ESE's works engine tuner

[husaberg]

Maybe you could bring them just a little bit closer - isn't there a deep spot in the ocean somewhere?

Couldn't you just slip on in a 250 engine? I hear they went kind of ok with one in them? (for a 2 stroke.)
I assume the chassis is nearly identical. Are they?

Couple of Cobas.
JJ-Cobas with Autisa engine (designed by Jan Thiel) 1985

Seen this today regarding Bill Buckley.
http://www.kiwibiker.co.nz/forums/showthread.php/145040-Bill-Buckley

[Grumph]

Maybe you could bring them just a little bit closer - isn't there a deep spot in the ocean somewhere?

From what he told me, when he asked about buying them as a job lot, the response was along the lines of "New Zealand ? Yes. that should be far enough away....." Whoever he talked to at the factory just wanted to get rid of them.

Your bad luck the container reached here instead of falling overboard.

[Brian d marge]

Couldn't you just slip on in a 250 engine? I hear they went kind of ok with one for a 2 stroke.
I assume the chassis is nearly identical. Are they?

Couple of Kobas.
JJ-Cobas with Autisa engine (designed by Jan Thiel) 1985

Kind sir , please stop posting naughty pictures on the internet , my old heart hasn’t seen this much action since Angela Peabody showed me her "etchings"

Stephen

must have a lay down ......

[husaberg]

Kind sir , please stop posting naughty pictures on the internet , my old heart hasn’t seen this much action since Angela Peabody showed me her "etchings"

Stephen

must have a lay down ......



The Japanese sure do like their cartoon naughtiness. I guess the fetish has er...rubbed off on you to.
Tally ho and tootle pip.

Add Honda RS125 stuff later.... It is after all the for many a day of worship and I bet if he was into bikes (GOD) he would have rode a Honda.:shifty:

[TZ350]

EngMod2T

253016

253009

I had previously built up an EngMod2T model of my existing motor that pretty much matched its real life dyno graph.

253008

And then added a Pipe designed by Frits, the old plenum and my triple port cylinder and got 40+hp. It exists in theory, now could the race be on to see who can make the first Bucket to touch 40rwhp in reality!!!!

[koba]

EngMod2T

253013

253009

I had previously built up an EngMod2T model of my existing motor that pretty much matched its real life dyno graph.

253008

And then added a Pipe designed by Frits, the plenum and my tripple port cylinder. Could the race be on to see who can make the first 40rwhp Bucket!!!!

Fecking impressive.

Poor 1970's commuter-bike crank... 13500 sounds like a big ask.

[TZ350]

Poor 1970's commuter-bike crank... 13500 sounds like a big ask.

Phenolic main brgs with RGV250 rod assembly has proved reliable so far ....

[koba]

I've been playing with simulations a bit.

In MOTA I've input a model of my current engine, as mentioned earlier It seems around right but perhaps a little optimistic on the outright horsepower.

Here are before and after curves of the current plan.
Subject to change as I learn more.
253014

I found I can get much higher numbers but I think it may be a quirk of the maths behind the sim or something. I don't trust it to deliver in real life.

253019

I'm especially mindful of wobbly's comments (ages ago) regarding "sucking real hard on crappy transfers".
I'm probably going to spend a bit of time working out crank case volumes because while I know it is a bit old fashioned I know my motor is too!

[koba]

Phenolic main brgs with RGV250 rod assembly has proved reliable so far ....

True, you guys have done very well when it comes to reliability. The odd pop, but that is to be expected considering the nature of your endeavours.

I've been meaning to ask, has that Belzona remained attached to the piston?

[TZ350]

You see what I mean about Mota over stating it but I think you will fined the rpm and the shape of the curve will be pretty well right.


True, you guys have done very well when it comes to reliability. The odd pop, but that is to be expected considering the nature of your endeavours.

I've been meaning to ask, has that Belzona remained attached to the piston?

Yes, the Belzona is still there ... and yes, I think the cranks can be made reliable with original Suzuki RGV rod kits and decent main brgs, the same could be done with TF/TS's and then they should be good for 13,000 + too.

[koba]

You see what I mean about Mota over stating it but I think you will fined the rpm and the shape of the curve will be pretty well right.



Yes, the Belzona is still there ... and yes, I think the cranks can be made reliable with the RGV rod kits and decent main brgs, the same could be done to TF/TS and then they should be good for 13,000 + too.

