you get around to modifying the pop off?

Tried 9psi then 7 then 12, on 12 I had the low out three turns and the high one and a bit. So I guess 12 is to high. will go back and try 10 next.

Problem is to get it to come back onto the throttle properly, with the pop off at 12 and the low out three turns it would pick up then there would be a mild patch then it would take off again so we guess 12 is to high causing a mild mid lean out.

Its like the pop off is the pivot on a seasaw and High and Low are the ends and adjusting the pop off is like adjusting the overall height of the seasaw.

I will have to do some reaserch on the net about tuning pumpers and see what I can come up with.

[wobbly]

Pumpers are pretty easy to suss.
The pop off pressure simply sets the amount of fuel passed up to 1/2 throttle, transition from closed throttle,and around idle.
This should be set such that the bottom jet is no more than 2 1/2 turns out for the correct fuelling in the bottom end.
The pop pressure should be set with the needle and seat wet, and should hold its set pressure right up to the point of blowoff.
The top jet sets the fuelling past 1/2 throttle and mainly affects the ratio delivered at peak and beyond.
This should be less than a turn.
The pop off lever height sets the overall amount of fuel able to be delivered, the higher the lever the sooner, and further the needle is pushed off the seat, allowing more fuel to pass to the jets in total.

[TZ350]

Pumpers are pretty easy to suss.....

Thanks Wob for the tips........ probably get to look at this again in a few days.

[bucketracer]

TeeZee some pumper carb tuning tips to go with Wobblys info. 247635

And here is something if we really cock it up..... :laugh: ...... piston seizures explained 247636

[koba]

may be a game changer as KT100s are single gear of course, not that I have aqny kart experience aside from seeing AND HEARING them in the pits at Bike/kart meets.

I've amended that post for you Dave...

[koba]

And here is something if we really cock it up..... :laugh: ...... piston seizures explained 247636

Looks a great read...

It's sad when I can instantly scratch together 4 or 5 examples of seized pistons to apply the article to!

[wobbly]

One thing I completely disagree with in the piston seizure write up is that air leaks cause a lean condition.
This is utter bollocks, any engine with a case leak will run richer, the bigger the leak the richer it will run.
Caused by the fact that the case "pump" no longer works and the fuel air mixture isnt being transferred thru the ducts.
If the engine is then leaned up to "fix" the incorrect mixture - then it seizes.

[husaberg]

One thing I completely disagree with in the piston seizure write up is that air leaks cause a lean condition.
This is utter bollocks, any engine with a case leak will run richer, the bigger the leak the richer it will run.
Caused by the fact that the case "pump" no longer works and the fuel air mixture isnt being transferred thru the ducts.
If the engine is then leaned up to "fix" the incorrect mixture - then it seizes.

I could have got this wrong but when he says air leak could he have been referring to a manifold air leak and if it does will this still cause it to run rich as in your analogy Wob?.
I am not challenging you. Just curious? because I always was lead to believe a manifold air leak runs lean and it always seem to on four strokes.

Piston specs here inc ring peg locations
http://www.pvlsverige.se/vrm/kolvar/kolvar.html

Also below a very old way of securing circlips. Which I think its quite cool. Clever bugger that Phil Irving

[wobbly]

A leak between the carb and the reed or any intake will always add air going into the engine and create a lean condition.
A leak anywhere in the case, be it a gasket, a seal, or a pin hole in a casting will cause the engine to run rich.
Problem is that they then seize for no apparent reason when the jetting is then "fixed".
So its always wise to make a set of blanking plates and or use a rubber bung with a bolt that expands it into the pipe manifold, so that a leak down test can ensure no case problems exist.

[bucketracer]

247722


Last attachment contains past the main jet 3 times I believe this was raised earlier.

When TeeZee first talked about fuel passing the main jet three times. SS90 was most adamant that it couldn’t possibly happen as he had never seen a carb fog at max power on a 2-stroke, you know, real life experience and all that.

And he made his usual song and dance about having to have real Industry experience to know what your talking about.

<iframe src="http://www.youtube.com/embed/KcNfci9OruU" allowfullscreen="" width="420" frameborder="0" height="315"></iframe>

This is TeeZee’s bike making 27-28 hp complete with carb fog at max power. If its not fuel passing the main jet at least three times then what is it, maybe SS90 the Industry Man himself could tell us.

247723

After seeing the fuel line being sucked down in the vid, TeeZee added the filter/header tank, it works a treat and keeps the line full.

[TZ350]

The fuel tank had a 4mm hole drilled through the fuel cap for an extra breather and I expected fuel flowing down from the tank to keep the 6mm id fuel line full as it would be more than the smaller float needle valve could pass.

Yes, I was pretty shocked when I saw the air in the fuel line during heavy runs on the dyno.

The fuel line seems a resionable size, there was a good head of fuel in the tank and because of the big bottom entry on the tank for the fuel line it seemed unlikely that the carb could be draining the fuel line faster than the fuel tank could re-fill it, and if it did where did the bubles come from, outgassing? possible, but my guess is the air was getting into the fuel line via the float needle valve.

The bubbles look like they are being sucked down in the vid but I think they are just denoting where the incoming air has almost completely filled the line forcing fuel to run down the inside walls, its easier to see in the flesh than the vid. And the bubbles go back up again as the accumulated air bleads through to the tank.

And if air is going up into the fuel line that way it must be reducing the area left for fuel to flow into the fuel bowl, what should have been a one way highway for fuel is being reduced to two smaller lanes going in opposite directions.

Anyway thats my take on it, and if any one has seen this before and can tell me more I would be very interested.

Its a scary thought, the float needle jet becoming the main restriction of fuel being carburetted to the engine.

Whatever, the modified filter header tank stopped it.

[husaberg]

As Dave said earlier on Yamaha were instrumental in keeping the 500GP's interesting.

[husaberg]

As Dave said earlier on Yamaha were instrumental in keeping the 500GP's interesting.

As Husaberg said Dave said earlier on Yamaha were instrumental in keeping the 500GP's interesting.

[TZ350]

Piston specs here inc ring peg locations
http://www.pvlsverige.se/vrm/kolvar/kolvar.html

This is real Gold

[husaberg]

This is real Gold

There is a Zundapp piston in there that looks like it would work in a Bucket.
The catalog was found in a link buried in a thread somewhere. I have never tripped over it in Google.

This seems to be the home page and it is a awesome resource http://translate.google.co.nz/translate?hl=en&sl=sv&u=http://www.pvlsverige.se/vrm/index/index22.html&ei=fZ2HTpTVKuiziQfO67WhDw&sa=X&oi=translate&ct=result&resnum=3&ved=0CC4Q7gEwAg&prev=/search%3Fq%3Dhttp://www.pvlsverige.se/vrm%26hl%3Den%26biw%3D1280%26bih%3D827%26prmd%3Dim vns

They do carbs as well http://translate.google.co.nz/translate?hl=en&sl=sv&u=http://www.pvlsverige.se/vrm/mikuni/mikuni.html&ei=wI-HTtjgNsyTiQfHhqG8CA&sa=X&oi=translate&ct=result&resnum=2&ved=0CCQQ7gEwAQ&prev=/search%3Fq%3Dhttp://www.pvlsverige.se%26hl%3Den%26biw%3D1280%26bih%3D8 27%26prmd%3Dimvns

[wobbly]

Small problem you have overlooked with that piston.
Its only 50mm long and with a 100cc bucket we are usually using the 50.6 stroke cranks, thus the exhaust port will be exposed to the case when the piston is at TDC, unless you raise the port floor.
The 1.2mm ring is too wide to be running over 14000 rpm as well, and the huge hole they have around the pin will create port linking issues with a wide T port or a big 3 port setup.
The 50mm oversize RM85 pistons I got are 51mm long, just enough to work OK, as are the 50.5mm CR85 +3mm ones for Mikes engine.
Also the TM carb is an old design, one of the first semi flat slide carbs - the later TMX and PWK types flow alot more air due to much superior slide shape.

[TZ350]

The 50mm oversize RM85 pistons I got are 51mm long, just enough to work OK, as are the 50.5mm CR85 +3mm ones for Mikes engine.

Sample image and text from husabergs link. The RM85 will be there some place and lots of other pistons there to look at too.

247766

Wössner smidd kolv till Kawasaki KX 85 8102DA-8102D500

Wössner Smidd kolv passande Kawasaki KX 85 2001-08
Två smörjhål på kolven mot bommen
Kolven finns i sex olika storlekar från standard till största ÖD.
48,45 48,46 48,47 51,95 52,45 52,95mm.
Höjd totalt 54,30 mm.
Höjd till kolvkant 52,00 mm
Avstånd från centrum kolvbult till övre kolvkant 26,00 mm.
Kolvbultsmått 14 x 38,60 mm.
En chromemolyring höjd 1 mm.
Kolvringslåsning klockan 5.
Kolvbultslåsning medföljer

Pris 975 kr

husabergs link


Piston specs here inc ring peg locations
http://www.pvlsverige.se/vrm/kolvar/kolvar.html

[husaberg]

Small problem you have overlooked with that piston.
Its only 50mm long and with a 100cc bucket we are usually using the 50.6 stroke cranks, thus the exhaust port will be exposed to the case when the piston is at TDC, unless you raise the port floor.
The 1.2mm ring is too wide to be running over 14000 rpm as well, and the huge hole they have around the pin will create port linking issues with a wide T port or a big 3 port setup.
The 50mm oversize RM85 pistons I got are 51mm long, just enough to work OK, as are the 50.5mm CR85 +3mm ones for Mikes engine.
Also the TM carb is an old design, one of the first semi flat slide carbs - the later TMX and PWK types flow alot more air due to much superior slide shape.

Party Pooper
I must admit it looked short. But I recalled the MB100 was about 50mm so I thought it would be sweet.
On closer Exam the MB100 is about 60mm Whoops.Over 14000 really?
The 1.2mm are a bit wide by competition standards but they are Heaps narrower than the std Mb100/H100 rings which are 1.5mm keystones.

I posted the old Mikuni as it was a ready made kit for the Honda bucket in a legal size for a 125cc AC bike.
If you like the newer carbs here's some for you.
They are on the same site.
Did you have a look at the link to the piston site Wob?

It is probably the best 2 stroke piston site I have seen?

As well as plenty of Rod stuff and lots of other good stuff.

[TZ350]

....Whoops.Over 14000 really? ......

247783

Speedpros,( red line ) is kissing 13,500rpm and I think the new design calls for 14,000+.

The other lines are my attempts to keep up with the big boys.

[koba]

The other lines are my attempts to keep up with the big boys.

That green one is looking pretty good!

I'm still not convinced any of these super powered 25hp+ motors are going to be rideable on a kart track by anyone but a super fast rider with all the best handling and suspenders.

Different story on a big track tho... oh look the GP an BOB are run on big tracks!

Nevermind my babbling, as you were...

[husaberg]

That green one is looking pretty good!



Different story on a big track tho... oh look the GP an BOB are run on big tracks!

Nevermind my babbling, as you were...

F5 Anyone
This left me speechless

It is a Honda 50 converted to Rotary valve and a LC Derbi top end and Minerili crank.

Whats the go with these bearings?

http://translate.google.co.nz/translate?hl=en&sl=sv&u=http://www.pvlsverige.se/vrm/index/index22.html&ei=6RiITqL7LqbkmAXduKwr&sa=X&oi=translate&ct=result&resnum=1&sqi=2&ved=0CCAQ7gEwAA&prev=/search%3Fq%3Dhttp://http//www.pvlsverige.se%26hl%3Den%26biw%3D632%26bih%3D35 0%26prmd%3Dimvns

Go to the bit with the face and the thumbs up.

[koba]

F5 Anyone
This left me speechless

It is a Honda 50 converted to Rotary valve and a LC Derbi top end and Minerili crank.


Jeebus! that is pretty flash looking stuff!

EDIT: So that MB50 cases yeah?

[Henk]

And here am I, dicking about with 30 year old XL100 motors to try and throw some sort of F5 bike together :facepalm:

[koba]

And here am I, dicking about with 30 year old XL100 motors to try and throw some sort of F5 bike together :facepalm:

Sounds all G to me.

[husaberg]

Jeebus! that is pretty flash looking stuff!

EDIT: So that MB50 cases yeah?

I think so, But I havent seen the NSR50/80 close up though so not sure.
There was a ns50f AC08 that had the saame engine as the NSR50/80 that was very similar looking motor to the mb AC01 only liquid cooled off the primary drive.I have never seen a MBX50engine either AC03

[husaberg]

And here am I, dicking about with 30 year old XL100 motors to try and throw some sort of F5 bike together :facepalm:

The Mb50. If that was it is indeed based on. Is also 30 years old now.
In-fact probably closer to 40 if you count the MR50 engine.

[koba]

The Mb50. If that was it is indeed based on. Is also 30 years old now.
In-fact probably closer to 40 if you count the MR50 engine.

That's a minter!

[koba]

Although the cases do look significantly different to an MB50.

[husaberg]

Although the cases do look significantly different to an MB50.

"SQUINT HARDER" Then :lol:

Well I guess it would be a lot easier for me, being Asian and all :laugh:

Definitely cousins. I think anyway, The MR50 was pre reed Mini Elsinore. Points ign Has no balancer and not many gears
i think.

Pics are MR50 MB5/H100 and Air Cooled CR80.
PS I never noticed the CR80 clutch set up was different to the MB/H100 and I have a Cr80 AC motor bits in the shed.

[wobbly]

E15 bearings are "magneto" shaft units that slide apart - yes they are angular contact.
Used in electric motor shafts and in some bikes as tripple tree steering head bearings, they need some form of end float adjustment.

Thanks for the links - great to have info like that on so many parts

[husaberg]

E15 bearings are "magneto" shaft units that slide apart - yes they are angular contact.
Used in electric motor shafts and in some bikes as tripple tree steering head bearings, they need some form of end float adjustment.

Thanks for the links - great to have info like that on so many parts

Yes they looked a little like the bearings Suzuki use in some steering heads But What is the advantage as a main over a std Bearing, less Fiction?
I couldn't figure out the magnetic bit So its (Magneto Bearing) I guess that Google translate got a bit lost in Translation from Swedish.
Had you heard of this Guy Wob?
Your Right there is some neat stuff and info there.
He obviously makes great use of his long winters.
The MB disk Valve seems available as a kit too.
Here is a forum he is on.
Best of all he seems to speak English too, by the look of it.

http://50iniepoca.forumfree.it/?t=43987929&st=75

[wobbly]

Had a look at the forum, his crankcase stuffing looks like the RGV100 im doing.
Wierd, he says its best to have as short a RV inlet as possible - I agree, but then he bolts on a poxy old round slide Mikuni.
Maybe in the rules??.

The angular contact bearings have the least friction - as they have a very small contact patch, and maybe this is an issue in a high rpm 50cc,but they also need real precision setup with shimming or a threaded end float arrangement.
I would use Microblue treated C4 radial balls, much easier, as I have dyno'd these as worth nearly 2 Hp in a 50 Hp 125.

[husaberg]

Had a look at the forum, his crankcase stuffing looks like the RGV100 im doing.
Wierd, he says its best to have as short a RV inlet as possible - I agree, but then he bolts on a poxy old round slide Mikuni.
Maybe in the rules??.

The angular contact bearings have the least friction - as they have a very small contact patch, and maybe this is an issue in a high rpm 50cc,but they also need real precision setup with shimming or a threaded end float arrangement.
I would use Microblue treated C4 radial balls, much easier, as I have dyno'd these as worth nearly 2 Hp in a 50 Hp 125.

Yeah I did see that with the crankcases, the carb is a period rule thing.
Those angular contact bearings. Didn't Ducati used them in the 851/916. But they need Preload in the cases as well. Is that right?

The water pump control and the ignition are interesting too.Very Jarcar/Dicksmith.

Ps what did you think about the Phil Irving book Gudgeon pin mod.The YZR500 was I thought a good article YAmaha were very generous I will post a Swiss auto writeup later I never knew they were that light.

[TZ350]

Been playing with a friends nearly stock MB100 tonight, modes were pipe, razed compression, reed and carb.

247836

Dialled it in best we could with ignition and jetting but suspected it was a bit over compressed so we put a gauge on it, 195psi cranking, Blue line.

A quick bit of machining and 180psi Red line. (My own bike is 160psi at 13.5:1 uncorrected)

And even more skimmed out of the combustion chamber 130psi Green line.

Interesting to see how the power changed with compression.

Next move is to check the port time areas and pipe TL as it looks like there is a bit of a missmatch somewhere and cc it properly for around 14:1 and dial the CR in using the dyno.

I have often used a dyno to dial in the ignition and main jetting but have never thought of actually dialing in the compression ratio on the dyno by making small adjustments to the CR untill I have found the CR sweet spot .... :facepalm: but its an obvious thing to do realy.

[ac3_snow]

I have got a little bit done this morning. Fitted the crank up in my 'lathe' and polished it with emery cloth so the bearing now slides on with hand pressure.

Then got stuck in measuring everything up, was interesting. One question regarding the crankcase volume.... There is space between the piston port/reed block and the carb, I would consider this area to be the intake manifold. Is this part of the measurement when calculating crankcase volume? If so then it changes things considerably.

What I ended up with was...

Primary compression ratio (not including intake manifold) 1.37

Compression ratio 14.67

My thoughts are that the PCR is about right.. and compression ratio is not too bad, think from memory it gives me about 160psi. Only issue is the squish I think is still 1mm, will have to check this out once I do the final assembly, and perhaps reshape the head to reduce the squish and not up the compression.

Other pic is my plug after melting the piston :laugh:
247858247857

[F5 Dave]

I have often used a dyno to dial in the ignition and main jetting but have never thought of actually dialing in the compression ratio on the dyno by making small adjustments to the CR untill I have found the CR sweet spot .... :facepalm: but its an obvious thing to do realy.

Not everyone has a lathe in the dynoroom.
re above, so did you find the best ignition timing for each CR? it can change quite a bit for each head shape (although power can stay the same -can not will). A change in baffle cone may affect your 'sweet CR spot'

[wobbly]

Everyone uses the chamfered pin with plain clip now - but for years we had to cut the inner leg off TZ clips and add the chamfer to prevent the clips from popping out.
Dont know if Irving was the instigator of the idea, but it works a treat.
The angular contact bearings I dont think are a good idea for mains - as any side float will translate into vertical slop as well, so they must be run with preload.
Sort of the reverse of floating the crank - and thats worth easily replicated free Hp.

Primary com of 1.37 would be about right for the average transfer duct and port geometry being run.
If the descending piston compresses the volume, then its part of the case compression if its connected when the piston port is closed.
That plug looks way too hot for the application as well.

[ajturbo]

could this be sleeved down to 150cc????

http://www.asphaltandrubber.com/news/erik-buell-racing-considering-250cc-learner-bike/

:innocent:

[Yow Ling]

could this be sleeved down to 150cc????

http://www.asphaltandrubber.com/news/erik-buell-racing-considering-250cc-learner-bike/

:innocent:

I think you could get a special exemption to leave it at 250cc, cant see it even bothering a mighty FXR

[husaberg]

Everyone uses the chamfered pin with plain clip now - but for years we had to cut the inner leg off TZ clips and add the chamfer to prevent the clips from popping out.
Dont know if Irving was the instigator of the idea, but it works a treat.
The angular contact bearings I dont think are a good idea for mains - as any side float will translate into vertical slop as well, so they must be run with preload.
Sort of the reverse of floating the crank - and thats worth easily replicated free Hp.

Primary com of 1.37 would be about right for the average transfer duct and port geometry being run.
If the descending piston compresses the volume, then its part of the case compression if its connected when the piston port is closed.
That plug looks way too hot for the application as well.

With the Holed piston I suppose it would have made it easy for snow to measure the comp ratio so something good will come from the blow up I guess.
I think snow had mentioned the plug was a NGK 6 rather than a 9 which I would have thought would be more suitable for a tune such as Snows

The chamfer on the gudgeon.
I understand pretty much every pin is like that now. I just never knew that was why. I just thought it was for easy assembly and sress relief.
I never would have guessed that retaining the circlips was what it was for.

I mains were a bit of a surprise, but I think he said somewhere thay were worth a hp on a 50 but I don't know what bearing he compared it to.
With a the floating crank one think I have never been able to get my head arround is why wouldn't that cause problems with the disk valve clearances?Or is it not done on that side of the crank on a RV.

On his site it also says to use long bits of solder in a cross pattern for the squish checking. I always used to use 4 bits of short but his way is far neater and probably more consistent results not to mention easier with a angled cylinder like a MB100.

RE the Harley they would be hard to pass as they take interesting lines and are very wide I guess the 250 would go better than a stock EVO though.

Last pic is that an Airbox for a disk valve motor? If not what is it?

[teriks]

If you hand me the text in Swedish I might be able to translate it to something more useful ;)

[wobbly]

Re the floating crank,in all the race engines I have done the RV floats on a boss thus any movement of the crank has no effect.

[TZ350]

Not everyone has a lathe in the dynoroom.


247993

Not every one has a natural gas tubocharged V8 Cat powered 1,200 m3/hour CNG compressor in the dyno room either. These beasts get shipped from New Zealand to all around the world.


... so did you find the best ignition timing for each CR? it can change quite a bit for each head shape (although power can stay the same -can not will).

Yes... roughly optimized for each CR change, but there was not much in it. Like you, I have found that bigger changes are required with different head shapes. Mine with its dished piston and tight squish is about 14 and the open chamber engines we run are about 26 deg BTDC.


... A change in baffle cone may affect your 'sweet CR spot'

Agreed, more of a supercharging/plugging effect from the pipe will require a lower CR.

I thought it was hard enough with just ignition and jetting, and now compression, to many variables to lay out in a matrix and work through one by one, so I have to take intuitive steps and hope the guesses go in the right direction.

[F5 Dave]

. . .
I thought it was hard enough with just ignition and jetting, and now compression, to many variables to lay out in a matrix and work through one by one, so I have to take intuitive steps and hope the guesses go in the right direction.
Tell me about it, back to the dyno tonight having made some changes that MUST be better; only to find a bunch of missing power & after going in circles will have to go back tail between legs to the original set up & see if indeed steel reeds are better than the two thickness's of CF I have trialled. . . or that I have lost power elsewhere & in between am trialling every combo of ign & jet size find what that is. To make it worse the starter doesn't work so I have to pull the bike off the dyno bump it & reattach for every run. Joy.

[ac3_snow]

Re the floating crank,in all the race engines I have done the RV floats on a boss thus any movement of the crank has no effect.

Pardon my ignorance, could you please explain this for me in laymans terms?

[TZ350]

Tell me about it, back to the dyno tonight having made some changes that MUST be better; only to find a bunch of missing power.

Yep I have often taken a bunch of power and made it into a much smaller offering before getting it right.

[TZ350]

Made a small adapter plate tonight to fit the pumper carb hard up against the case, can't get any shorter than that. Also set the pop off to 10psi. That lever and dam spring is sure fiddly and now to figure out how to connect the throttle cable as it now pulls in the wrong direction??????

[husaberg]

and now to figure out how to connect the throttle cable as it now pulls in the wrong direction??????

Should be a good may to decrease lap time as you will have to forcibly roll the throttle off to slow down.I think you could disable the brakes to at the same time as they only slow you down probably no good on a race bike anyway.:blink:
Not a bad site here, with some interesting stuff. It was the naughty boy racing site.

http://www.speeddemonracing.com/articles.html

[koba]

Made a small adapter plate tonight to fit the pumper carb hard up against the case, can't get any shorter than that.

No float bowl to froth up with the solid mounting too!

[bucketracer]

..... I think you could disable the brakes to at the same time as they only slow you down probably no good on a race bike anyway.:blink:

I have seen TeeZee ride a bike to a good finish in the wet after crashing and breaking the front break lever right off.

[husaberg]

I have seen TeeZee ride a bike to a good finish in the wet after crashing and breaking the front break lever right off.

I remember a story of a GP rider 250 I think who broke his right wrist.
Well that buggered him up for racing so he got the mechanics to swap over the the brake and throttle over so he could still ride and hopefully salvage some points.
He lasted one or two laps until he applied the clutch (now Front brake) during a full throttle shift in practice. He then decided maybe it would be better to wait till the cast was off.
I think Schwantz just used to rip the cast off and ride anyway.

RE the front brake a little trick is to put a plastic sleeve under the clamp so in the event of a crash the brake assembly can pivot a bit.
Another is to have the lever well inside the length of the clip-on's as well overlooked on quite a few bikes some people also drill just bellow the ball as a sacrificial bit to snap rather than further down the lever. To finish first first you have to finish I guess.

[bucketracer]

When I was helping Thomas with measuring air flow through different carbs and looking for ways to improve them he showed me that it was much easier to get good flow with a small step < 1mm between carb and manifold than you usually could by trying to get a perfectly good match.

248015

The flow with a small step and the best match we could make was the same, a slightly imperfect, perfect match flowed noticeably less air than a definite small step did.

248014

TeeZees carb with a small even 0.5mm step all around the edge will make it easy to take off and refit without loosing any air flow at the joint through any slight miss alignment.

[husaberg]

If you hand me the text in Swedish I might be able to translate it to something more useful ;)

Luftbox till förgasare

Specialtillverkad luftbox med över och underdel som bildar botten mot förgasaren.
Boxen är kanon till slidmatade motorer eller crosshojar där man vill ha filtret på ett mer skyddat ställe utan att förstöra varken motorkarakterestik eller körning.




Mikuni Powerjet PRO
MEG-024 med elektrisk styrning


Universalkit för alla typer av förgasare. Kitet är till för att ge extra bränsle under accelaration då det behövs som mest med bränsle. Det här kitet är det som topptrimmarna använder tillsammans med programeringsenheten till tändboxen eller liknande. Den aktiveras då pipan börjar dra för att stänga av då man har paserat max vridmoment. Därefter behöver motorn gå magrare igen.

En annan användbar arbetsplats för den här magnetventilen är att använda den på lustgasaplikationer. Då kan man placera den mellan trotteln och insuget. Ventilen kan då ge motorn extra bränsle vid avslaget då resterande lustgasmängden läcker in i motorn efter avstägningsventilen till lustgasen. Annars är risken för haverier överhängande på grund av uttorkning av cylinderväggar och lager.

Powerjet munstycket måste alltid beställas separat av kunden.

Beställningsnummer MICPJ 30 upp till 100 Du hittar munstyckena på ett annat ställe här på sidan.

Thanks for the offer most appreciated.
I struggle enough with Engerish.

[Buckets4Me]

just heard that one of the test riders for team E.S.E is off to japan



" He will be riding a Suzuki GSX-R600 for the Yoshimura R&D Team "

" Following informal discussions with Yoshimura Japan’s President, Fujio Yoshimura, Jaden has been offered a test opportunity in the 600cc Super-Sport class, a round of the National Japanese Championship. His recommendation came from New Zealand’s own 2 times World Champion Graeme Crosby "

" A bonus for Jaden will be the chance to ride a Yoshimura Suzuki GSX-R1000 WSB - World Super Bike. "


http://brm.co.nz/articles/hassan-to-race-in-japan.html

[teriks]

Some odd Swedish there as well, I'll give it a try..

Luftbox till förgasare

Specialtillverkad luftbox med över och underdel som bildar botten mot förgasaren. "Specially made air-box consisting of an upper and lover part, forming a bottom against the carb"
Now, I dont understand that "forming a bottom against the carb"-bit myself..

Boxen är kanon till slidmatade motorer eller crosshojar där man vill ha filtret på ett mer skyddat ställe utan att förstöra varken motorkarakterestik eller körning. Anyway, it's intended for disc valved engines, where you want to move the air filter to some more protected location. Then there is a part about the air-box not ruining engine characteristics or drive-ability something.

I'll get the rest when not at work..

[cotswold]

Google translated it as


Custom made luftbox over and bottom forming the bottom of the carburetor.
The box is great for slidmatade engines or motocross bikes where you want the filter to a more protected place without destroying either motorkarakterestik or driving.




Mikuni Powerjet PRO
MEG-024 with electrical control


Universalkit for all types of carburetors. The kit is designed to provide extra fuel during accelaration when you need it most with fuel. This kit is what topptrimmarna use with the programming device to the ignition box or the like. It is activated when the barrel starts to pull that off when you have Pasera max torque. Then have the engine run leaner again.

Another useful work for this solenoid valve is to use it on lustgasaplikationer. Then you can place it between the throttle and intake manifold. The valve can then give the engine extra fuel for the refusal when the remaining amount of nitrous oxide leaks into the engine after avstägningsventilen to nitrous oxide. Otherwise, the risk of accidents imminent due to dehydration of the cylinder walls and bearings.

Powerjet nozzle must be ordered separately by the customer.

Order Number MICPJ 30 up to 100 nozzles can be found elsewhere on this site.

[wobbly]

Re the PV and floating cranks.
All the engines I have worked on with a RV, the valve has a boss in the centre.
This boss slides on crank splines to give the correct rotational alignment, and also allows the blade to float in the gap between the case and cover.
Thus allowing the crank to float the recommended 0.2 to 0.3mm on the mains, has no effect on RV alignment.
Here is pic of a RV splined boss

[wobbly]

Re the lever arm height on the pumper - the free end should be set such that the middle of the arms end thickness is flush with the floor of the body.
Some say the top of the arm flush with the body floor, but most tuners raise this a little to 1/2 the thickness.

[ac3_snow]

Cheers for the explanation wobbly! I read RV and kept thinking reed valve.

Have also been thinking about getting some race gas to use in my bike this weekend, with the high compression probably not a silly idea. Any way stumbled across this site, was an interesting read.
http://dirtbike.off-road.com/dirtbike/feature/pump-gas-race-fuel-and-octane-boosters-12920.html

perhaps not all relevant as I don't think its a NZ site, but couple of points I found interesting.



The bottom line is this: let's say your motor needs 92 octane to run correctly and you fill up with 125 octane wonder gas. You will not run any faster. In fact, you might end up running slower because of a radically slowed flame front.
Guess I should sort out the squish and combustion shape soon.


Probably the single best option is to test with a hydrometer several containers of the racing gas you're considering buying. This will give you the specific gravity of the fuel, and if it varies from container to container, it will tell you a very sad story about quality control.

You can buy a gas testing hydrometer for about four or five bucks. All savvy tuners test with them BEFORE they start tuning, or if they cannot use their regular gas.


Q: What about using AV, or aviation, gas?

A: There's an old wives' tale about AV gas out of World War II and I don't know who started this, but it says that if you put AV gas in your car, you'll burn the valves. There's no doubt that aviation fuel can be used in any internal combustion engine that's driven up and down the highway at cruising speeds.

It doesn't make much sense to use it for that since it goes for something like $1.75 or $1.85 in this area, and is not easily obtainable.

A motorcycle and an airplane really live in two different environments. An airplane generally takes off, climbs to its altitude and the general outside temperature is at or below zero. Even in the summertime, it maxes out at 10 or 20 degrees above. And an air-plane does not turn high rpm. A typical prop job loafs along at two to three thousand rpm. Of course, there are some high perfor-mance exceptions. The engine just drones along at low power settings, except for take-offs.

[husaberg]

Re the PV and floating cranks.
All the engines I have worked on with a RV, the valve has a boss in the centre.
This boss slides on crank splines to give the correct rotational alignment, and also allows the blade to float in the gap between the case and cover.
Thus allowing the crank to float the recommended 0.2 to 0.3mm on the mains, has no effect on RV alignment.
Here is pic of a RV splined boss

Didn't really consider that bit did I Whoops :facepalm:

Can you give the Snow a heads up on a approx comp he should be aiming for with the bucket legal fuel with his approx spec. My gut feeling is he is still a bit OTT at the moment.

[TZ350]

248072248073248074

Ariel Arrow racer.......

I have one of these (road bike) in bits, could be a bit of fun building one of these racers up to chase the pre 76 Bennelli 240 boys.

Anyone have any Ariel Arrow engines/gearbox bits and bobs? please PM me.

Might even convert it to rotary valve and will most certainly run it on methanol.

[wobbly]

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.

[husaberg]

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.

Shit With an air cooled we can still push that high broadly speaking (of course)
I thought Snow was at the edge of the envelope at 14.67:1 Shows I know well F all. As I suspected. I would have ball parked 13.5 or so Max with a Air Cooled 125 on AV Gas.


PS I will only give you grief if the new top secret hush hush engine fails to deliver less than 35 hp at the rear wheel with a power spead that makes my husaberg look like a peaky old school 2 stroke.
When do you think you will have pics of the new baby. I hear she is cute. I haven't told the misses about her yet so I expect there will be fireworks soon. As she already thinks I am in love with another. Girls can be so jealous sometimes. Does she have a name yet? I hear she does have lovely almond eyes.


TZ I have some info for you. I will post it when I trip over it. Herman Meijer and co I think the factory one got a 3 or 7 at the TT one year. Although you may struggle against the Bennellis. I would say 30hp before radically rework is needed of the bottom end. Shit I just had a proper look at the pics, is that a Krober ignition and Twin mikunis and a Belt drive as well the gearbox. I suggest would be your greatest hurdle on that thing. Love those flanged rims. mmm........
TZ and can you Post Wob A pic of the Std rod in An Ariel Arrow. I think he would get a kick out of it.

[Kickaha]

and Twin mikunis
Wouldn't that make it ineligible for Classic register events, where does it race?

[wobbly]

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..

[teriks]

Sorry about the late reply, have been working ridiculously late the last couple of days.


Mikuni Powerjet PRO
MEG-024 med elektrisk styrning



Universalkit för alla typer av förgasare. Kitet är till för att ge extra bränsle under accelaration då det behövs som mest med bränsle. Det här kitet är det som topptrimmarna använder tillsammans med programeringsenheten till tändboxen eller liknande. Den aktiveras då pipan börjar dra för att stänga av då man har paserat max vridmoment. Därefter behöver motorn gå magrare igen.
"Universal kit for any type of carb. The kit is designed to provide extra fuel during acceleration. This kit is used by top tuners together with a programmable ignition or other electronic control. It is activated when the pipe starts to pull, and turned of when you pass max torque. At rpm's above max torque the engine needs to run leaner again."

I think the correct usage of a power jet was explained by wobbly some pages ago.


En annan användbar arbetsplats för den här magnetventilen är att använda den på lustgasaplikationer. Då kan man placera den mellan trotteln och insuget. Ventilen kan då ge motorn extra bränsle vid avslaget då resterande lustgasmängden läcker in i motorn efter avstägningsventilen till lustgasen. Annars är risken för haverier överhängande på grund av uttorkning av cylinderväggar och lager.
"Another useful application is together with a NOS-system. The power jet can then be placed between the throttle and the intake. The valve can then be used to provide extra fuel when shutting the throttle [and the NOS-valve] to prevent breakdown caused by rest amounts of NOS destroying the oil-film on cylinder walls and bearings."


Powerjet munstycket måste alltid beställas separat av kunden.

Beställningsnummer MICPJ 30 upp till 100 Du hittar munstyckena på ett annat ställe här på sidan.
"Jets have to be ordered separately. -Order no. MICPJ 30 up to MICPJ 30.
Jets are found elsewhere on the site."



Thanks for the offer most appreciated.
I struggle enough with Engerish.
Doing the translation, I just realized I struggle with Swenglish myself ;)

[husaberg]

Sorry about the late reply, have been working ridiculously late the last couple of days.

"Universal kit for any type of carb. The kit is designed to provide extra fuel during acceleration. This kit is used by top tuners together with a programmable ignition or other electronic control. It is activated when the pipe starts to pull, and turned of when you pass max torque. At rpm's above max torque the engine needs to run leaner again."

I think the correct usage of a power jet was explained by wobbly some pages ago.

"Another useful application is together with a NOS-system. The power jet can then be placed between the throttle and the intake. The valve can then be used to provide extra fuel when shutting the throttle [and the NOS-valve] to prevent breakdown caused by rest amounts of NOS destroying the oil-film on cylinder walls and bearings."

"Jets have to be ordered separately. -Order no. MICPJ 30 up to MICPJ 30.
Jets are found elsewhere on the site."
Doing the translation, I just realized I struggle with Swenglish myself ;)

Thanks very much for that. Most appreciated. Do you speak any other languages? I struggle with one. I am guessing if your originally from Sweden, You didn't move here for the hot looking Chicks.

[TZ350]

TZ and can you Post Wob A pic of the Std rod in An Ariel Arrow. I think he would get a kick out of it.


248106

Ariel Arrow rod (right side) is a similar size to a 70's TZ and has oiling slots like a racing Yamaha TZ's (road RD's did not have oiling slots). The Arrow has bushed little ends and two crowded rows of 1/4" rollers for a big end brg.

248107 248108

The Arrow crank is joined in the middle by a taper and key held together by a big cap screw.

The whole motor can be dissasembled, heads/barrels off, crank and gear box taken out for a major overhall without removing the cases from the bike.

[husaberg]

248106

Ariel Arrow rod (right side) is a similar size to a 70's TZ and has oiling slots like a racing Yamaha TZ's (road RD's did not have oiling slots). The Arrow has bushed little ends and two crowded rows of 1/4" rollers for a big end brg.

248107 248108

The Arrow crank is joined in the middle by a taper and key held together by a big cap screw.

The whole motor can be dissasembled, heads/barrels off, crank and gear box taken out for a major overhall without removing the cases from the bike.

Well I be buggered. I knew about the center joint (Hence my 30hp reference)Looking back the twin engine I was thinking with the even odder centre joint is the Exselsier twin 2 stroke which I think in hindsight more like a Harley/aermacchi twin 250.
but I always thought (The Ariel) had hollow oval section rods.
Edit and according to this most of them did is yours an early arrow or is it a leader or is the article toss.EDIT

With the Alcohol fuel and a bit of modern attention. I guess based on my wrong assumption of 24hp being the max of your AC125.
I guess Will have to ramp up the target to 38hp.

But it stil leave you with a Burman Gearbox though whats your plan there to get around that one. http://www.novaracing.co.uk/ariel-arrow.htm
http://www.flickr.com/photos/professorpigeon/5601273533/
http://3.bp.blogspot.com/_VDCGGBYmNCk/Sur3mHWuVCI/AAAAAAAAIMw/gHFmCFuhjnA/s1600-h/3465060760_837215130b_o.jpg
http://www.google.co.nz/imgres?q=ts5+Ariel+Arrow&hl=en&biw=1280&bih=827&tbm=isch&tbnid=fRXVKBKXXhblvM:&imgrefurl=http://heinkelscooter.blogspot.com/2010/07/please-dont-let-me-be-misunderstood.html&docid=oVsvG_blRaQ8AM&w=799&h=533&ei=37CPTsS6JqHmmAXE_8QR&zoom=1&iact=rc&dur=422&page=1&tbnh=147&tbnw=197&start=0&ndsp=28&ved=1t:429,r:5,s:0&tx=148&ty=109
http://www.k21.co.uk/smf/index.php?action=printpage;topic=148.0
http://www.flickr.com/photos/53591907@N00/2253477067/in/set-72157603882388495/
http://www.t20suzuki.com/

I was most interested in the pipes on the old Arrow (bellow) as they still look almost right today bar the stinger and the plain design.
As well as the current then philosophy regarding primary comp and other design aspects.

I guess you are aiming for post classic racing rather than CMRR.

I would go with a Silverstone/Outon greeves but in BRG or a stamaker powered replica.
http://motorbike-search-engine.co.uk/classic_bikes/1965-greeves-250.php
http://www.flickr.com/photos/smeracing/3033030032/in/photostream/
http://www.kellymotodepoca.com/images/Greeves_Silverstone_65.jpg

Added bellow and below again is some of the Aprilia development story leading to the first 250 GP championship with Max (I'd Do that for a dollar) Biaggi

[teriks]

Thanks very much for that. Most appreciated. Do you speak any other languages? I struggle with one. I am guessing if your originally from Sweden, You didn't move here for the hot looking Chicks.
No problem, been lurking this excellent thread for some time and finally found something I could give back. No additional languages unfortunately.

You are right in that I'm originally from Sweden, only I still live here. So no, I did not move for the hot chicks, I didn't move at all.
Now, this time of year with winter approaching...

[husaberg]

No problem, been lurking this excellent thread for some time and finally found something I could give back :)

You are right in that I'm originally from Sweden, only I still live here. So no, I did not move for the hot chicks, I didn't move at all. Now, this time of year with winter approaching...

Hello
Welcome to the thread I am sure the Auckland boys will give you an official welcome as soon as they stop watching the rugby.

Had you heard of the Swedish tuner I was linking the posts too
Roffe is it?

Neat stuff below.

[teriks]

I feel welcome as it is :)

No I haven't heard of Roffe, but that might say more about me than of him.
EDIT: To clarify, my main interest is two-stroke racing technology in general, not road racing motorcycles. So, basically I don't have a clue about what goes on in vintage racing etc.
(Flying radio controlled pylon racing with 6.6cm^3 two-strokes. Actually Fritz Overmars was involved in the development of the type of engine I use. He mentions some of it here: http://www.pit-lane.biz/t117p390-gp125-caracteristiques-aprilia-rsa )

[TZ350]

Well I be buggered. I knew about the center joint (Hence my 30hp reference) but I always thought they had hollow oval section rods.
Edit and according to this most of them did is yours an early arrow or is it a leader or is the article toss.

Not sure the joint will be a problem, its a good taper, looks strong guess we will find out in time.

Very interesting artical, they were sure onto 2-stroke development in the 60's.

My photos did not do the Ariel rod justice, I don't think its hollow but in cross section it is a slim oval, well finished.

248138

249cc 1960 Ariel Arrow - George Brown Sprint Special

Held the flying Kilometre speed record at 122.45mph. http://www.flickr.com/photos/gordoncalder/4600149198/

248139

The Arrow on the line.

George also Built the Super Nero Vincient Sprinter:- http://www.myvincent.co.uk/people/george_brown.php

248141

[TZ350]

Gee, page 340 allready I will have get all the tec stuff from the last ten pages together again and post it here.


Speedpro has won the race to be the first documented useful Bucket engine at 30rwhp


Muriatic Acid is used for getting alloy smear of cylinder walls.


Muriatic Acid, aquas solution of Hydrochloric acid

From Wiki
Hydrochloric acid is a solution of hydrogen chloride (HCl) in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid. Also called muriatic acid, or historically spirits of salt, hydrochloric acid was produced from vitriol (sulfuric acid) and common salt.

I think this is what is in those green bottles of soldering salts that you can get at hardware stores.


Case reed engines always used to have large volumes,and the RG when a 125 was too big anyway - so reducing the swept volume down to 100cc means we run into even more of an issue.
The latest engines like CR250 have a very small ,wide rectangular "window" from the reed box into the case,so I am trying to replicate something similar. Edit - read here - interesting 2T developments http://www.european-2strokecup.com/


I was just pointing out that the idea of using water, great as it may be in theory, and on a dyno when looking for bottom end, it "works" just fine.
But in a controlled test to see if its was useful, it failed, as the systems effect had to be reduced so much that any gain in bottom end was still offset by a loss in the top end.
As Burgess said, when the effect was useful, it took too long to reheat the pipes.
My thoughts, from the testing I did with a PV and ATAC operated separately ( instead of combined together as many MX engines have now) is that this works real well with no down sides at all, and is easy to implement.


C4 isnt just the end float - its the total radial clearance.
Usually its designed in for where the bearing is pressed onto a shaft ( expanding the inner race) and pressed into a housing ( crushing the outer race).

In our application it also gives the case the ability to move around due to heat expansion and not take up all the end float.

Floating at least one inner race allows the crank to self centre and reduces rolling friction heaps, doing both with a set amount of total end movement is even better.


Just a small point re main bearings.
You should have the crank floating - ie spin the crank in a lathe with the rod taped down and polish the main journals so that the bearing inner race just slides on by hand.
Some engines have one end locked in place by the drive gear, but then I just float the other side.
In fully floating cranks shoot for a min of 0.2mm and a max of 0.3mm side clearance by shimming behind the bearings,or machining the step on the journal back ( or deepen the case pocket.
And always use C3 or C4 fit bearings,fiber high speed cages are best ( expensive) followed by plastic, I would never use a steel cage in a race engine.
You would be amazed how free a floated crank spins.


I now have sets of FXR 150 cam sprocket verniers adjusters for sale. I do an exchange with your sprockets as they need to be drilled and slotted for the verniers.

Each tooth on the sprocket is 10.6 degrees. The verniers split the 10.6 degrees into 10 equal measurements. The disks labelled 0-5, 0 being 0 degrees and 5 being 5.3 degrees. To get from 5.3 to 10.6, you advance the sprocket 1 tooth and put the verniers in back to front.

The verniers can be changed without removing the sprocket from the camshaft. Very easy.

The exchange set is $85


The DR200 I think is a no go. From Memory the FXR150 is a 30mm pin like a Honda.
KTM do a lovely bearing but you can't use that. KTM also do a nice strong rod but can't use that either.
There is a yummy MMC one that weighs only 98 grams as well but you can't use that either.Unless you custom order it then it would be legal?


Anyway I digress here is a nice 37mm big end long rod SR125 in the first list
http://www.mxcomposites.com/con_rod.php
http://www.connectingrod.com.tw/ktm.htm
http://www.pro-x.com/downloads/Technical.pdf
more rods here for the inquisitive types
http://www.kevinbreedonracing.co.uk/products_conrods.asp
http://www.connectingrod.com.tw/honda.htm
http://www.samarin.nl/webshop/index.php?act=viewCat&catId=32
http://www.tkrj.co.jp/
http://findebookee.com/c/connecting-rod the one is capt

Here are some one of them I was going to use for the original stroker xr200.

249718249719249720


A clear reason?

Direct from MNZ website

24 ROAD RACING - MINIATURE

24.1 The Miniature Road Racing class or `Bucket Racing’ as it is also known, shall be
deemed to include solo motorcycles and sidecars.

24.2 Motorcycles Technical:

24.2.1 Solo motorcycles shall have two engine capacity classes:
F4 2 stroke 55-100cc
2 stroke 55-125cc air cooled
4 stroke 55-150cc
F5 2 stroke 0-50cc
4 stroke 0-100cc air cooled

24.2.2 Sidecars shall have one engine capacity class:
2 stroke 55-100cc
2 stroke 55-125cc air cooled
4 stroke 55-150cc

24.2.3 The maximum capacity for rebored engines shall be:
F4 2 stroke 55-100cc - 104cc
2 stroke 55-125cc air cooled - 130.5cc
4 stroke 55-150cc – 158.09cc
F5 2 stroke 0-50cc - 53cc
4 stroke 0-100cc - 104cc

24.2.4 Engines must be derived from non-competition motorcycles. Motocross, Road Racing,
Enduro and Go Kart motors and transmission parts are not permitted. There shall be
no restriction on the make, type or design of carburettor, ignition, exhaust, piston,
cam, valve springs or cooling system except for class eligibility. All engines must be
normally aspirated except F4 4 stroke engines of less than 100cc capacity, which may
be turbo or supercharged.
F4 2 stroke engines over 104cc are restricted to carburation equivalent to a single
24mm carburettor, F5 4 stroke engines over 53cc are restricted to carburation
equivalent to a single 20mm carburettor.

Link http://www.mnz.co.nz/download/2010_MoMS_Chapter_24_Road_Racing_Miniature.pdf
Or http://www.mnz.co.nz/competitionrules.aspx

Definitive I Think.

This Bucket Engine list was put together by Malcolm McNabbs.

The following bikes are possible buckets.
Some need more modification than others to make them competitive but all are possible starter bikes.

F5 2 stroke
Aprilia RS50
Suzuki RG50
Suzuki RMX50
Suzuki A50
Suzuki AC50
Suzuki AP50
Suzuki TR50 Street Magic
Yamaha RD50
Yamaha RZ50
Yamaha TZR50
Honda MB50
Honda MBX50
Honda MT50
Honda NS50
Derbi 50
Gas Gas 50SM

F5 4 Stroke
Honda CB100
Honda CT90
Honda XL100

F4 2 stroke
Suzuki DS80 perhaps (legality questionable)
Suzuki T90
Suzuki RV90
Suzuki A100
Suzuki AX100
Suzuki GP100
Suzuki GP125
Suzuki TC100
Suzuki TF100
Suzuki TS100
Suzuki TF125
Suzuki TS125
Suzuki T125 stinger
Suzuki GT125 (would need carburation mods to be legal)
Suzuki RGV150 (sleeved to 125cc)

Honda MB100
Honda H100
MT125 perhaps (legality questionable)
Honda NSR80

Yamaha DT100
Yamaha LS2 100
Yamaha YB100
Yamaha RS100 & 125 Yamaha
Yamaha RD125 twin
Yamaha AS3 125
Yamaha RX125
Yamaha DT125

Kawasaki AR80
Kawasaki K100
Kawasaki KV100
Kawasaki G4TR100
Kawasaki KH100
Kawasaki KH125
Kawasaki KV125

Derbi 80

F4 4 Stroke
Honda CG110
Honda CB125 (single)
Honda CB125T (Twin)
Honda CBR150
Honda TL125 (Trials version of CB125)
Honda GL145
Honda XL 125?
Honda CG125
Honda SL125
Honda CBR125
Honda CBR150

Suzuki GN125
Suzuki GS125
Suzuki DR125
Suzuki FXR150

Yamaha YZFR15
Yamaha YZFR125?

Donor Chassis The following bikes are not eligible to be used but can be used for donors of frames and running gear.
Honda RS125 (GP Bike)
Yamaha TZ125 (GP Bike, Havn't seen one)
Aprilia RS250 Aluminium Beam Frame
Suzuki RGV250 Aluminium Beam Frame
Suzuki RG250 Aluminium Perimeter Frame
Honda NSR250 Aluminium Beam Frame
Honda NS250 Aluminium Perimeter Frame?
Yamaha TZR250 Aluminium Beam Frame
Kawasaki KR1 ? Aluminium Beam Frame
Aprilia RS125 Aluminium Beam Frame
Cagiva Mito Aluminium Beam Frame
Suzuki RGV150 Steel Perimeter frame
Suzuki RG150 (Quite heavy at 14.5kg standard frame and 5.5kg swingarm) Steel Beam Frame
Suzuki GSXR250 Steel or Aluminium Beam Frame Depending on year
Honda CBR250 ?
Yamaha FZR250 Steel or Aluminium Beam Frame Depending on year
Yamaha FZ250?
Kawasaki ZXR250 Aluminium Beam Frame

Donor Engines These engines are available for sale new without a bike. A good addition to a donor chassis.
Loncin CBD 150 (Modified Clone of Honda GL 145)
Loncin CBD 125 (Honda laydown stepthough clone)
Loncin CBD 110 (Honda laydown stepthough clone)
Loncin AX 100

[Dutchee]

Finally, when comparing the power developed by a two-stroke engine with that of a four-stroke of equal cylinder capacity, it must be appreciated that the actual working or swept volume of the two-stroke cylinder is only that which is contained above the top edge of the exhaust port.
Given a volumetric efficiency of 100% the cylinder of a four-stroke engine of 200 cc will contain 200 cubic cylinder of combustible mixture at the beginning of the compression stroke, but the compression of the mixture in a two-stroke cylinder cannot commence until the rising piston has closed the exhaust port.
This initial movement will occupy at least 25% of the stroke, so that even with 100% volumetric efficiency a 200 cc two-stroke engine must derive its power from only 150 cubic centimetres of mixture.
This fact is perhaps more readily appreciated when it is realised that in moving from the upper edge of the exhaust port to bottom dead centre and back again, the piston is performing the same function as the complicated valve gear of a four-stroke engine.
In order, therfore, to make a fair comparison, the performance of a 325 cc two-stroke for instance, must be set against that of a four-stroke engine which is the total volume of the cylinder, and the swept volume which is the volume of the cylinder above the exhaust port.
It is fortunate that organisers of motor-cycle competitions do not take this discrepancy of cylinder capacities into account for if this handicap were removed then two-stroke and four-stroke machines could compete on an equal footing.
~ The Two Stroke Engine - its Design and Tuning (K.G. Draper)

[TZ350]

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


....... but the compression of the mixture in a two-stroke cylinder cannot commence until the rising piston has closed the exhaust port.....

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

248246

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.

[husaberg]

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

I guess the fact that it fires twice as often and contains far fewer moving parts is a bit of an advantage to sometimes too.
The two stroke is a superior engine otherwise why would they keep changing the rules to try and make the four stroke more competitive Dave reckons Honda did it. I blame The Green party myself.
so oh well you wont be needing this then:bye:

shucks for old times sake and as i enjoy reading them anyway.

The last of the aprillia story to 95

To read them properly they have to be zoomed as well.

The book above the Dutchee quotes is the book i was talking to Koba about a couple of pages back.

I think the capacity of the ac 125 2 smokes and the 100cc LC 2 smokes vs the 155 ish 4 smokes is about ideal. Although the kt piston in a 100cc without the destroking would be perfect if you throw in open bearings as well.

[ac3_snow]

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

Got my engine running again tonight! And something I found quite interesting was testing the compression. 160 psi with no pipe, then added the expansion chamber and 165 psi! so the pipe definitely has the effect of pushing more air back into the cylinder (yea, captain obvious!).

Also have to add that the engine seems to rev alot quicker/snappier with the crank 'floating' (although this may be all in my head) should be even better when I finally get around to putting decent bearings in. - did find one bearing had previously 'spun' wearing out the crankcase housing, so hopefully a bit of locktite is enough to fix this :innocent:

I have a cooler plug for tomorrow (B9ES) bigger jet (was 130 main now 160) and will retard the timing a little so with any luck I can keep my piston whole.

[husaberg]

Got my engine running again tonight! And something I found quite interesting was testing the compression. 160 psi with no pipe, then added the expansion chamber and 165 psi! so the pipe definitely has the effect of pushing more air back into the cylinder (yea, captain obvious!).

Also have to add that the engine seems to rev alot quicker/snappier with the crank 'floating' (although this may be all in my head) should be even better when I finally get around to putting decent bearings in. - did find one bearing had previously 'spun' wearing out the crankcase housing, so hopefully a bit of locktite is enough to fix this :innocent:

I have a cooler plug for tomorrow (B9ES) bigger jet (was 130 main now 160) and will retard the timing a little so with any luck I can keep my piston whole.
Great to hear Snow
Wob mentioned above a 10 a couple of pages ago
Plus you never metioned the fuel Avgas?
Along this line

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.

[ac3_snow]

Wob mentioned above a 10
Plus you never metioned the fuel Avgas?

Yup race gas, and I had ordered the 9's before I read Wobbly's post unfortunately and didn't have time to get any 10's, my scientific plan is to.....

ummm.....


keep my fingers crossed.

[husaberg]

Yup race gas, and I had ordered the 9's before I read Wobbly's post unfortunately and didn't have time to get any 10's, my scientific plan is to.....
ummm.....
keep my fingers crossed.
Sorry not trying to put the wind up you, Just making sure you caught it.
9 is far better than 6 so you should be alright. You could always ask around at riders briefing?
I used to get away with NGK B9 EGV and it seemed to offer an improvement for me anyway over a std plug 9 plug HS?. Iridium plugs weren't around then. Well i never seen them.

I was reading an old article the other Day and it mentioned the TM 250 cdi offers static timing ie no advance or retard it was meant to be the hot ticket on a Suzuki TM125 race bike. Back in the Day.

[wobbly]

I think the analysis of the 2T working cycle when compared to the 4T in the example is a bit simplistic and missleading.
A full house 4T like say the Britten V1000 has a VE around 125% and an Ex duration of over 300*.
The 4T uses the exhaust tuning to create a depression during TDC overlap, giving the intake stream a chance to purge residuals out of the chamber.
In a 2T the Ex creates a depression around BDC, giving a Delivery Ratio of 1.25 ( same number effectively as the 4T ) and this purges residuals in the same way as the 4T.
BUT, the 2T uses the open Ex port in concert with the pipe design, to reverse the outflow,shoving clean, overscavenged clean Air/Fuel back into the cylinder, using a duration number closer to 200*.
The real kicker for the 2T is the huge efficiency gained by firing every revolution, doubling the Ex frequency, and thus the energy that can be used to good effect.

[speedpro]

I run a B8 or B9 on the kart track. It doesn't hurt with either. Big tracks I've always used a B9. On a kart track I don't think you are on the throttle enough to worry. If it blows up it's because the tuning is seriously screwed up.

[TZ350]

Finally, when comparing the power developed by a two-stroke engine with that of a four-stroke of equal cylinder capacity, it must be appreciated that the actual working or swept volume of the two-stroke cylinder is only that which is contained above the top edge of the exhaust port.
Given a volumetric efficiency of 100% the cylinder of a four-stroke engine of 200 cc will contain 200 cubic cylinder of combustible mixture at the beginning of the compression stroke, but the compression of the mixture in a two-stroke cylinder cannot commence until the rising piston has closed the exhaust port.
This initial movement will occupy at least 25% of the stroke, so that even with 100% volumetric efficiency a 200 cc two-stroke engine must derive its power from only 150 cubic centimetres of mixture.
This fact is perhaps more readily appreciated when it is realised that in moving from the upper edge of the exhaust port to bottom dead centre and back again, the piston is performing the same function as the complicated valve gear of a four-stroke engine.
In order, therfore, to make a fair comparison, the performance of a 325 cc two-stroke for instance, must be set against that of a four-stroke engine which is the total volume of the cylinder, and the swept volume which is the volume of the cylinder above the exhaust port.
It is fortunate that organisers of motor-cycle competitions do not take this discrepancy of cylinder capacities into account for if this handicap were removed then two-stroke and four-stroke machines could compete on an equal footing.
~ The Two Stroke Engine - its Design and Tuning (K.G. Draper)


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


....... but the compression of the mixture in a two-stroke cylinder cannot commence until the rising piston has closed the exhaust port.....

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

248246

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 think the analysis of the 2T working cycle when compared to the 4T in the example is a bit simplistic and missleading.
A full house 4T like say the Britten V1000 has a VE around 125% and an Ex duration of over 300*.
The 4T uses the exhaust tuning to create a depression during TDC overlap, giving the intake stream a chance to purge residuals out of the chamber.
In a 2T the Ex creates a depression around BDC, giving a Delivery Ratio of 1.25 ( same number effectively as the 4T ) and this purges residuals in the same way as the 4T.
BUT, the 2T uses the open Ex port in concert with the pipe design, to reverse the outflow,shoving clean, overscavenged clean Air/Fuel back into the cylinder, using a duration number closer to 200*.
The real kicker for the 2T is the huge efficiency gained by firing every revolution, doubling the Ex frequency, and thus the energy that can be used to good effect.

Thanks for expanding on that ........

[marsheng]

When you burn a fixed amount fuel and air you get an fixed amount of energy. So working backwards, the maximum BEMP of a 4 stroke is about 240 psi, 2 strokes are around 400 psi. If the volumetric efficiency of the 4 stroke is 100% then by that ratio, the VE of the 2 stroke is about 85% remembering that it has 2 strokes per cycle. (PS This ignores the extra friction of the 4 stroke engine. )

[wobbly]

It may be semantics but why "change" the calculation of bmep for a 2T by doubling
it because it fires every revolution.
The bmep of a full house 2T is around 200 psi, as this is a calculated relationship between measured torque and displacement.
The calculation is a measure of the ability to produce power PER CYCLE, divided by the number of power cycles.
Thus a 4T has a higher bmep capability, but is hamstrung by the halved number of available cycles.
This is an inherent advantage of a 2T, you cant just factor it away in the calculation.
And the VE numbers are simply a measure of the amount of air ingested per cycle divided by the displacement, and are essentially the same for full noise designs.

Its a bit like the people that go on about the measurement of power on a dyno.
The guys with huge Harley engines say that the power should be "corrected" for the big heavy pieces of shit when compared to a small screamer 125cc GP bike.
The reality is that the big , heavy pieces of shit are exactly that, and what is measured at the rear wheel, is the actual power delivered in the real world.The fact that they have huge flywheels that absorb "power" to spin up, is an inherent
part of the design, and in my opinion cant be ignored by applying some fudge factor that makes them feel better, about the Hp/cc figures.

[speedpro]

38.45?

We'll see

[wobbly]

Thats crank, should translate into around 34 rear wheel.
Same deal as getting 30 Hp was considered as impossible, for how many years - if everything is done properly there is no reason at all why the numbers cant be achieved.
Used to be that " the dyno dont lie", well now the same thing can be said of the Simulator.

[bucketracer]

38.45? ......

Whatt!!! we are still sniffing around 28 rwhp ourselves. I guess we will sooner or later find the upper limit of a 24mm carb, we have been to 30 but are not sure what the upper limit of a 24mm pumper kart carb is and may have to start looking at the plenum again.

[F5 Dave]

then if you can just re-engineer those annoying corners out of your track:innocent:

[bucketracer]

then if you can just re-engineer those annoying corners out of your track:innocent:

Yep ..... :bleh: ..... working on it.

[husaberg]

Whatt!!! we are still sniffing around 28 rwhp ourselves. I guess we will sooner or later find the upper limit of a 24mm carb, we have been to 30 but are not sure what the upper limit of a 24mm pumper kart carb is and may have to start looking at the plenum again.

Id like to the the carb where you have it in the Photo replaced with an air filter and then the carb placed in the std position with probably with a spacer plate to fit it in under the cover. That's my 3 cents.

Below is the crude rendering of what I was saying. Sorry about the carb being back to front don't try that at home.

[bucketracer]

Id like .... the carb placed in the std position with probably with a spacer plate to fit it in under the cover. That's my 3 cents.

Av's is setup that way, works well but she is happy with limited hp.

248309

That is a 34mm inlet tract inside the plenum, the simulation package says we need 34-36 or so for big hp.

The idea of the plenum is that the engine gets to suck fresh mixture from the plenum through a 34mm (or bigger) inlet tract while the plenum is refilled by the 24mm carb. This works at WOT because the 24 gets to flow all the time and the engine, because of inlet timing only gets to suck for half the time allowing the carb double extra time to keep the plenum full.

When TeeZee first thought of this idea, like most people he believed that it was the 24mm carb class rule that was the limiting factor keeping F4 125's running about 20rwhp.

As he pushed the power up past 20 on the way to 30, with each significant step, the plenum was tried and it made about the same as the conventional carb. We concluded from this that the conventionally mounted 24mm carb was not the real problem. It became apparent that the plenum was a clever solution to a problem that we didn't have yet.

The plenum with its extra complication may eventually have a place when we find the real limit of a conventional 24mm carb.

[husaberg]

Av's is setup that way, works well but she is happy with limited hp.

248309

That is a 34mm inlet tract inside the plenum, the simulation package says we need 34-36 or so for big hp.

The plenum with its extra complication may eventually have a place when we find the real limit of a conventional 24mm carb.

30 hp is big HP, Isn't it.
I understand the Idea behind it (the Plenum) But have you tried the set up AV has along with tz's engine spec.
As I guess the rest of AV's engine could be the limiting factor. Just a thought.


I also believe there could by a case to be made for not having all the air flowing through the carb.
To do this by way of a supplementary air intake and the mixture flowed through the 24mm carb richened say by a electric controlled power jet to compensate or fuel injector.
kind of like how some modded turbo cars used to bypass the restrictive airflow meter if you catch my drift. Easy for me to say. No doubt harder to do I suppose.

Here is the old CanAm way of tucking in a carb on a old Disk valve Rotax engine. A bit long for high revs probably.

PS the Rotax was 6 speed in 125 form and is not legal I checked.The road legal version was still listed as a Enduro model.

Or just chuck on a big ol Harley flat filter. I hear the chicks dig harleys. Most of them are nearly 30
IQ/Stone for the chicks HP for the Harley's

[bucketracer]

248325


Here is the old CanAm way of tucking in a carb on a old Disk valve Rotax engine. A bit long for high revs probably.

248326


In trying to get the carb tucked in, it has realy upset the curve.

248324


Red line is the sticking out the side carb arrangement, Blue line is the tucked out of the way arrangement.

The carb made good power when stuck on the side conventionally but lost power when tucked out of the way, I expect the result would have been the same for the CanAm

[husaberg]

The carb made good power when stuck on the side conventionally but lost power when tucked out of the way, I expect the result would have been the same for the CanAm

Yes and No

The Cam am was the class leader for its time for both spread of power and for outright HP. This was achieved I believe in spite of its layout, rather than because of it. It certainly wasn't a revver around 8000rpm Whoops (9000 rpm actually EX spread though it was a bit of a revver) I think? (will check and Edit later) Later Well revs better than I thought. Don't get to excited by the HP as it is the 250 but it was the best they had ever ran a 250mx bike in 73 and had the best spread of power too. (Only a 32mm carb as well which would be the EQ of a 20mm carb on a 125)

But we digress
I put a pic in to show the lay out only hence the tag with it. What about the other bit. A workable solution or what.(assuming I don't have to do the work that is)

30 hp is big HP, Isn't it.
I understand the Idea behind it (the Plenum) But have you tried the set up AV has along with tz's engine spec.
As I guess the rest of AV's engine could be the limiting factor. Just a thought.


I also believe there could by a case to be made for not having all the air flowing through the carb.
To do this by way of a supplementary air intake and the mixture flowed through the 24mm carb richened say by a electric controlled power jet to compensate or fuel injector.
kind of like how some modded turbo cars used to bypass the restrictive airflow meter if you catch my drift. Easy for me to say. No doubt harder to do I suppose.

[Frits Overmars]

..........

[Frits Overmars]

...The idea of the plenum is that the engine gets to suck fresh mixture from the plenum through a 34mm (or bigger) inlet tract while the plenum is refilled by the 24mm carb. This works at WOT because the 24 gets to flow all the time and the engine, because of inlet timing only gets to suck for half the time allowing the carb double extra time to keep the plenum full.Way to go, Bucketracer. But there's one thing to consider: unless the tract from plenum to engine starts at the deepest point of the plenum, a puddle of fuel will form in the plenum which will make setting the carburation a nightmare. I've been there....


...I guess we will sooner or later find the upper limit of a 24mm carb, we have been to 30 but are not sure what the upper limit of a 24mm pumper kart carb is and may have to start looking at the plenum again.If you manage to get a really continuous flow through that 24 mm hole, the limit should be about 60 HP, give or take. No, I'm dead serious.
(I'm just talking about the carb though; not about its combination with a bucket engine).

[Buckets4Me]

Way to go, Bucketracer. But there's one thing to consider: unless the tract from plenum to engine starts at the deepest point of the plenum, a puddle of fuel will form in the plenum which will make setting the carburation a nightmare. I've been there....



snap. TZ did get it to run around the track but it did have problems with rear wheel grip (wet track and running the oval on slicks)

[wobbly]

WooHoo, we have the esteemed Mr Overmars poking around in here, better be very careful in what I say, he has hawkeyes for the slightest mound of bullshit.

As I have said before the 24mm carb is a long way from being the final restriction in the bucket engine - we have regularly seen 46 Hp from a Maxter 125 kart engine with a 30mm carb on the front, its the ports and pipe that need serious attention.
The poxy old RS125 pipe hanging off that 28Hp engine is miles away from being optimum.

[Frits Overmars]

WooHoo, we have the esteemed Mr Overmars poking around in here, better be very careful in what I say, he has hawkeyes for the slightest mound of bullshit.It's a bit late to start being careful now, Wob :devil2:. I am a fairly regular reader here; I just refrained from writing, for lack of time; you know how it is with forums.
But Bucketracers remark about continuous flow via a plenum was too good not to react.

Now what could be the next step? Moving the plenum volume to the other side of the inlet disk?
An enlarged crankcase volume would lower the resonance frequency of the inlet system and you would need to correct this, for instance by drastically lengthening the inlet timing.
See where this is going? You tell them, Wob; while you guys are having breakfast, it's time for me to get some sleep.

[richban]

WooHoo, we have the esteemed Mr Overmars poking around in here, better be very careful in what I say, he has hawkeyes for the slightest mound of bullshit.


Not Fare. I'm emailing Prof Blair. We may now need to rename bucket racing to F1.

[Frits Overmars]

Beginner's question: how do you delete a post?

[koba]

Beginner's question: how do you delete a post?

Click "Edit Post" and there is a check-box for delete.

EDIT: It's changed since I last did it, it is now a button.

[Frits Overmars]

Click "Edit Post" and there is a check-box for delete.
EDIT: It's changed since I last did it, it is now a button.Thanks Koba, but I must be getting too old for this; I still can't find it. Could you indicate this button in a screenshot?

[wobbly]

The case vol is already pretty big in that engine ( under 1.3) - but my hazy memory seems to say that the inlet timing was pretty conservative, and wasnt changed when the case vol went up.
Current thinking in a road race setup would indicate 145/90 is the outer limits of whats needed so this could be tried, opening up one side at a time.

[koba]

Two steps.

The first button only shows on your own posts.
Once they get past a certain age I don't think they can be deleted or edited.

A moderator can delete anything, I think.

[Yow Ling]

Hey Frits welcome to New Zealand, great to see another Dutchman on the forum !!

[husaberg]

Attached is a copy of two articles on the Honda nsr500 water injection system trailed once.
I believe as spelled out by Wobbly who was there, At the meeting where Doohan tried it and as he could only say, it was crap. Then dumped.

I got a little flack (Well quite a lot actually) last time I brought it up.Then kel posted an brief article surrounding it. that did seem to suggest it was crap indeed.

The problem Wob mentioned was that although it worked to increase low end power it was too slow in reheating the pipe after use so it either didn't work or it killed the top end. Fair call.
I believe it still has merit. Why assuming the engine is developed with a ignition optimised and power valve system optimized.
As well as porting. It is one of the few areas left to improve low and mid range power. By 24%
Now I had seen an articles and I always assumed like, I guess everyone else.

That Honda injected water into the pipe.
Well, it would seem. they did not.
Why else would they have a radiator for the water injection system?
Also why does the pipe look like a water jacket?

I believe it was a water cooled pipe only. The article below should (hopefully) back this up.
After the pipe is cooled by the water injection. To heat the pipe I envisage using the system Honda have used a system along with other manufacturers on four strokes (Bikes and cars) that inject air into the pipe to lower emissions. A by product of this reaction is the unburnt fuel left in the exhaust is burnt thus creating heat.
The system I envisage is a true water injection into a header pipe powered by compressed air from a cylinder controlled by a solenoid triggered by the ignition at low throttle openings and revs for a 24% power increase as specified by Flecks experiments. The pipe can then be reheated an instant after the throttle and the revs indicate full power top end power is required by adding fresh air to the pipe (hopefully Stainless) Well that's my theory. Below is Kels article and the one I found.

There is a long YouTube story Honda's water injection But it is alas in Italian.
I would love to understand what is says.
I would also love to see a copy of the fleck SAE papers relating to water injection.

http://www.youtube.com/watch?v=ousgsIbW7WY
http://homepage.mac.com/rg500delta/Delta/Delta4.htm#Waterinjection
http://www.suzuki-rg500.com/water.htm
http://http://homepage.mac.com/rg500delta/Delta/image/water.jpg (http://homepage.mac.com/rg500delta/Delta/image/water.jpg)

I have also contrived. (What i think at least) Is cunning way to seal and operate a variable pipe length to further increase top end power to run in conjunction with this.

[k14]

Click "Edit Post" and there is a check-box for delete.

EDIT: It's changed since I last did it, it is now a button.
It might be possible that you need a certain number of posts before you can delete one. Best to ask a mod if he can't see a button to do it.

[sonic_v]

Not Fare. I'm emailing Prof Blair. We may now need to rename bucket racing to F1.

You might get more joy if you held a séance.

[ac3_snow]

Sunday was a great day racing at Mt Wellington. Beautiful weather, good people, just needed my own bike!

Ended up racing a FXR again (becoming a bit much of a regular occurrence unfortunately). I got my bike out on the track for the first practice round....then blew the head off. Came back in and it was sitting loose, o-ring/head-gasket blown to bits and two of the head studs had started ripping the thread out of the barrel. For a while I thought the cause may have simply been my dodgy compression measurements giving my higher than 14.66:1 but, I only had 165psi which to me is not enough to pull the studs out. Anyway will have to helicoil them and try again.
Speedpro suggested I may have got a bit carried away tightening them and weakened the thread, quite possible that my tourqewrench (read: right hand and powerbar) wasn't calibrated correctly:innocent:

[2T Institute]

Hey Frits nice to see you imparting your wisdom here.

Just cracked open a Rotax 256 had 155/90 as the disc timing.........:) kart blokes bless em all :)

[F5 Dave]

. . . o-ring/head-gasket blown to bits and two of the head studs had started ripping the thread out of the barrel. For a while I thought the cause may have simply been my dodgy compression measurements giving my higher than 14.66:1 but, I only had 165psi which to me is not enough to pull the studs out. Anyway will have to helicoil them and try again.
Speedpro suggested I may have got a bit carried away tightening them and weakened the thread, quite possible that my tourqewrench (read: right hand and powerbar) wasn't calibrated correctly:innocent:
You young lads & your over developed right arms:innocent:
presumably you have rechecked your squish in several positions? Is it possible the head isn't central & the piston smacked the side of the head when running?

[Buckets4Me]

Is it possible the head isn't central & the piston smacked the side of the head when running?

That was talked about at the track
but there was no obvios signs of the piston hitting the head

[bucketracer]

When you burn a fixed amount fuel and air you get an fixed amount of energy.

BMEP the gauge that allows the serious engine developer a direct way to compare different internal combustion engines, from lawn mower to massive prime movers.

2-T BMEP (psi) = HP x 6,500 / L x RPM

4-T BMEP (psi) = HP x 13,000 / L x RPM

where L = Liter and converting PSI to Bar is Bar = PSI x 0.069


That is your Google search, internet based assessment ....... Many is the spotty little kid fresh from his education, that soon realises the difference between the theory and experience is massive...... I am suitably qualified to .....

Arrr … yess … :scratch:… I did a Google search before posting these handy formulas too ……..

SS, I am lucky your so well qualified, because you could help me with some of that real world industry experiance of yours and flesh out the BMEP concept a bit as I am particularly interested in the how the idea was developed and the way the BMEP formula itself was derived.

I could research it some more on the net, but hearing it straight from the experienced developer in his own words would be so much more real and insightful, for sure.

[speedpro]

. . . . I could research it some more on the net, but hearing it straight from the experienced developer in his own words would be so much more real and insightful, for sure.

Sarcastic little whipper-snipper isn't he :killingme:killingme

[bucketracer]

248512

I think Husanberg is right about about the NSR water injection not actually being water injected into the pipe but a cooling muff around the header pipe and that the thermal capacity of the muff and its water may be what delayed the pipe getting back up to temperature again.

248510 "Water injection radiator", injection?? Husanberg told me how he thought it worked and it looks more likely that hot water vapor is being cooled again after water was circulated, possibly by an air blast around the header and then flashed off as steam.

The text talks about a radiator for cooling the exhaust water injection circuit, the word injection may have misled us.

I think the word "injection" shouldn't have been there and it should have read something like" the radiator is a condensor, cooling the exhaust water/steam circuit", a big difference.

248511 The expansion chamber header cooling muff. My hats off to Husanberg for spotting this and giving me the heads up.

I think TeeZee will be very interested in all of this as it looks like traditional water injection into the header might be back on the menu.

[wobbly]

Ahha, I see where things were getting out of whack with the bmep numbers.
Take the very best 125GP engine specs and plug that into the formula.
We have 50Hp times 6500 divided by 0.125 times 13000 = 200psi which is a real, usable number, I see all the time.
Use the same numbers for a 4T and we have 50 times 13000 divided by 0.125 times 13000 = 400psi , that is completely impossible, and this is the whole reason a 2T is superior to a 4T when compared apples for apples.

I was getting lost with the difference between VE and DR.
DR is actual air ingested divided by swept vol, and in a racing 2T gets up to around 1.25.
VE is basically the same but factors in the other term of TE ( trapping efficiency) that indicates how well the engine retains the air it has ingested.
Due to short circuiting, VE is always lower than the DR - my mistake.

[husaberg]

Ahha, I see where things were getting out of whack with the bmep numbers.
Take the very best 125GP engine specs and plug that into the formula.
We have 50Hp times 6500 divided by 0.125 times 13000 = 200psi which is a real, usable number, I see all the time.
Use the same numbers for a 4T and we have 50 times 13000 divided by 0.125 times 13000 = 400psi , that is completely impossible, and this is the whole reason a 2T is superior to a 4T when compared apples for apples.

I was getting lost with the difference between VE and DR.
DR is actual air ingested divided by swept vol, and in a racing 2T gets up to around 1.25.
VE is basically the same but factors in the other term of TE ( trapping efficiency) that indicates how well the engine retains the air it has ingested.
Due to short circuiting, VE is always lower than the DR - my mistake.

Unless we include a turbo or Blower into the equation I guess? 530psi turbo f1 era
We haven't got far considering Norton was around 200psi with the Manx (Works specials) in 1955.

Any ideas how to get a hold of Jerry Burgess to ask about the water injection or water cooled Header?
Your theory on how it worked from memory is a injection into jacket then flashover to steam maybe?

[TZ350]

From http://www.epi-eng.com/piston_engine_technology/bmep_performance_yardstick.htm

"At the end of the 2006 season, most of these F1 engines ran up to 20,000 RPM in a race, and made in the vicinity of 750 HP. One engine for which I have the figures made 755 BHP at an astonishing 19,250 RPM. At a peak power of 755 HP, the torque is 206 lb-ft and peak-power BMEP would be 212 psi. (14.63 bar). Peak torque of 214 lb-ft occurred at 17,000 RPM for a BMEP of 220 psi (15.18 bar). There can be no argument that 212 psi at 19,250 RPM is truly amazing."

It looks like 220psi is about it for a naturally aspirated race 4-Stroke, by comparison a Lycoming aircraft engine has a BMEP of about 163psi. There are only two ways to increase power, increase Torqe (BMEP) and/or RPM. BMEP tends to fall off as RPM is increased, so to increase BMEP and RPM is quite a feat, it usually becomes a trade off.

After playing with the numbers.

A 35 crank hp, 140 PSI BMEP 13,000 rpm 2 stroke 125cc F4 bucket engine looks within realistic reach and has plenty of development potential.

If a 150cc FXR could be developed up to FI car racing spec giving 220 psi BMEP and spun to 13,000 rpm then the power at the crank would be 33hp for about 30 rwhp.

A 25-27 rwhp FXR is achievable with the upper limit for F4 150cc 4-T's close to 30 rwhp.

So Rich's bike is possible and might not be just a rumor after all..... :facepalm:

[husaberg]

After playing with the numbers.

A 35 crank hp, 140 PSI BMEP 13,000 rpm 2 stroke 125cc F4 bucket engine looks within reach.

And by some skilled effort a 150cc FXR could be developed up to FI car racing spec giving 220 psi BMEP and spun to 13,000 rpm then the power at the crank achievable would be 33hp for about 30 rwhp.

A 25-27 rwhp FXR looks achievable with the upper limit for F4 150cc 4-T's at about 30 rwhp.

So Rich's bike is possible and might not be just a rumor after all..... :facepalm:

I did some quick math ages ago and came up with 40-44 BHP for a 100cc supercharged 22 psi inter-cooled water injected 8 valve twin 4 stroke with a Asian 300 at 1/2 engine speed. $ and kgs though.6.5:1 comp ratio Gates Mitzi evo balance shaft belt was the idea.
30 BHP is a more realistic target though. With a monster power spread.
Not sure What Speedpros estimate was? The catch is it really needs to be a twin.

[TZ350]

I did some quick math ages ago and came up with 40-44 BHP for a 100cc supercharged 22 psi inter-cooled water injected 8 valve twin 4 stroke. $ and kgs though.
30 BHP is a more realistic target though. With a monster power spread.

Now that interest me, we have a few 100cc 4-T engines about the place...... :shifty:

I played with a few supercharged engines when I was engine reconditioning (Automotive Machinist), unlike turbos they had super wide power bands with no "turbo lag". You didn't have to do much in the way of port and polish, more strengthening and cooling, std cam worked well too, but the valve train needed to be setup well and the ignition and compression had to be knocked back a mile, and the noise!!!, the only thing that drowned the exhaust out was the shreek of the belts and the sound of the tyres scrabbling for traction. Used to mark the manifold pressure gauge and when the boost pressure started to fall off when caning it, you knew you were starting to burn an exhaust valve or had bent one.

I just love supercharged engines....

[wobbly]

Yea, but no one has even approached the ultimate 100cc reed, with over 34RWHp, a spread from 8000 to 14000 in a chassis that weighs nothing and actually handles.
This combination is easily achievable, with well known technology, that doesn't involve anything more than some good hardware ,a die grinder, some CNC work with heads and exhaust nozzles, and a couple of days running pipe sims.
Bloody simple comparable to the head, cam,injection and turbo work needed to get the 4T even remotely close.

[TZ350]

Yes, it dosent look like a 150cc F4 4-Stroke can be pushed past 30 rwhp but a stroker has much more easily realised potential.

How is that special engine for Yowling coming on? any more photos? ....... :drool:

[Buckets4Me]

you knew you were starting to burn an exhaust valve or had bent one.

.

and what did you do when you bent a valve ?

[TZ350]

and what did you do when you bent a valve ?

said ... Ohhh gosh darn........ true .... :innocent:

Nope I stuck em in a lathe and tapped them true again......... there, the secret is out.

If they had become too bent to be able to straighten again you didn't need a boost gauge to tell you, you had a problem.

[kel]

Now what could be the next step? Moving the plenum volume to the other side of the inlet disk?
An enlarged crankcase volume would lower the resonance frequency of the inlet system and you would need to correct this, for instance by drastically lengthening the inlet timing.
See where this is going? You tell them, Wob; while you guys are having breakfast, it's time for me to get some sleep.

Frits, its a real pleasure to have you contributing to this thread:)
I hope you'll forgive me for being so presumptuous but could you take a moment to introduce yourself so as the regulars here can understand just how privileged we are to have you contributing.
I will have a stab at formulating an answer to what you have outlined above but you must forgive my errors as I have no notes or books to reference at the moment plus the crankcase remains a mystery to me at the best of times (variable flask, Helmholtz and all) but here goes - The increasing of the crankcase volume will alter the point at which we would close the inlet as the case pressure will reverse the flow through the carburetor latter in the cycle. The potential problem I would guess here is that rotary inlet has little inlet inertia, apparently pulse tuning in a rotary inlet is a no go?
For the opening point the crankcase balancing could take place latter but Im guessing we should open the inlet as early as possible and let the expansion chamber work its magic, but how early, the transfer flow would still need to bring down the case pressure before opening the inlet.
So just how far out am I?

[husaberg]

Yea, but no one has even approached the ultimate 100cc reed, with over 34RWHp, a spread from 8000 to 14000 in a chassis that weighs nothing and actually handles.
This combination is easily achievable, with well known technology, that doesn't involve anything more than some good hardware ,a die grinder, some CNC work with heads and exhaust nozzles, and a couple of days running pipe sims.
Bloody simple

I like the sound of this Wob as you already know. Although I thought it was 35HP.
Have you got any further with the Mike (Yow ling) engine?

Any Ideas on how to get more info Re the Honda Water injection. Like Say Jerry. The Net is coming up empty for me. I'd also love to see a copy of the SAE papers relating to it (Fleck)

[wobbly]

Yow Lings engine build has stalled as it needs a new crank web due to severe damage I found when I pulled it apart to install the stuffers.

I have Pete Bensons contact details, he was the kiwi head spanner man at Honda under Burgess, so I will see if I can contact him when he is in Philip Island this weekend, or when he comes home afterwards.

Wave tuning on a Rotary inlet system can be achieved in theory,using the 3rd harmonic as is done in reed engines, but in a practical application we have to run the carb/inlet length as short as is physically possible.
This puts the waves strongest action above the forcing frequency of the engine, because if you "tune" it correctly, the action is so strong and abrupt, the carburation becomes impossible to adjust in this narrow band,as evidenced
by huge amounts of standoff created by the same air passing the main jet several times.
You could tune the length below the powerband, but then the carbs hit the ground before the riders knee does, or in the case of a RSW, the bellmouth is in the middle of the rear shock spring.

[husaberg]

Yow Lings engine build has stalled as it needs a new crank web due to severe damage I found when I pulled it apart to install the stuffers.

I have Pete Bensons contact details, he was the kiwi head spanner man at Honda under Burgess, so I will see if I can contact him when he is in Philip Island this weekend, or when he comes home afterwards.

Wave tuning on a Rotary inlet system can be achieved in theory,using the 3rd harmonic as is done in reed engines, but in a practical application we have to run the carb/inlet length as short as is physically possible.This puts the waves strongest action above the forcing frequency of the engine, because if you "tune" it correctly, the action is so strong and abrupt, the carburation becomes impossible to adjust in this narrow band,as evidenced
by huge amounts of standoff created by the same air passing the main jet several times.

Thanks Wob
You have to wonder about the percentage of Kiwis and Aussies involved in GP and F1. We must box well above our weight in that regards.Cheers
The pulse wave I would have thought would be very strong in a Disk Valve
With its positive abrupt closing and opening.
I would have thought the reed would damp out the pulse a bit. Just an observation based on an assumption from 2 vs 4 exhaust tuning intake and exhaust theory.
I guess the cons would out weight the pros of using this as the fueling, I believe is more problematic on a disk as it is without over complicating it with pulse tuning as well.
I have noticed that whenever the GP500 V4's engines were redesigned the intakes always became shorter and more even in length. Most of the time they did this to the determent to engine balance (layout). So they were doing it for performance and I suppose layout for chassis design weight distribution as well to a degree in hindsight.

Anyone considered or played with offset cylinders such as in Yamaha R1 and YZF450 would that give us slightly (ever so slight) asymmetrical port timing? (Don't flame me has I having done the Math yet its just a hunch.)
As well as a bit of extra leverage at TDC?

Non-symmetrical timing is only possible with controlled valves (e.g. for the carburetor inlet via a window in the crankshaft or on a four stroke engine) or when the cylinder is offset from the axis of symmetry
• the cylinder shaft (con-rod) and crankshaft are offset. What this means is that the cylinder is not directly vertically overhead of the crankshaft. It is offset to a small degree, to one side of the crankshaft. So when the piston is at TDC, the conrod is not at an exactly vertical position but is already slightly slanted. When the air-fuel mixture burns, the power stroke now has a better 'leverage' on the crankshaft and this helps to extract more power out of the combustion.

Below the Swissauto and sometimes BRM later the ROC later on known as the pulse?
If you look at the bottom of the 3rd page at the lower of the 3 pictures. You will be able to see what Wob and I were talking about with mikes (RGV100) crankcase mods being reminiscent of the Swissauto.
Note the Weight 36kg with airbox and carbs and oil.

[TZ350]

If you manage to get a really continuous flow through that 24 mm hole, the limit should be about 60 HP, give or take. No, I'm dead serious.(I'm just talking about the carb though; not about its combination with a bucket engine).

Thats very interesting to know, if we find the 24mm carb restriction is starting to hold us back the plenum may yet come out of Buckets closest again.

At the moment blow-down-time-area is holding us up, also an optimized pipe design would be nice too.

248655 248657

34mm at the valve and 24mm carb


Way to go, Bucketracer. But there's one thing to consider: unless the tract from plenum to engine starts at the deepest point of the plenum, a puddle of fuel will form in the plenum which will make setting the carburation a nightmare. I've been there....

Yes that was the Team ESE experience......

We even tried pumping the puddled fuel back to the tank.

The 34mm engine/plenum inlet was initially very short and there was a resonance problem at about 4-5,000 rpm, the standoff or spit out of the carb extended to the front axel.

248656

This was greatly reduced by lengthening the engine/plenum inlet.

248658 248659

The current thoughts are, if we try the plenum again it will be with a short inlet and the VeTec inlet butterfly thing for changing the inlet resonance.

248654

Or a variable crankcase volume with a butterfly arrangement that opens an extra side chamber attached to the crank case volume.

Frits I would be interested in your opinion about the usefulness of some sort of variable crankcase volume.

[Kickaha]

Below the Swissauto and sometimes BRM later the ROC later on known as the pulse?
If you look at the bottom of the 3rd page at the lower of the 3 pictures. You will be able to see what Wob and I were talking about with mikes (RGV100) crankcase mods being reminiscent of the Swissauto.
Note the Weight 36kg with airbox and carbs and oil.

Ta for that, always wondered how it was positioned in the sidecar

The sidecar I passenger on would have originally had one of them lovely two stroke thingys in it although more likely Krauser/ADM

[Kickaha]

Couldn't find a Swissauto but here's the Krauser
<iframe width="420" height="315" src="http://www.youtube.com/embed/rs_YRWe_8wo" frameborder="0" allowfullscreen></iframe>

[Buckets4Me]

E.S.E Factory rider takes a spill (need to stop her racing in the lesser classes)

248624 "
Avalon Biddle (http://www.facebook.com/avalon.biddle)
Not racing today after bike seized in practise yesterday and flicked me off so didnt go out in qualifying. Sorry guys :( "

[TZ350]

248728

A seizure, that's bad luck Av, after all your effort to get there.

[TZ350]

.
I have been doing a bit of dyno work with Bucket to find out what inlet layout is the best for our Suzuki GP125 engine and 24mm carb.

We know that on a 4-stroke the best inlet shape starts larger and tapers down increasing the gas velocity to a maximum just before the valve.

248689

The question is, what is the best shape for a 2 smoker?

Should the 2-stroke inlet taper down like the 4-stroke, go straight or diverge at 1 deg or maybe 14-15 degrees.

248690

Whats best, stay the same 24mm carb to 24 at the rotary valve which is pretty much the standard Suzuki GP125 setup.

248733

Or taper out from the 24mm carb to something bigger at the rotary valve, and should it diverge by 1 deg or much more.

248691

Or very little taper, going quickly from 24mm carb out to the 32mm inlet and then finishing as 34mm at the rotary valve.

If the carb rules were open this probably wouldn't be much of a problem but being restricted by our racing class rules to a 24mm carb, and for our BMEP/RPM target the simulation software specifies a 36mm carb equivilent port size at the rotary valve. So the shape of the inlet tract has become an issue and we have been putting in some dyno time to find out what works best for us.

Also Bucket has come up with an imaginative way of having a variable crankcase volume (CCR) and inlet tract.

[husaberg]

.
I have been doing a bit of dyno work with Bucket to find out what inlet layout is the best for our Suzuki GP125 engine and 24mm carb.

We know that on a 4-stroke the best inlet shape starts larger and tapers down increasing the gas velocity to a maximum just before the valve.



I have no idea about the ports,
but what does strike me as being interesting is that compared to the aprillia/Rotax disk valve 125 pic I posted a while back.
Your crank wheels would seem to to be more in the way of the incoming charge.
I will post the pic for comparison.
Of course this could be because the pic is an old one before you machined them to a smaller diameter? Just a thought.

I bet the Aprilia is a much larger diameter disk valve.
So it is open wider for greater percentage of the time/area than comparable timing would have a smaller disk.If that makes sense.


Also with your valve covers can these be shortened to use with the pumper carb.
Even if it ends up being (the Pumper carb) bolted direct to the cover on an angle if necessary to avoid the spline just a thought I suppose the primary gear and the clutch cover is in the way. Shame its on that side.Is there any way to modify it to shorten it more?

Found this on the Web I wonder what happens when they get fuel soaked.

http://www.bsagoldstar.co.uk/about/about.htm


Phil's first motorcycle was a BSA Bantam Major which was soon replaced with a 250cc Ariel Arrow Super Sports. Phil tuned this by putting balsa wood in the balance holes of the flywheels to increase crankcase compression. Innovative idea mustn't have had any Cork?:shit:paint them i guess?

[TZ350]

..... but what strikes me as being interesting is that compared to the aprillia/Rotax disk valve 125 pic I posted a while back. Your crank wheels would seem to to be more in the way of the incoming charge. I will post the pic for comparison. Of course this could be because the pic is an old one before you machined them to a smaller diameter?

I would be interested in seeing the photo for comparison. A std the Suzuki is flat faced, I had the inlet face machined back at 45 deg and built the floor of the inlet port up with Devcon. It is an old photo. Later the balance holes were plugged and the wheels were reduced 2mm overall to increase the case clearance.

The plugs reduced the BF below 50% so I had to get a bit aggressive with the drill press to get back to the 50-55% range that seems to suit my bike.

[TZ350]

The system Bucket and I tried for pumping the fuel that would pool at the bottom of the plenum back to the tank. The plexi glass was something I think Kick suggested so we could see what was happening inside. We were also going to try a straight shot from the side but then things were getting far to wide.

[F5 Dave]

But it didn't work did it? that pump won't be self priming & as soon as you suck air, which you will regularly, it will stop working.

but I can't think if a clever way to do it, unless you just had a low level drain tank with a one way valve.

[TZ350]

but I can't think if a clever way to do it, unless you just had a low level drain tank with a one way valve.

Tried the low level drain tank idea but there was too much fuel.


But it didn't work did it? that pump won't be self priming & as soon as you suck air, which you will regularly, it will stop working.

No No worked very well as a scavenge pump, its a case pulse pumper and re-primed itself easily, like cart pumper carbs will, as long as the diaphragm flapper valves are wet with oil/fuel .......

The FZR 3LN tank has a handy tank air breather on the bottom that I was able to plug onto, the breather exits above fuel level inside the tank. But like you say, it sucked a lot of air, enough to pump the tank up, even with a 3mm breather hole drilled through the filler cap. You could see the tank expand. It also frothed the fuel going back into the tank.

Also the fuel frothing in the tank probably wasn't helped by a bad crank vibration problem I had at the time. The vibration was OK at 10-11 where I was making power before, but became severely crap at 13, but with the crank re balanced to a 52% BF the vibration at 13 is much better now.

As the scavenged fuel had a very high percentage of oil in it, I started to wonder how much oil was actually going to the engine. Although I had touched 30rwhp I was starting to feel very uncomfortable sitting on a bike that was jumping around at 13,000 rpm like a demented jack rabbit, spilling fuel out of the filler cap, wetting me, the bike, hot exhaust and dyno.

If I go there again I will try a sump like you suggest with a much smaller pump, like something fashioned from a small weed eater carb. Or use the tank pressure from this one for feeding the kart carb. Husaberg has talked before about pressurizing the tank to get good fuel flow through the Tillotson carb.

[F5 Dave]

well I stand corrected about the pump. Would have thought that little thing would have not been able to get the fuel up that head.

It appears you were right & I was, perhaps a little less right than you were.

But the 'take home message' from this was that I was right.:shifty:

Glad we cleared that up.:innocent:

[TZ350]

Yes the pumps ability took me by surprise too and yes your right about the other thing also ... :shifty: ...

[Gigglebutton]

the diaphragm flapper valves are wet with oil
I started to wonder how much oil was actually going in Although I had touched 30 I was starting to feel very uncomfortable sitting on that jumping around at 13,000 rpm like a demented jack rabbit

A bit homo erotic for a public forum guys :innocent:

[husaberg]

Your welcome to nominate a dyno of your choice and have a friend come along with a video camera ... and of course you get to cover the dyno time, same rule for all ....... :laugh:
I know Dave loves boost bottles. :shit:

Pah! What a load of bollocks (no offense I mean the bolt on goodies merchants website). I love these descriptions of what is supposed to be happening & how it will cure the common cold etc.

Yamaha made these famous in the 80s on their MX bikes. But there is a reason you don't see them on modern high performance bikes. (well infact the RG150 has one, but in the form of a long rubber tube). They are really only useful as a plaster for a badly designed (or rather mismatched) pipe. TSR software will tell you how to design one for the area you are trying to affect.






So this is partially for him.
Could this be a place for one. It could even be of varying volume? possibly.
This could be accomplished with a diaphragm. Much like a pressure vessel on a Water pump you could even plumb it with a butterfly valve.
Could this be a create an effective Plenum chamber? Down steam from the carb.
Also a variable factor to crankcase volume? Musing aloud here. A lot of could's and Ifs but..............


. Husaberg has talked before about pressurizing the tank to get good fuel flow through the Tillotson carb.

Only regurgitating Jennings? I think? Was that the Bridgestone 350 with mcCulloch carbs stuff? No original ideas from me sorry.:innocent:

[wobbly]

I have tested "boost bottles" between the carb and the reed.
They improve throttle response very low down in the revs off the pipe.
A couple of older quads used the idea, and one will hardly run at all off the bottom end if the bottle is removed.
But compared to a ATAC on the header they are virtually useless for improving power at the bottom of the useable band.
Whereas the wave/pressure action in the pipe is so much stronger that a flapper valve controlled chamber on the BSL500 gave 28% more power at around 7000 - was closed by 8000 and had virtually no effect at that rpm and up.

[F5 Dave]

Husi seems to love saying what I love??? Mostly its all news to me.:mellow:

My impression is that Boost bottles are generally a bandaid for a poorly designed pipe. I built a variable volume one for my old H when I poorly designed a pipe with too much baffle angle & I couldn't be arsed fixing it. It smoothed out the dip before peak power & was fun to play with for a laugh & easier to change than the pipe which was a long twist up around swing arm type.

[husaberg]

Husi seems to love saying what I love??? Mostly its all news to me.:mellow:

Relax Dave Husey enjoys quoting you, only because you are always so quotable.
This is what you actually said in full. Apologies if you do indeed have no opinion on them. My jibe was in jest. Sarcasm is indeed wasted on the goof.

http://http://www.sip-scootershop.com/EN/Products/11701000/Boost+bottle+POLINI.aspx (http://www.sip-scootershop.com/EN/Products/11701000/Boost+bottle+POLINI.aspx)


Pah! What a load of bollocks (no offense I mean the bolt on goodies merchants website). I love these descriptions of what is supposed to be happening & how it will cure the common cold etc.

Yamaha made these famous in the 80s on their MX bikes. But there is a reason you don't see them on modern high performance bikes. (well infact the RG150 has one, but in the form of a long rubber tube). They are really only useful as a plaster for a badly designed (or rather mismatched) pipe. TSR software will tell you how to design one for the area you are trying to affect.






I have tested "boost bottles" between the carb and the reed.
They improve throttle response very low down in the revs off the pipe.
A couple of older quads used the idea, and one will hardly run at all off the bottom end if the bottle is removed.
But compared to a ATAC on the header they are virtually useless for improving power at the bottom of the useable band.
Whereas the wave/pressure action in the pipe is so much stronger that a flapper valve controlled chamber on the BSL500 gave 28% more power at around 7000 - was closed by 8000 and had virtually no effect at that rpm and up.

Have anyone ever seen one used on a rotary valve?
I can't recall ever seeing one ever mentioned on a rotary valve? (There way be an obvious reason for this I am overlooking)(Tell you the truth I have never got my head around the reeds on the KR250 either)
I thought it might work and if it had a diaphragm the volume could be easily adjusted for trials on the dyno IE by either putting a vacuum or pressure on it to adjust volume.
I guess it might pulse a bit too with the pressure in the intake too? I dont know if that would be good or not.
Obviously the diaphragm would have to be mounted towards the middle a bit of the "Boost bottle".
It could solve the over metering and fuel drop out puddling of a plenum mounted before the carb intake?

[dmcca]

First of all... this is my first post here... been lurking for a while, particularly in this thread, and ive gotta say its one of the best 2T reads around, well done everyone involved!



I have tested "boost bottles" between the carb and the reed.
They improve throttle response very low down in the revs off the pipe.
A couple of older quads used the idea, and one will hardly run at all off the bottom end if the bottle is removed.
But compared to a ATAC on the header they are virtually useless for improving power at the bottom of the useable band.
Whereas the wave/pressure action in the pipe is so much stronger that a flapper valve controlled chamber on the BSL500 gave 28% more power at around 7000 - was closed by 8000 and had virtually no effect at that rpm and up.

I'm interested in testing some ATAC style chambers... are there any rules of thumb to follow for the volume or positioning of the chamber? Thinking of adding one to a single cylinder 250 using the powervalve actuator to open a chamber. However the only way of doing it is to have a branch pipe about 150-200mm down the header that then leads to the chamber... how critical is the distance between the exh port and chamber entry?

[Grumph]

Some years back John Robinson of Performance Bike Mag did a test on an add on atac type chamber - Malossi brand i think.
Manufacturers recommendation was fit as close to the port as possible. Robinson agreed - didn't test at different placings, Fitted it at around 100mm out from the joint at the port. Results reasonable - fattened the curve a little at the bottom if I remember right.

[wobbly]

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.

[dmcca]

Thanks guys, appreciate the info. Im already running an ignitech ignition so could easily set up a solenoid off that. Will keep working on a reasonable design.



I posted about this a while ago.

Sorry, must have missed that.

[F5 Dave]

. . . .
The connecting tube should be about 1/2 the header dia, . . . .

whoa, that's interesting. that's quite a big hole & larger that many designs I have seen on production stuff. Hmm, maybe time to look at my GG300's setup.

. . . nah its got enough mumbo

[TZ350]

I bet the Aprilia is a much larger diameter disk valve.
So it is open wider for greater percentage of the time/area than comparable timing would have a smaller disk.If that makes sense.

Looking at your picture Husa, the Aprillia sure is shorter, it must have the primary drive on the other side.

249016
I am not sure what can be done to modify the cover and shorten the inlet tract down to look like the Aprillias, but I will have a look.

I understand how a taller port of the same timing and area is fully open for longer than an equivalent lower one.

But even after machining all the teeth off the starter gear on the back of the clutch hub the size of the rotary valve itself is still restricted by the inner sleeve protruding out of the clutch and that rides on the input shaft. Still I can get another useful 10mm overall and had already started making the parts required and will use them in the next engine.

[husaberg]

Looking at your picture Husa, the Aprillia sure is shorter, it must have the primary drive on the other side.

I am not sure what can be done to modify the cover and shorten the inlet tract down to look like the Aprillias, but I will have a look.

another useful 10mm overall and had already started making the parts required and will use them in the next engine.

Yeah it is a hard ask. The Rotax Aprilia is back to front compared to most Japanese engines. Its a Euro thing. I must admit to wishing my Berg was a right side kick occasionally

[dmcca]

Hmm, maybe time to look at my GG300's setup.


Funny you should mention the GG300... I was working on one the other week and thats what gave me the idea of adding a 'torque chamber' to my bike... the GG300 setup has a very small port thats linked the power valve assembly on one of the aux exhaust ports... its hard to see the exact size of the port but its very small, like 10-15mm tops. It sure has loads of bottom end though.

[Henk]

It sure has loads of bottom end though.

That would probably have more to do with the fact that it's a 300 than the extra port, my 360SX had so much bottom and mid I never bothered revving it out.

[wobbly]

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.

[husaberg]

Worth a look

http://www.emot.nl/webwinkel/index.php?act=viewCat&catId=saleItems

http://www.emot.nl/specials.php

http://www.emot-oldparts.nl/webshop/

http://www.emot.nl/fotoalbum/

Below engine of the Day any guesses? Answers on the back of a Blank Cheque to Husaberg.
Second pic is the split single "Twingle" piston supercharged DKW (3 pistons Single cylinder) well one spark plug. I was looking for a Pic of this a while back for Snow
3rd pic Rumi 125 http://2stroker.createforumhosting.com/rumi-project-hans-spaan-jan-thiel-t2652.html
4th pic Is that a pneumatic powervalve on the Casal 80? I have no Idea
5th Rumi

[wobbly]

The pic of the Casal is a Rotax copy style pneumatic powervalve - basically bloody useless as the instant you feather the throttle at any rpm the valve drops.
The pic of the Bartol I have seen before named as something else?? - but was the inspiration for me to use the FCR downdraft carb on the TSS500, same as
what is going on the F3 Superlight bikes I am building - Aprilia RS250 with 100+ Hp RZ400.

[F5 Dave]

Clear thinking when you lose any pretense of needing to be a road based engine. imagine the grief with plug fouling from the down angled cylinder on a few year old bike with a leaking tap as you tried to kick start it outside your girlfriends house with the rain just starting.

[TZ350]

I think it was Sonic-V who told me about a twin carb kart engine his dad successfully ran.

It had one carb opening before the other, that way he could vary the inlet tract cross section area for better carburetion, also it could be arranged to vary the inlets closing point too, also one inlet tract could be longer than the other.

The problem for me using this idea is the 24mm carb or equivalent area class rule which maybe makes two small carbs too flow restrictive and impractical, interesting though, and first time I have seen a twin carb cover, it looks a very good idea.

[sonic_v]

Two of these carbs (bored out to 16.97mm) will give the same venturi area as one single 24mm carb. However they have a 20.5mm bore thus should flow considerably better than a straight through 24mm carb.


http://www.tillotson-racing.com/carburettors/hl-166b-carburettor.html

[Henk]

1998 TTR600 Belgarda I had a while back (the one with the Ohlins shock) had a strange twin carb set up. The primary was a straight pull and the secondary a CV. I have no idea why they did this but it seemed to work OK.
It would probably only add to the complexity and setting up problems but if you were to go for two carbs there is no reason they would heve to be the same.

[husaberg]

249188
1998 TTR600 Belgarda I had a while back (the one with the Ohlins shock) had a strange twin carb set up. The primary was a straight pull and the secondary a CV. I have no idea why they did this but it seemed to work OK.
It would probably only add to the complexity and setting up problems but if you were to go for two carbs there is no reason they would heve to be the same.

The first bike I can remember with the 2 stage carb set up was the Villiers Starmaker stuff I poster further back.Yamahas had a big play with them in the mid 80's to 90's TT and XT etc. Honda with the XR series in the Mid 80's one thing they all have in common is they all went back to single carb set ups.The (TTR way be an exception to this rule)
2 carbs in my opinion = twice the drama.
I have enough trouble tuning one as it is.

Picture of updraft carbs on MZ and Suzuki 60's bikes a pic of the DKW 250 supercharged Twingle and lastly a Binks mousetrap variable venturi carb I had heard of them but I had never seen a picture of one.

[TZ350]

Two of these carbs (bored out to 16.97mm) will give the same venturi area as one single 24mm carb. However they have a 20.5mm bore thus should flow considerably better than a straight through 24mm carb.http://www.tillotson-racing.com/carburettors/hl-166b-carburettor.html

Thanks for that, I will have a look at them, and I guess that there is no reason for them to both be the same size, the low speed one could be smaller.


2 carbs in my opinion = twice the drama. I have enough trouble tuning one as it is.

Me Too, but I am starting to get the feel for tuning my HL-360 pumper,so tuning two pumpers at a time may be the next challenge.

249165

I very much like the look of the split inlet, I think if the inlet is say 50deg wide and closes 85deg ATDC then by closing the front carb at lower rpm you can advance the closing point to say 60 deg ATDC and as a side benefit this will also automatically increases the crankcase volume by the volume of the inlet tract to the back of the throttle plate of the closed front carb.

This extra volume exits during the suction and induction ramming phase but the extra volume is lost when the rotary valve closes the port off during the transfer phase so it doesn't help with bulk transfer.

One carb with two complete inlet tracts where one tract can be closed off was one of the ideas that Thomas and Bucket had come up with for varying the crankcase volume. With only one inlet tract open to the carb and the other left open to the crankcase this should give an apparently larger crankcase volume when filling (for less spitback) at lower rpm and then both inlets open to the carb and tighter crankcase volume for higher rpm.

249182

Ok so its a reed Kart engine. But an idea suggested by Wobbly is to have the carb(s) angled up on my GP engine, looks like a good idea.

[TZ350]

I was looking for something to independently drive a turbocharger for an F4 engine and started looking at pulse jets. I am not sure how good they would be for that but they sure look fun. http://www.pulse-jets.com/pulse3.htm

[Ocean1]

I was looking for something to interdependently drive a turbocharger for an F4 engine and started looking at pulse jets. I am not sure how good they would be for that but they sure look fun. http://www.pulse-jets.com/pulse3.htm

Couple of points.

They're hideously fuel ineficient.

They can be amazingly light for the thrust they deliver.

Oh, and if you show too much interest in the subject you'll be added to a long list of potential threats to national security by certain elements of the worlds security services. No joke.

[husaberg]

Couple of points.

They're hideously fuel ineficient.

They can be amazingly light for the thrust they deliver.

Oh, and if you show too much interest in the subject you'll be added to a long list of potential threats to national security by certain elements of the worlds security services. No joke.

Walter Kaaden was kind out involved with them in a way. After all they are just another use for an Expansion chamber. Edit they have Reed valves too.
http://forums.cycleworld.com/showthread.php?t=249421

Junkyard wars did one with ss exhaust bits and a Propane tank and a spark plug. It was loud and sounded like a V1. Funny that.

Interestingly enough the net is full of videos of people making Turbo's into turbojet engines. Reverse of reverse engineering perhaps.
http://www.youtube.com/watch?v=BZoymnZRBVc
http://www.youtube.com/watch?v=gNnSqmem3fs&feature=relmfu
http://www.youtube.com/watch?v=FIuHb4zzzO8&feature=related



Check out the carb on this 1958 MZ but Honda ran Flat slides in the 60's too I think on the 250/4 or 6 Edit at least as early as 1959

http://www.motohistory.net/news2008/news-jan08.html
http://www.cyclechaos.com/wiki/Honda_RC166
http://www.cmsnl.com/classic-honda-gallery/show_gallery.php?galid=106&gl_media1Page=1

[Ocean1]

they have Reed valves too.

They don't have to. Everything you never wanted to know about pulse jets: http://aardvark.co.nz/pjet/

[husaberg]

I was looking for something to independently drive a turbocharger for an F4 engine and started looking at pulse jets. I am not sure how good they would be for that but they sure look fun. http://www.pulse-jets.com/pulse3.htm
It would never pass a noise test anyway TZ
I had posted this somewhere else But thought it should probably belong here.

I could remember seeing these donkeys years ago. See attachments below
Delay boxs, old tech piggy back to CDI units.
This company is still in business too.
It was meant at the time to be a common Mod on proddy bikes. :innocent:

I have an article bellow that explains how they work and how to basically map an old style cdi unit. Attachments below
The Ignitech is the obvious top self bees knees set up, but it may be possible to provide a lower tech solution.
I seem to remember JayCar having a adjustable delay circuit.

http://http://www.jaycar.com.au/images_uploaded/LM555.PDF (http://www.jaycar.com.au/images_uploaded/LM555.PDF)
http://http://www.ehow.com/how_4827785_build-time-delay-circuit.html (http://www.ehow.com/how_4827785_build-time-delay-circuit.html)


Here is an exert off the net from a guy that builds Ignitions He mentions Buckets on his site to in regards to a Ignition he makes for the Honda 4 stroke single.

Engine revs Timing advance
1000rpm 26.0 degree
2000rpm 27.0 degree
3000rpm 25.5 degree
4000rpm 23.5 degree
5000rpm 22.0 degree
6000rpm 21.5 degree
7000rpm 20.0 degree
8000rpm 18.0 degree
9000rpm 15.5 degree
10000rpm 13.5 degree
11000rpm 11.5 degree
12000rpm 9.5 degree
"But the advance and retard goes the wrong way!?" you say. (Well one or two of you have.) I queried this with Rex, as I also thought that engines were supposed to advance the timing as the revs progressed, not retard it.
Rex replied:
"Since the early '80s much two stroke research has focused on electronics. We have seen the introduction of power valves to control the point of opening of the exhaust port. Initially this was performed by mechanical means, then designers found that to enhance the power band a control by an electric motor, itself controlled by a computer gave far more scope for power increases, especially in the midrange, just where you need to accelerate from a corner. Part of the search for midrange power focused on the ignition timing. It was found that beneath the power band created by the tuned exhaust system, more ignition advance could be given than could be tolerated at the peak horsepower rpm. A study of a MK 3 TZ350 curve will illustrate this. (Diagram to follow)
Then it was found that a further retard of the spark timing caused the exhaust pipe to run hotter, which affected the speed of the sound wave in the pipe. The net result was the pipe stayed in tune longer after peak horsepower by keeping the torque up.
We have found that retarding a fixed timing setup, by say 2-3 degrees, will give more power after peak horsepower, but there will be a drop in power on the climb up to peak horsepower. There a tailored ignition curve can give gains over the fixed timings we were used to in the early days of racing two-strokes. With limitations in engines by piston crown temperatures it pays to approach the design of the curve with care and dyno testing sometimes has to be verified with actual track testing. The same applies to other settings on the engine and the whole picture is usually a blend of art, science and experience, with failures on the way, such as holes in pistons! Hopefully this will give a brief explanation of why the general two-stroke ignition curve differs from a four-stroke curve which normally has a rise in ignition advance with a rise in rpm. Further study is recommended by reading books on the subject such as "Basic Design of Two-Strokes" by Doctor Gordon Blair and " Two-Strokes Performance Tuning" by Alexander Graham Bell."
So there you are. Years of research and hard work summed up in on or two paragraphs, supplied totally free to all of you people out there....thanks Rex.

There is also a Kiwi that makes ignitions too. Here http://www.pazon.com/ignition/ignition-products/

[wobbly]

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.

[Buckets4Me]

just to show TZ what has hapened to his old number #9
249334before
249335halfway threw

no after as it's having a bowel implant

[TZ350]

just to show TZ what has hapened to his old number #9

Looks better in Red and I think it will go well in F5 with the Honda100, I hope young Rob will have lots of fun with it.

[chrisc]

Anyone ever played with T125 lay down twins? Are they worthwhile/alright engines or dogs? They have twin carbs, anyone know if they're too big for buckets?

Any comments on the bikes in general is welcomed too.

I found a picture of an old racer: 249362

[husaberg]

Anyone ever played with T125 lay down twins? Are they worthwhile/alright engines or dogs? They have twin carbs, anyone know if they're too big for buckets?

Any comments on the bikes in general is welcomed too.

I found a picture of an old racer: 249362

Ask Pete Sales but they are 5 speed piston port iron cylinder points ignition and quite collectable.
There has been two on Trademe lately that have been raced.
I have a weakness for them and Wolfs but It would be a big ask.
They could be made competitive on a open track with MB5 cylinders but would need two of everything.
The carbs are odd and possibly oversize for the rules which would need to be equivalent to a single 24mm carb Which would be around 17mm I guess.
No doubt it could be done and it would be a hoot. They handle good even in stock trim and they would be beautiful done up as a replica of the 60's GP race bikes. But given how collectable they are now.
Should they be done?

[speedpro]

But given how collectable they are now.
Should they be done?

Hell yeah. Ideally you'd rip the motor out, toss the standard frame and then fit the motor into a late model RS125 chassis. :dodge:

[chrisc]

Ask Pete Sales but they are 5 speed piston port iron cylinder points ignition and quite collectable.
There has been two on Trademe lately that have been raced.
I have a weakness for them and Wolfs but It would be a big ask.
They could be made competitive on a open track with MB5 cylinders but would need two of everything.
The carbs are odd and possibly oversize for the rules which would need to be equivalent to a single 24mm carb Which would be around 17mm I guess.
No doubt it could be done and it would be a hoot. They handle good even in stock trim and they would be beautiful done up as a replica of the 60's GP race bikes. But given how collectable they are now.
Should they be done?

Thanks for that, I just found this:
"Flat parallel twin. Portirtg, piston controlled. Capacity, 124 cc. Bore and stroke, 43 x 43 mm. Compression, (from exhaust port closure) 7.3:1. Power, maximum claimed torque, 9.98 ft/lbs at 700 rpm, bhp, 15.1 at 8500 rpra Carburetters, twin 18 mm Amal MD, breathing through paper air cleaner."

Think the carbs changed over the years, this is meant to be the 1971 year I think.

I personally have no holds against modifying something that may be collectable for the sake of fun

[koba]

It may be better to start with something easier though...

[husaberg]

Thanks for that, I just found this:
"Flat parallel twin. Portirtg, piston controlled. Capacity, 124 cc. Bore and stroke, 43 x 43 mm. Compression, (from exhaust port closure) 7.3:1. Power, maximum claimed torque, 9.98 ft/lbs at 700 rpm, bhp, 15.1 at 8500 rpra Carburetters, twin 18 mm Amal MD, breathing through paper air cleaner."

Think the carbs changed over the years, this is meant to be the 1971 year I think.

I personally have no holds against modifying something that may be collectable for the sake of fun

Great Then I did have to ask.
As long as you paint it up look the ones I have posted.
I have at least one MB5 cylinder and head That I'd donate to the cause.

How many (MB5 cylinder and heads) do You have Speedpro Koba and and Dave?

Ps all the ones I have seen had 18mm Mikunis the Wolf was a debored 125cc to 90cc without the rev counter with smaller (I think) carbs.

PS i hope you have a lot of time machining ability or beer money

Checkout the kickstarter Gear selector mechanism.

[koba]

Bryce would be one to ask.

Avoid Terry 53 and his aliases on trademe, he has a lot of parts but I've had a good look through them and we differ on what constitutes "good condition" by about 100,000 KM and three years in the sea.

[TZ350]

Avoid Terry 53 and his aliases on trademe,

My experience with Terry53 was not so good, I won one of his job lot auctions but didn't get all the parts advertised in the auction photo, he only sent the junk and kept back the good bits. Of course I followed up, and from what I have seen and heard since, he may not be setting out to rip people off, he just seems to have a different idea about what integrity and fair value means.

249473 Steptoe and Son

From what I can see, Terry53 is the Steptoe rag and bone man of Trademe, basically Terrys stock is all other peoples junk and cast offs. And like Steptoe he is one of those people who paints a picture for themselves of gold and commercial possibility in everything they have, whereas other people with better personal hygiene mostly see it for what it is, junk.

Even if you have won an auction or closed a deal with him you may still be disappointed, as his word certainly doesn't seem to be his bond. Being a Steptoe, he will flog your part to someone else if he sniffs a better offer. If your lucky he will find you something else, that's even more decrepit than the original and tell you, you got a bargain.

I am sure if you meet him he would be approachable enough and I am not saying you won't find that essential bit there. But because he appears so out of touch with mechanical reality and has such a totally self focused business manner, it leaves me thinking you have only half a chance of a "value for money" outcome when dealing with him.

He has his opinions, the above are mine.

[NordieBoy]

Avoid Terry 53 and his aliases on trademe, he has a lot of parts but I've had a good look through them and we differ on what constitutes "good condition" by about 100,000 KM and three years in the sea.

Been waiting on a frame and some other bits from him for a while now.

[F5 Dave]

Yeah I went to pick up some MB cases from Terry for Speedpro & ended up buying some bare cases myself, but later to discover when i looked a bit better they had a crack near the gearset (I looked at the front where they usually crack if frame mounted from the front). Unrepairable Junk.

His house is just an explosion of rubbish bike parts.

T125 will not get anywhere quickly. But if you do have one I'm after some chrome seat strip & maybe headlight chrome surround. Maybe some forks.

[husaberg]

Old style 2 stroke tuning 1971 style Two wheels article hand written copy A tuned T125 could be made to see of a good t250 hustler supposedly.

If you were keen to move out of the 1960's port technology. Then maybe you could get something like (the Cylinder) this to work or similar.

[Frits Overmars]

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)249556, 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.

[husaberg]

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)249556, 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.

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

Great stuff Frits.
You are a 2 stroke God
But and I hate asking it.
What would this be then?
I can not explain what else it could be, and it is mentioned in the blurb from the Honda press release.
I realise the writer could be mistaken, but all the pictures of the non water injected bikes don't have this bit. Below in pic.
I have serious doubts it contributes much to the NSR500's Engine cooling.

I believe you have confused the lower radiator for the tiny radiator in the fairing nose up by the tacho that both myself and Bucketracer were pointing out.

[quallman1234]

Great stuff Frits.
You are a 2 stroke God But and I hate asking it.
What would this be then? I realise the writer could be mistaken, but all the pictures of the non water injected bikes don't have this bit. Below in pic.
I have serious doubts it contributes much to the NSR500's Engine cooling

Read the caption?

[TZ350]

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.

249567

In working out a curve to programe into the Ignitec we did various dyno runs with a straight line setting but different base advances. The runs were cut short as we were only looking at the lower part of the curve.

249566

Same runs compaired to my previous KX80 fixed ignition 16* BTDC (Red Line).

[TZ350]

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.

<iframe src="http://www.youtube.com/embed/KcNfci9OruU" allowfullscreen="" frameborder="0" height="315" width="420"></iframe>

Closing the valve to early ...... Now, could this be what is happening in the video clip of my GP125 on the dyno? As its coming up on the pipe you can see fuel being sucked in and then blow back appears at at the top end like Fritz described happens when the valve is closed to early.

Fritz is this enough blow back to suggest I should try closing the inlet little later.

[Frits Overmars]

....What would this be then? I can not explain what else it could be, and it is mentioned in the blurb from the Honda press release. I realise the writer could be mistaken, but all the pictures of the non water injected bikes don't have this bit. Below in pic. I have serious doubts it contributes much to the NSR500's Engine cooling. I believe you have confused the lower radiator for the tiny radiator in the fairing nose up by the tacho that both myself and Bucketracer were pointing out.
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.


Closing the valve to early ...... Now, could this be what is happening in the video clip of my GP125 on the dyno? As its coming up on the pipe you can see fuel being sucked in and then blow back appears at at the top end like Fritz described happens when the valve is closed to early.
Fritz is this enough blow back to suggest I should try closing the inlet little later.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 :shifty:.

[TZ350]

O, and one more thing, TZ350. Fritz is German. I am a Dutchie and I spell my first name with an s .

:Oops: ......


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.

Thanks for the incites into the inlet/carburation issues .......

[diesel pig]

O, and one more thing, TZ350. Fritz is German. I am a Dutchie and I spell my first name with an s :shifty:.[/QUOTE]

Sorry Frits TZ has been taken out and shot for that.:yes:

In your work with powervalves how important is it to get the valve to conform to the piston? would a gap of 2 to 3mm ruin the effectiveness of the system?

[Frits Overmars]

Sorry Frits TZ has been taken out and shot for that.That's a pity; you can do that only once. I would have suggested we call him TS350 for a week or so.

In your work with powervalves how important is it to get the valve to conform to the piston? would a gap of 2 to 3mm ruin the effectiveness of the system?Depends on what type of valve you are talking about. When it is fully opened, it should be out of the way and leave a smooth port roof. When it is closed, it should be as close to the piston as possible if you want to benefit from a longer working stroke. 0.5 mm would already have an adverse effect, but getting it closer to the piston ring would be dangerous.
What the valve normally does, is disturb the outgoing exhaust pulse. Then the return pulse will also be weaker and it cannot do so much harm, pushing fresh mixture back into the crankcase. Usually a gap of 2 to 3 mm will sufficiently wreck the outgoing pulse's efficiency.

[Buckets4Me]

That's a pity; you can do that only once. I would have suggested we call him TS350 for a week or so.

he use to race a t250 with rd400 barrels (isn't the ts just an off road version of it ?)

so probably wouldn't worry him to much

[TZ350]

... I would have suggested we call him TS350 for a week or so ...

there wasn't a Suzuki TS350 but calling me TS250 would do, they were a trail bike, I loved them ... :p

[husaberg]

there wasn't a Suzuki TS350 but calling me TS250 would do, they were a trail bike, I loved them ... :p

T350 it is then (the Rambler or was it Rebel) the T250 was the Hustler the T500 was the Titan or Cobra.

Not one guess for the engine of the day.
I posted last week was so here it is.
The Christensen.
Which could be a Dutch Name or a Neverlandish I guess.

The BMEP is a little low but it is the 1964 the interesting features are the cylinder coating and the head design and ignition I was surprised to see in the same Mag how long style modern Reeds have been around as well.

It is 132cc and a Kart engine an oversize carbs so it is not Bucket legal.

For TZ



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.

RG500 solution to short intake. This is what i was trying to explain last week.
Yow ling Had this on a Trademe thread

249612 249613

For Frits


the problem would have been far worse with double-walled light-alloy headers.

I do have to wonder what all the welding on the alloy headers is for because why wasn't it machined if it was single wall? Why would Honda do that?
I guess Jerry (Burgess) will be able to shed some light on this?

249608249609

[Frits Overmars]

.....I do have to wonder what all the welding on the alloy headers is for because why wasn't it machined if it was single wall? Why would Honda do that? I guess Jerry (Burgess) will be able to shed some light on this?I couldn't say. Let's hope Jerry will find the time to enlighten us.

[husaberg]

I mentioned that for the new build. The motor would be a more modern design. Which should have a 35 RWHP potential and a wider power spread.
This below shows just how old the MB100/H100 design is. The year is 1974.

249616

I love the motor don't get me wrong. It was the best engine available in the 90's.

The new motor will be based on newer generation 1990's technology that's all.

Unfortunately the rider will have less than 1% of the talent than the original rider of the bike in the drawing


249617

[husaberg]

I couldn't say. Let's hope Jerry will find the time to enlighten us.

Wob mentioned he was going to ask Pete Benson

I can't see why Honda would inject the water but I can't explain there radiator or the weird header design or there description.That I posted here.
From what i understad the origional Fleck papers were pure injection I whish I could find a copy of them.

http://http://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner?p=1130173462#post1130173462 (http://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner?p=1130173462#post1130173462)

Do you or anyone know anyone who could De-sighfer this?
It would seem to that it was annoying translated from English to (I guess Italian)

http://http://www.youtube.com/watch?v=ousgsIbW7WY (http://www.youtube.com/watch?v=ousgsIbW7WY)

I do however believe it (water injection) is a bit of a lame duck. As they results could be achieved better by adjusting the pipe length or volume with either a Atac valve and herp chamber or a adjustable length header design.
Which it what Wob said at the start nearly.

[Grumph]

Just to make some of you think, can i point out that we're not operating under FIM rules here.....
If you're already running a watercooled motor thee's nothing stopping you injecting ( maybe via a powerjet ) coolant into the inlet stream...
It's just cooling internally.....right ? No alcohol based fuel additives or coolants of course....

[FastFred]

I would have suggested we call him TS350 for a week or so.

What about about renaming TeeZee ... SS350 ...

SS to signify membership of the amateur tuners club and 350 for relative achievement with anything under a 100 being Junior status.

[F5 Dave]

Wasn't that a Harley, erm 'Fred'

[husaberg]

Wasn't that a Harley, erm 'Fred'

The only thing Harley on the SS350 was the badge and the crap styling.
249685
The SS is penance for the German Fritz/Frits mistake isn't it.
Putting TZ in the same sentence with SS unspoken would be cruel and unusual surely.

249687

I am the industry's tuner.What do you guys know I have a Vespa and a lot of issues with any ideas of mine being questioned.I work in the industry etc

On a completely unrelated mater maybe someone should post a on-board video of both Mt Welly and of the Wellington track to show Frits what sort of tracks you guys are racing on.

[Frits Overmars]

.....From what i understad the origional Fleck papers were pure injection I whish I could find a copy of them.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.

Do you or anyone know anyone who could De-sighfer this? It would seem to that it was annoying translated from English to (I guess Italian)
http://http://www.youtube.com/watch?v=ousgsIbW7WYTranslating 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.

I do however believe it (water injection) is a bit of a lame duck. As they results could be achieved better by adjusting the pipe length or volume with either a Atac valve and herp chamber or a adjustable length header design.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...

On a completely unrelated mater maybe someone should post a on-board video of both Mt Welly and of the Wellington track to show Frits what sort of tracks you guys are racing on.I would appreciate that.

[husaberg]

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. My Spanish would be up to it, and my 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 is 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.


Great stuff Frits
Re ajustable pipes
I know Cagiva ran a Hydraulic system and I think electric is to slow and to thirsty for power.
I also know that Cagiva ran the power valve (YAMAHA Style I guess) and Atac valve on the Randy Mamola bike.

I am stuck with a RC valve but it will be super easy for Wob to modify for my debored engine.

249692

I planed at a later stage to use a Greeves (woolley) style labryrinth seals with piston rings to seal the pipes.


When the Greeves Silverstone was first introduced it was recommended that the crank seals were changed after every meeting, as the wear rate was so high on the racing engine. The modern solution is to use Teflon coated oil seals. Before the times of Teflon coatings, Brian Woolley came up with an answer that not only worked but increased the time between servicing. His method entailed the use of Honda C50 piston rings to form labyrinth seals in place of the rubber seals. The rings were held in position by a steel sleeve which was a press fit into the crankcase, running in a slotted alloy carrier that rotated with the crank, the rings stopping any gas flow much in the same way that they do on the piston. As the seals on the standard 9E cases are smaller than the Greeves cases this modification may be a difficult one to embody without resorting to machining the seal housings, but for someone with machining know how it may be a feasible project. On the drive side the labyrinth seal can be located between the two bearings, the slotted carrier doubling as the bearing spacer.

My idea was compressed air. Easily rechargable light nice and simple, super fast and a little goes along way.
I planed to run the Water injection the same way and use excess air in the pipes to reheat it them.
maybe a little fuel if there wasn't enough in the pipes to work it what do you think.I also envisaged using air/electric to trigger the Atac

[TZ350]

maybe someone should post a on-board video of both Mt Welly and of the Wellington track to show Frits what sort of tracks you guys are racing on.

Here it is, Av on Ned Kellys bike at Mt Wellington. She did well in spite of the failing gearbox.

<iframe src="http://www.youtube.com/embed/eYEe8gIzs2I" allowfullscreen="" width="420" frameborder="0" height="315"></iframe>

249691

And Av herself ...

249690

Photos from Damions collection.

[Frits Overmars]

Great stuff Frits. Re ajustable pipes: I know Cagiva ran a Hydraulic system and I think electric is to slow and to thirsty for power.....My idea was compressed air. Easily rechargable light Nice and simple, super fast and a little goes along way.Compressed air is rechargeable and simple. I am not so sure about 'light and going a long way'. You might want to do a rough calculation on how much volume at what pressure you consume each time the pipe is moved. That could force you to use a bigger air bottle than you had planned...
A CO2-cartridge could be your way out: I estimate its energy density to be about a hundredfold better than air. Or, what I would do in Holland: use LPG (liquified petroleum gas, or autogas). I don't know whether you guys use the stuff in NZ, but I can get it at every street corner; the pressure is about 8 bar and being liquid its energy density (just talking about the pressure, not about what happens when you light it) is much better than that of compressed air.

EDIT: while I was typing, TS350 (well, allright, TZ350) was kind enough to post a Bucket video, which I am now going to enjoy. Thanks, TeeZee.

[husaberg]

Compressed air is rechargeable and simple. I am not so sure about 'light and going a long way'. You might want to do a rough calculation on how much volume at what pressure you consume each time the pipe is moved. That could force you to use a bigger air bottle than you had planned... A CO2-cartridge could be your way out: I estimate its energy density to be about a hundredfold better than air. Or, what I would do in Holland: use LPG (liquified petroleum gas, or autogas). I don't know whether you guys use the stuff in NZ, but I can get it at every street corner; the pressure is about 8 bar and being liquid its energy density (just talking about the pressure, not about what happens when you light it) is much better than that of compressed air.

EDIT: while I was typing, TS350 (well, allright, TZ350) was good enough to post a video, which I am now going to enjoy. Thanks, TeeZee.

Firstly whoops on the Spanish/ Italian. I struggle enough with Engerish as it is.
I have a mate from Basque (He would hit me if I called him Spanish) and a former work colleague who was a Spanish speaking Chilean and neither of them sound remotely like that fellow. As they now have a Spanglish accent.
He speaks so fast he could be from anywhere Latin based for me.
PS I wonder why if hes talking about the Honda wearing a Yamaha shirt who was he?
Apologies for my ignorance if hes Famous.
Matt Oaxley was the English commentary bit beneath i think.


Thanks I had not seriously considered CO2 and Nitrogen.
I think the safety police would frown on the LPG bit, but yes we do use it here.
The light bit was compared to batteries charging system and electric actuators or Hydraulics
I did a rough calculation on what my spreader air ram tailgate bit, me and a mate made up with a air ram single action with a spring return made from a hydraulic cylinder it has never needed filling but I get what you are saying. Paintball alloy co2 cylinder or a soda stream bottle was what i way going to try first.
The idea of the compressed air was I could use it for the water injection power as well as the reheat.
I believe the VW Beetle used it for a window washer from the spare wheel or similar.
Our races are generally 10 minutes or so.
The other idea was to fill up the frame spars. I was going to make up a frame with the tanks embedded in them if it worked. Added rigidity?

[Frits Overmars]

....Thanks I had not seriously considered CO2 and Nitrogen. .....The other idea was to fill up the frame spars. I was going to make up a frame with the tanks embedded in them if it worked. Added rigidity?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:
249693249703249694

[Frits Overmars]

..........

[Yow Ling]

Hi Frits, Not all the bucket racing is run on Kart tracks, In the South Island we are forced to race on full size tracks and street circuits here is a short video from a bucket race last weekend at Greymouth, there are 30 starters on the grid

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

[husaberg]

Hi Frits, Not all the bucket racing is run on Kart tracks, In the South Island we are forced to race on full size tracks and street circuits here is a short video from a bucket race last weekend at Greymouth, there are 30 starters on the grid

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

Awesome stuff.

I should be noted that the lap times are not much slower than the F1 bikes.
(Chris Elley Suzuki GSXR1000) was looking a little bemused when I pointed that little gem out.
If the Supermoto were to run the full track without the jump section they would wipe the floor with them all.

Where are all the Left handers.:innocent:

My father and a couple of his mates started this meeting 22 years ago to help the community get going (and to ride there old bangers) again after two back to back devastating floods in 1988.
The water was 1-2 meters through the town
The circuit is heavily cambered to cope with the Sub tropical down pours Greymouth gets at times.
The council kindly made the Traffic islands removable.
For years there was an agreement for the supermarket which was situating in the Pit area and the one outside the circuit to stay shut on the Sunday so there would be no loss of revenue for the supermarket.

[TZ350]

carb can be no bigger than 24mm (measured at the venturi as the manufacturer did...)

That is your interpretation of the rule , but not how the rule is written in the rules of competition

Jason may have been thinking of the taper that is designed into the carb (and also nessasery for extracting the plug during the die casting process) and that a 24mm carb measured at the venturi will taper out to 25-26mm at the engine side of the carb.

Team ESE are gearing up to manufacture their own style of carburettor that will be for sale to all comers at $385 and includes a full set of jets and needles, a conventional bike carb layout is like it is because that is the easy way to die cast them and keep manufacturing costs down there are better ways of getting a carburettor to atomise the discharged fuel droplets into the air stream.

The ideas are based on the kart carb where the high velocity atomisation area is separate from the flow disrupting throttle area. The prototype has performed well in dyno tests and on the track.

There will be enough made for everyone with the $$$ and in true ESE style when the production units are ready along with the sales add the design details will be posted so anyone who wants to can try their hand at making their own.

We are not expecting to sell many, there can't be that many race class's limited to 24mm carbs, purchasing carb bodies suiting our own ideas and then finishing them off ourselves and then offering them for sale to anyone and everyone at a reasionable price makes us a manufacturer albeit a boutique one.

As a manufacturer we specify our carb size as the total area measured at the narrowest point.

[husaberg]

Team ESE are gearing up to manufacture their own style of carburettor

The ideas are based on the kart carb where the high velocity atomisation area is seperate from the flow disrupting throttle area. The prototype has performed well in dyno tests and on the track.



EI Lectronishish but with std needles and Jets? I hope it is super short

[kel]

Team ESE are gearing up to manufacture their own style of carburettor that will be for sale to all comers at $385 ... for sale to anyone and everyone at a reasonable price makes us a manufacturer albeit a boutique one.

I love boutique, it'll go just nicely with my hand made swiss watch :facepalm: All joking aside (yes another attempt at humour Dutchie) if the performance is proven then $385 is more than fair for a hand made carb.

[husaberg]

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.

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...
.

That would be great to see the original papers thanks.

I am not that familiar with the CVT system workings other than scooters have them.:scooter:
I did however post some monotrack that had a Snowmobile transmission and motor that always interested me.
249741
My son also races a KTM 50 and I am forever amazed how well they go with a simple slipper clutch. They accelerate and lap as well as a well ridden 65.
The only thing I would find unnerving is on over run.
249740
That would take some getting used to unless they could lock back in on overrun.

[TZ350]

Taken from:- http://50iniepoca.forumfree.it/?t=43987929&st=75

....... The regular championship drivers all have 50cc...

Roffe's Hägarelli is 50cc for sure,about 15hp high torque......the main reason why he is fast are the racing skills of this viking and no brains.

The weight of Roffe is not so important as you think,only on a long straigt it matters a lot,on a short track like Adria you can be surprised what a heavy driver can do with a well tuned and geared 50cc bike

I am heavier than Roffe(110kg)and i can't beat him in the corners,he is a better driver,but there are a lot of leighter drivers who i keep behind me,if i can i will show you on Adria

René

A great 50cc race, http://www.pvlspecialisten.se/index/Movies 2009/Frohburg2009edit_0002.wmv

Originaly linked by Husaberg

[husaberg]

Taken from:- [URL]he regular championship drivers all have 50cc...

Roffe's Hägarelli is 50cc for sure,about 15hp high torque......the main reason why he is fast are the racing skills of this viking and no brains.

The weight of Roffe is not so important as you think,only on a long straigt it matters a lot,on a short track like Adria you can be surprised what a heavy driver can do with a well tuned and geared 50cc bike



Is that Roffe that Swede of MB50 disk valve Derbi cylinder fame?

http://translate.google.co.nz/translate?hl=en&sl=sv&u=http://www.pvlsverige.se/vrm/index/index22.html&ei=6RiITqL7LqbkmAXduKwr&sa=X&oi=translate&ct=result&resnum=1&sqi=2&ved=0CCAQ7gEwAA&prev=/search%3Fq%3Dhttp://http//www.pvlsverige.se%26hl%3Den%26biw%3D632%26bih%3D35 0%26prmd%3Dimvns

249742249743249744

[Henk]

A great 50cc race, http://www.pvlspecialisten.se/index/...9edit_0002.wmv


Couldn't be bothered quoting.

Unbelieveably cool

[F5 Dave]

Hi Frits, Not all the bucket racing is run on Kart tracks, In the South Island we are forced to race on full size tracks and street circuits here is a short video from a bucket race last weekend at Greymouth, there are 30 starters on the grid

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

We'd like to apologise these Si guys are keen on their dirty diesels.

Thanks Frits
Interesting what you are saying about PVs. I'd always thought of ATAC type chambers as mere wave disrupters but PVs as true timing changers. What you are saying is that PVs are less effective at this than I thought. This also poo poos something I'd read recently & questioned suggesting that non effective PVs (not super close to piston) would cause a bike to run badly, but if they are disrupting an out of freq returning wave the they are working as required.

Thank you for the insight.

[TZ350]

Is that Roffe that Swede of MB50 disk valve Derbi cylinder fame?

http://translate.google.co.nz/translate?hl=en&sl=sv&u=http://www.pvlsverige.se/vrm/index/index22.html&ei=6RiITqL7LqbkmAXduKwr&sa=X&oi=translate&ct=result&resnum=1&sqi=2&ved=0CCAQ7gEwAA&prev=/search%3Fq%3Dhttp://http//www.pvlsverige.se%26hl%3Den%26biw%3D632%26bih%3D35 0%26prmd%3Dimvns

249742249743249744

Dont know, but here is his fan club......... 249752

[TZ350]

Tec posts for Page 350 (but not complete yet)


Speedpro has won the race to be the first documented useful Bucket engine at 30rwhp


the powerjet switched with a solenoid is done just after peak power,as the engine is most efficient at peak torque,where it needs the most fuel.
But the carb doesnt know about efficiency, only bulk flow past the main jet - and the flow keeps rising as do the revs,so the mixture goes rich over the pipe ( thus reducing the temp).
By switching off some of the orifice area ( PWM is way better) we can lean down the fuel curve into the overev and heat the pipe up way more than is possible at peak torque.
On a HRC - RS250 for example the solenoids are activated at 12200 to 12800 ( adjustable plugs in the loom) and it will rev hard to 14000.
Without the powerjets it falls dead just past peak power at 12000.


STA or Specific Time Area, (Port Time Area) is at the heart of 2-Stroke port timing design. For what its worth and as I understand it. How to determine the STA numbers


To get around 38 crank Hp from an RGV100 ( to create mid 30RWHp) the T port needs to be up at 198 duration.
This is governed entirely by the blowdown available when the transfers are in the right place as well.
Having the T port as well as the aux ports may allow the exhaust port to be dropped a few degrees in duration,this then increases the range where the pipe is in resonance,giving a wider spread and no drop in peak power.
I need to measure one up though to see what is possible when it is sleeved back from the 56 bore to 50mm Edit, its 54 bore,so has a stroke of 54.5 unlike the earlyer engines.


"MSV is high at 25M/Sec", forget all that old shit - here is the go with squish.
In any race engine the squish height should be set at the minimum achievable,just shy of the piston tapping the head when overeved.
In a bucket where the norm is "only" 13000 there is no reason to have any more than 0.6mm.
The squish width based on MSV is a theoretical number of little relevance when we are running the piston in the powerband just short of hitting the head.
But with a parrallel squish ( ie curved same as piston dome rad - or a straight cut with minimal divergence) then in most cases we can use 40 to 45% squish area.
This generates MSV numbers in the high 30 M/Sec region.It has been stated in a few references that " high"squish velocity will bump up mid power and reduce the top end.
Yes, in a limited view of things it does.But now that we have digital programmable ignitions thats rubbish.
The high MSV increases turbulence in the end gases, this increases flame speed, and has the same effect as high com or too much advance.
Simply retard the timing and the rpm comes back, but you keep the power generated by better turbulence burning up more of the end gas trapped in the squish.

One point to remember is that the best radius on the squish corner into the bowl is no radius at all.A sharp corner with just with a rub of sandpaper to get rid of the ragged knife edge, works best.
And with any of the race type plugs we are using approx 1mm of unthreaded plug end should be protruding into the chamber.
The old B10EGV was originally designed to be used this way by NGK, but nowdays the trick plug is a R7376-10, this plug makes more power than any other tested with around +2 Hp better than an expensive Denso equivalent, here is the test i have shown before.


I haven't read the entire thread - I doubt anyone could - but balance factor discussion caught my eye.
The "conventional" factor of 50% plus works on upright cylinders - it makes them shake in the plane of the cylinder, ie up and down...this is generally the preferred direction as most frames are capable of damping vibrations in ths plane.
On horizontal cylinders an inverse balance factor is used. 25 - 28% works very well.This will make the motor shake at right angles to the plane of the cylinder...ie the preferred "up and down" direction...
FWIW I understand that parallel twin TZ's were around 33%....angled cylinders do make a difference. It ain't simple....


From the twostrokeshop

I don't want to lapse into too much tech-babble here; suffice to say, a crank that is 'under-balanced', such as the YPVS/Banshee crank, tends to create oscillations/vibrations in the vertical plane. This, for anyone who has ever converted an LC or YPVS 250 to a 350, is exactly the type of stronger vibrations you feel when switching from the 250 to the 350.

A crank's Balance Factor is typically expressed as a percentage figure. Normally the balance factor on a twin such as the RD is set at 50% to 55% of the total reciprocating mass - in this case 342g - so this would need 171g for the 50% case and 188g for the 55% case.

More on crank balance here. http://www.twostrokeshop.com/RZRD350_Banshee_TSS_Crankshafts.htm#sermon

Interesting look at TZ cranks. http://www.twostrokeshop.com/RZRD350_Banshee_TSS_Crankshafts.htm

And the different wear results of different B/E brg cages. http://www.twostrokeshop.com/peek_coated_big_end_bearing.htm


All that balance stuff on the Twostrokeshop site I did 3 years ago when starting the TSS500 project.
I was amazed when checking the RZ balance factors,and then found that someone at Yamaha also did it properly when designing the RD400, as it is set at 55% in both the drilled and leaded crank versions.
The stroker cranks I have for the RZ/LC all have Peek big ends,with Mallory balance weights,and I have the roller mains in stock.
The roller mains do have slightly more friction but will handle over twice the loading
,and last forever.
No one has tried Peek on the small ends as far as I know - but I have special silver plated small end bearings for the RZ/LC/Banshee.


The 90* crank versions I built for the TSS500 was an embarrassing nightmare.
The crank force simulation shows 31% less rocking couple and way less forces on the mains.
The first one I tested was absolutely fine vibration wise,but in reality it had,by shear chance an unbalanced prototype flywheel on it.
The two pistons rising to TDC close together create a vertical shake that vibes the bars like hell.
This can be offset by creating an opposite force in the flywheel,as I tested this by clamping a hose clip onto the ignition,with the screw positioned 1/2 way opposite between the two pistons at TDC.
But this "fix" creates a huge rotating out of balance force on one end of the crank - and the RZ case has enough trouble maintaining main bearing crush on a balanced assembly, without pounding it to death running an out of balance flywheel.
The carbs and bars vibrate enough to froth the fuel without soft manifolds - so the idea was dropped ( on my head).

Lots of interesting links on Husabergs original post


Balance with The hose clip innovative. These three engines I used were went to be like jackhamers until they were timed to fire as a single I have no idea why they ran smoother firing as a single I will try and find the articles as to why but I guess they didn't know why either other than the rocking.I understand it makes no sense.
In a single couldn't a narrow single couldn't experiments be carried out for balance factors on the ignition rotor as wobbly did. I am picturing something light a stealthy flywheel weight bolted on might not work on a a inner rotor type.
Attached is the Irving article on a 76 degree firing parallel twin crankshaft.

below is a exert from flashback fabrications on a Aemacchi Single balance.

This stuff relates to balance factors differing according to the frame thay are in.I do note the Commando and the Atlas were very much the same engine but the Commando is rubber mounted in its std frame and on a 20 odd degree angle in its std frame.


That's something lots of people don't understand. The huge forces don't go away, they are opposed, sometimes within the crank assembly and sometimes by a seperate rotating assembly. BMW of course used a seperate reciprocating assembly. The crank assembly counters reciprocating forces in one direction only and when there isn't any reciprocating force to counteract, at 90 degrees, it actually introduces an unopposed force. If a seperate rotating assembly is used for counterbalance then all the forces act through the crankcases and they can be large. The actual forces on bearings caused by the production of power are insignificant compared to the forces created by the movement of the parts whether reciprocating of rotating.
Any 90 degree engine with an even number of cylinders is great for this problem as there is forces acting at 90 degrees which balance out just sweet.

There is lots of interesting views and pictures of crank balance posted on the following pages …….


Here is the 90* side of the story.Interesting.

http://www.xs650.org.au/smoothness.htm


I think someone has posted this before, but I couldn't find it so here it is again.

http://www.saltmine.org.uk/shoeman/shoeman.html

Interesting read about tuning RD's.


MAHLE engine failure manual

http://www.mahle.com/C12572E600480825/CurrentBaseLink/W275ULLE756STULEN


Copper coating the rod or crank areas not needed to be hard, prevents the heat treat process from affecting the core - leaving it more ductile and crack resistant.
The company Heat Treatments have a paint on product that does the same job.


Bottom line is that when tuned for max power the disc valve does make more than a reed - those flapper things are always "in the way" to some extent..
But there are many trade offs.The disc will have NO power at all under the tuned for range, as it cannot suppress reversion at low rpm, and you cannot tune out the fact that the intake waves are telling the main jet signal all manner of lies,repeatedly.
Thus a reed engine can have much wilder exhaust timing and pipe design without giving away a heap of "under the pipe" power, and this exhaust tuning can have plenty of overev power as well, if that's what is needed.
An example would be the pipes I did for the fastest,and record breaking Honda RS250 on the salt last year, it had over 90RWHp between 12000 and nearly 15000,so would simply keep revving till the aero drag stopped it.
The peak power was "only" 96 I think, but it had plenty everywhere else it was needed.
To get that sort of overev power from the RV would mean it would be all but impossible to get it to carburate off the pipe, as the closing timing needed to get to 15000 would be mentally wild ( like 98*+ ).
And the last thing to consider is that despite what the supremely clever Frits and Jan say and did - in the last year of 250GP a Honda reed valve engine kicked Aprillias arse in the title - with a guy who cant ride a MotoGP bike to save himself.
The newer RSA engine is probably an unbeatable combination in 125GP, but for many other less demanding applications the reed has real, and useable, advantages.


With todays technology the bar can now be raised to around 40 crank Hp without too much drama involved, and thus achieving around 35 RWHp.
Its just a matter of careful parts selection and very careful assembly.

The alloy inserts for the TZ350 was the customers choice - once its all proven, and we get a handle on what the engine likes, then I will do some bronze ones.

AvGas in NZ is all LL100, this is low lead 100 octain.But the rating is defined differently in avaition.Its approx equiv to 100 "pump" gas, but has a lean rating of 100 and a rich rating of 130.
MNZ Appendix E defines avgas as max 112 MON amd max 108 RON.

Avgas, or any leaded "race" fuel reacts completely differently to unleaded pump gas.
In general terms the unleaded hates compression, but loves timing.Avgas is the opposite in that it makes more power up to the knock limit with more com.
Unleaded makes better power when run rich,avgas makes more the leaner you go.
Tuning in the old days with RS and TZ engines meant using lean mains and small powerjets ( 35 ) as turning off a big jet over the top would mean being too lean in the overev.
Nowdays the unleaded fuel runs rich at peak power, then uses a big powerjet ( 55) to create some heat in the pipe over the top.


Race gas bought in drums really is" low lead race gas", nothing wrong with it - but hard to get the same stuff in many places.
The stuff in tanks at stations/tracks is "old" avgas.The best, and only way to be sure of what you are getting is to go to any local airport and buy Avgas - it is tested regularly and is guaranteed to be fresh and to spec - has to be, or the Lycomings would all fall out of the air - bad.


Having multi cone sections gives the designer the ability to shape the power curve to the desired application.
Add to this 2 stage headers and you can achieve any wave amplitude correction needed with a 3 stage diffuser.
Here is a design I did for a Euro champ winning 50cc Malossi,it has a nozzle in the exhaust duct with an oval to round transition in the flange.
A two stage header, 3 stage diffuser with the steepest angle in the middle.
A killer pipe for the cylinder porting as it was used for long track racing only.
Graph is crank Hp


Pumpers are pretty easy to suss.
The pop off pressure simply sets the amount of fuel passed up to 1/2 throttle, transition from closed throttle,and around idle.
This should be set such that the bottom jet is no more than 2 1/2 turns out for the correct fuelling in the bottom end.
The pop pressure should be set with the needle and seat wet, and should hold its set pressure right up to the point of blowoff.
The top jet sets the fuelling past 1/2 throttle and mainly affects the ratio delivered at peak and beyond.
This should be less than a turn.
The pop off lever height sets the overall amount of fuel able to be delivered, the higher the lever the sooner, and further the needle is pushed off the seat, allowing more fuel to pass to the jets in total.


Re the lever arm height on the pumper - the free end should be set such that the middle of the arms end thickness is flush with the floor of the body.
Some say the top of the arm flush with the body floor, but most tuners raise this a little to 1/2 the thickness.


TeeZee some pumper carb tuning tips to go with Wobblys info. 247635

And here is something if we really cock it up..... ...... piston seizures explained 247636


One thing I completely disagree with in the piston seizure write up is that air leaks cause a lean condition.
This is utter bollocks, any engine with a case leak will run richer, the bigger the leak the richer it will run.
Caused by the fact that the case "pump" no longer works and the fuel air mixture isn’t being transferred thru the ducts.
If the engine is then leaned up to "fix" the incorrect mixture - then it seizes.


A leak between the carb and the reed or any intake will always add air going into the engine and create a lean condition.
A leak anywhere in the case, be it a gasket, a seal, or a pin hole in a casting will cause the engine to run rich.
Problem is that they then seize for no apparent reason when the jetting is then "fixed".
So its always wise to make a set of blanking plates and or use a rubber bung with a bolt that expands it into the pipe manifold, so that a leak down test can ensure no case problems exist.


Piston specs here inc ring peg locations
http://www.pvlsverige.se/vrm/kolvar/kolvar.html

This is real Gold


Small problem you have overlooked with that piston.
Its only 50mm long and with a 100cc bucket we are usually using the 50.6 stroke cranks, thus the exhaust port will be exposed to the case when the piston is at TDC, unless you raise the port floor.
The 1.2mm ring is too wide to be running over 14000 rpm as well, and the huge hole they have around the pin will create port linking issues with a wide T port or a big 3 port setup.
The 50mm oversize RM85 pistons I got are 51mm long, just enough to work OK, as are the 50.5mm CR85 +3mm ones for Mikes engine.
Also the TM carb is an old design, one of the first semi flat slide carbs - the later TMX and PWK types flow alot more air due to much superior slide shape.

Effects of changing compression ratios, complete with dyno graph.


Dialled it in best we could with ignition and jetting but suspected it was a bit over compressed so we put a gauge on it, 195psi cranking, Blue line.

Interesting to see how the power changed with compression.


Everyone uses the chamfered pin with plain clip now - but for years we had to cut the inner leg off TZ clips and add the chamfer to prevent the clips from popping out.
Dont know if Irving was the instigator of the idea, but it works a treat.

Primary com of 1.37 would be about right for the average transfer duct and port geometry being run.
If the descending piston compresses the volume, then its part of the case compression if its connected when the piston port is closed.

I think this is one of the big ideas that have come from the work on the flow bench. You need to look at the whole post and pictures, the idea is that a small deliberate step gives better flow than a perfect match.


TeeZees carb with a small even 0.5mm step all around the edge will make it easy to take off and refit without loosing any air flow at the joint through any slight miss alignment.

You need to read the whole post for Wobblys thoughts on Com Ratio.


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..

Compression ratios and what works …….. you need to go to the post.


Thanks for expanding on that ........


Current thinking in a road race setup would indicate 145/90 is the outer limits of whats needed so this could be tried, opening up one side at a time.


Just cracked open a Rotax 256 had 155/90 as the disc timing......... kart blokes bless em all


BMEP the gauge that allows the serious engine developer a direct way to compare different internal combustion engines, from lawn mower to massive prime movers.
2-T BMEP (psi) = HP x 6,500 / L x RPM
4-T BMEP (psi) = HP x 13,000 / L x RPM
where L = Litre and converting PSI to Bar is Bar = PSI x 0.069


Take the very best 125GP engine specs and plug that into the formula.
We have 50Hp times 6500 divided by 0.125 times 13000 = 200psi which is a real, usable number, I see all the time.
Use the same numbers for a 4T and we have 50 times 13000 divided by 0.125 times 13000 = 400psi , that is completely impossible, and this is the whole reason a 2T is superior to a 4T when compared apples for apples.

[bucketracer]

Buckets is not the only thing Team ESE gets up too.

Phillip Island Moto GP 2011

249757

Chambers in the red hat talking with Rossi after his off, NedKellys just off screen.

Rossi would have been interested in Teaming up for the 2 Hour but his contract with Ducati won't let him.

and Chambers recons million dollar Ducatis fill up with dirt during a crash just like Buckets do.

Well maybe Chambers didn't actually talk with Rossi but that is Chambers in the red hat.

[husaberg]

Tec posts for Page 350 (but not complete yet) When is someone/anyone going to write a modern two stroke tuning book? Well then!
Dont know, but here is his fan club......... 249752 249778

Phah Swedish girls. They kind of look a little plain compared to Kiwi Chicks. Like these below

http://www.google.co.nz/imgres?q=kiwi+chicks&hl=en&sa=X&biw=1280&bih=827&tbm=isch&prmd=imvns&tbnid=EJiQF2BAsWJQrM:&imgrefurl=http://www.scoop.co.nz/stories/AK1109/S00394/two-more-kiwi-chicks-hatch.htm&docid=ZszoEuGo5IqK_M&imgurl=http://img.scoop.co.nz/stories/images/1109/a6bfe212b0594916515d.jpeg&w=400&h=301&ei=q0CuTouJBunImAWGuYzODg&zoom=1&iact=hc&vpx=499&vpy=318&dur=3859&hovh=195&hovw=259&tx=104&ty=222&sig=105646614974927479953&page=5&tbnh=132&tbnw=178&start=91&ndsp=25&ved=1t:429,r:8,s:91

[Buckets4Me]

249783tada

[wobbly]

The author of the best 2T simulation software package available, and believe me I have used all of them including Fluent driven by Solid Models and full Cd mapping,
could not make a living out of selling his software.
I talked to him about doing a book, and including his software as a package, just like Blair did many years ago - that I thought was a godsend.
Read the book, then use the software to develop your engine.
There is no money in it at all, for the effort and costs involved in getting it to print.
Maybe sell it online, as a downloadable package,but again, the costs of setting up that scenario would mean questionable profitability.
Blair was a paid Prof, Neels van Neekerk the software author is a Head of Engineering Research, they have jobs to pay the bills.
The last Tech book that made any money was and is a Uni manual - Theory of Machines and Mechanisms, that I bought as it had a disc with engine balancing code on it.
Its author is Prof of Engineering at Uni of Wisconsin - Madison.
None of the traditional print houses is interested in tech manuals, even if Steven King were to do one.
At this point its up to you to buy the software and learn, but thats also hard in that crap in = crap out, so you have to then build crap to learn that it is - Catch 22, that made money.

[husaberg]

The author of the best 2T simulation software package available, and believe me I have used all of them including Fluent driven by Solid Models and full Cd mapping,
could not make a living out of selling his software.
I talked to him about doing a book, and including his software as a package, just like Blair did many years ago - that I thought was a godsend.
Read the book, then use the software to develop your engine.
There is no money in it at all, for the effort and costs involved in getting it to print.
Maybe sell it online, as a downloadable package,but again, the costs of setting up that scenario would mean questionable profitability.
Blair was a paid Prof, Neels van Neekerk the software author is a Head of Engineering Research, they have jobs to pay the bills.
The last Tech book that made any money was and is a Uni manual - Theory of Machines and Mechanisms, that I bought as it had a disc with engine balancing code on it.
Its author is Prof of Engineering at Uni of Wisconsin - Madison.
None of the traditional print houses is interested in tech manuals, even if Steven King were to do one.
At this point its up to you to buy the software and learn, but thats also hard in that crap in = crap out, so you have to then build crap to learn that it is - Catch 22, that made money.

Shame really.
Because Jennings is so 70's Bell is like so 80's Robinson is so early 90's
I suppose even if it was printed in electronic form, someone would just pirate it anyway.
After all the current 2 stroke tuners are gone it will probably just die (The 2 stroke)
Without Bell. I would have probably Just brought a diesel.:facepalm:

It would be interesting to run a simulation on say Bells RM125 road racer tuning example. This time with 2011 technology with a modern pipe design and modern tuning techniques to see just how far the 2 stroke has came in 30 year's since bell probably wrote the book.

What good is knowledge if it can't be shared. (It not a slight a you Wob you need to make a living and it's not easy being self employed)

Four stroke are just so boring. Honda basically done it all in the 60's. The 2 stroke as so much more to give.

For instance F5Dave made a comment regarding the lack of 2 strokes in the bucket field of the race that Mike had posted. The GM street race.
Well I sure as hell noticed the same thing.
I just added up the feild out of the program.

Out of 29 guess how many were 2 strokes.
11 no, 10 no. 9 no, 8 no. 7 no, 6 I wish.

I count 5. Yes only 5.
It could have been 4 shit. I am not sure about one of them, (Johnny Buchanan Honda G4)

It was, As always one of the bigger classes. In fact the biggest if you add in the fact the the larger classes were mixed capacities.






Exit soapbox Ning Ning 249812



For Frits and Wob. How much difference do the carbon pipe covers and or pipe lagging that Aprillia and others used to run make HP wise in top end?
Is there still a place for them or has the electric solenoid PJ rendered them redundant?

[bucketracer]

[R RATED]When is someone/anyone going to write a modern two stroke tuning book? Well then!

This thread and others have a lot of info .........

[Frits Overmars]

This thread and others have a lot of info .........
I agree with Wobbly (I usually do): there is no money in paper books on two-stroke technology (there is little money in paper books period, unless you happen to write Harry Potter stories). But you'll find a lot of present-day info in forums.
ESE's works engine tuner is a good example, and of the numerous other forums that are 'open to the public' I would recommend www.pit-lane.biz (http://www.pit-lane.biz). It's French-based, but yours truly and Jan Thiel are allowed to write in English (and I post all my photos in Dutch without anyone noticing:shifty:).
A good starting point would be here: http://www.pit-lane.biz/t117p246-gp125-caracteristiques-aprilia-rsa.

Reading through the above posts my eye fell on this remark from Wobbly, talking about reeds versus disks:

despite what the supremely clever Frits and Jan say and did - in the last year of 250GP Honda reed valve engine kicked Aprillias arse in the title - with a guy who cant ride a MotoGP bike to save himself.First of all, thanks for the flowers, Wob (like I just said, I usually agree with mr. Wright:whistle:).
Second: it should read Jan and Frits, not the other way round; Jan did much more than my humble self in making the two-stroke so suppreme that it had to be put down by the Honda-Dorna combination.
Third: I would not say that a Honda reed valve engine kicked Aprilias arse. The Aprilia riders did that all by themselves, stealing points from each other and shooting each other off. Not even Honda-driver Hiroshi Aoyama would dispute that the Aprilias were faster.

[Frits Overmars]

...For Frits and Wob. How much difference do the carbon pipe covers and or pipe lagging that Aprillia and others used to run make HP wise in top end? .....Is there still a place for them or has the electric solenoid PJ rendered them redundant?"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.
249819

[Buddha#81]

For instance F5Dave made a comment regarding the lack of 2 strokes in the bucket field of the race that Mike had posted. The GM street race.
Well I sure as hell noticed the same thing.
I just added up the feild out of the program.

Out of 29 guess how many were 2 strokes.
11 no, 10 no. 9 no, 8 no. 7 no, 6 I wish.

I count 5. Yes only 5.
It could have been 4 shit. I am not sure about one of them, (Johnny Buchanan Honda G4)

It was, As always one of the bigger classes. In fact the biggest if you add in the fact the the larger classes were mixed capacities.





Sorry man Johnny was on a GL145.......stink aye and 2/3rd of the field was fxr's or fxr powered......

[dmcca]

At this point its up to you to buy the software and learn, but thats also hard in that crap in = crap out, so you have to then build crap to learn that it is

Ive been using engmod2t for a little while now and initially though there were limitations in what it could do but now realise that i'm the real limitation... there are so many ways to measure and input data and its extremely hard to know if you're doing it right...

Im guessing the only way to tell is test with a dyno and compare results, then alter the way data is entered until dyno results consistently equal sim results...

Are there many engmod2t users on KB? might be worth starting a thread asking/answering questions.

[husaberg]

"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.
249819

Thanks Frits I had never considered the heat soak from the pipe to the Crankcase.

Given the bucket rules we run under AC 125cc with 24mm carbs and LC 100cc open carbs what would you go for.
The only 6 speed one is the Kawasaki in the Disk valve models and GP125 Suzuki with 5 basically all the reed valve ones Case or cylinder are 6 speed and We are not adverse to deboring or destroking a 125cc Later model engine.
I am thinking open race tracks here in the South Island. Sorry its a curly one.



Other question anyone no the firing order on a TZ750 I was reading something the other day that suggested the cylinders fired in Pairs the outer two and then the inner two together. If they do I wonder why? Was it because of the way the cranks were made and Joined?

[Frits Overmars]

I would stay away from air-cooled racing engines at all costs.Then again, I would find a way around the carb diameter limitation; take a look at www.pit-lane.biz (http://www.pit-lane.biz) where I explained the backgrounds of my 24/7 inlet system.

[husaberg]

I would stay away from air-cooled racing engines at all costs.Then again, I would find a way around the carb diameter limitation; take a look at www.pit-lane.biz (http://www.pit-lane.biz) where I explained the backgrounds of my 24/7 inlet system.

Awesome PG 13 found it. Interested to know what the Air cooled rear disk valve engine is around page 5 .249820