We'll find out eventually as I will get it to a Dyno sometime.

Good to hear about the Belzona, that re-assures me about one of the options for my motor which is the CR85 3mm oversize piston that wobbly posted about. Don't know for sure if it will have bridge oiling holes but it is quite likely.

I'm living in fear of 40hp buckets now...

[TZ350]

I'm living in fear of 40hp buckets now...

Probably no need as I have single handedly proved big hp on its own doesn’t win races.

[koba]

Probably no need as I have single handedly proved big hp on its own doesn’t win races.

Cue the ring-in...
At a GP on a big track HP means a lot more than on a kart track. (Stating the obvious!)

I've steered away from too much power too soon on purpose.
I wanted to be able to ride what I have (maybe 14hp) to it's potential before I moved further.
I learn best in small steps when it comes to riding. Some people do fine when chucked straight into the deep end but I'm well aware I'm not one!

It could still go quite a lot faster on a kart track with some decent suspension work. However, I'm reasonably satisfied I've lapped Kaitoke at least close to it's current top speed.
The next stage is a jump in power but more importantly a refinement of the curve.

I'd love to get flash boingers on it but It is just so much easier to do HP on the cheap.
HP wins, the boingers will have to wait for a bit. I did get a 2nd hand GSXR shock off Richban but I think it will need a lot of thought and modification to have a chance of getting it to work better than the std (pretty bad!) rear shock.

[Farmaken]

EngMod2T

253016

253009

I had previously built up an EngMod2T model of my existing motor that pretty much matched its real life dyno graph.

253008

And then added a Pipe designed by Frits, the plenum and my tripple port cylinder. Could the race be on to see who can make the first Bucket to touch 40rwhp !!!!

:shit::shit::shit:Did you say 40 :shit::shit::shit:

[husaberg]

:shit::shit::shit:Did you say 40 :shit::shit::shit:

Shouldn't we achieve he first 35hp bucket first?
Vanessa is going to be very upset if some other starlet with fuller curves upstages her:shifty:
Here is some Honda RS125 stuff. Love the 90's colours.
Where my Hair Gel . ooh... OK Never mind the gel where's most of my hair gone.

[bucketracer]

Six months ago people were scoffing at 30hp, in fact a while ago an "Industry Insider" was telling us low 20's was the best he had ever seen/managed in 200 dyno sessions from a 125 air cooled rotary valver with a 24mm carb. Our foreign correspondent didn't seem to hold out much hope of TeeZee bettering it, and as he tells it, he should know, as he tunes strokers for a living. And by his own admission, is perfectly qualified to judge.

253033 253032

Here you go TeeZee a fancy new updraft carb ...

[kel]

HP wins, the boingers will have to wait for a bit. .

Go for the suspension! Im still buzzing from riding Arrons bike in the 2hr, so much so Im afraid to get back on mine for the let down I know it will be. Arrons motor is standard bar the high comp piston, was the brilliant handling that made it so quick.
Big power and flash suspension now that would be the ticket!

[koba]

Go for the suspension! Im still buzzing from riding Arrons bike in the 2hr, so much so Im afraid to get back on mine for the let down I know it will be. Arrons motor is standard bar the high comp piston, was the brilliant handling that made it so quick.
Big power and flash suspension now that would be the ticket!

It would wouldn't it!

There are multiple options open to me at this point.

More power is definitely high on the list as all it really requires is time and thought. I may have to buy a sheet of steel to make a pipe but that's about it.

Is Aarons bike an FXR?
My bike in its current state gets destroyed by a std FXR in a drag race...

[koba]

Six months ago people were scoffing at 30hp, in fact a while ago an "Industry Insider" was telling us low 20's was the best he had ever seen/managed from a 125 air cooled rotary valver with a 24mm carb in 200 dyno sessions. He didn't seem to hold out much hope of TeeZee bettering it, because he should know as he tunes strokers for a living and by his own admission, is qualified to judge.

253033 253032

Here you go TeeZee a fancy new updraft carb ...

I had a re-read of some of that stuff recently.

I'm still amazed at how much he acted like a childish fuckwit.

[gamma500]

253008

And then added a Pipe designed by Frits, the plenum and my tripple port cylinder. Could the race be on to see who can make the first Bucket to touch 40rwhp !!!!


VERY impressive :Punk:, waiting eagerly to see the dyno results.

[husaberg]

I had a re-read of some of that stuff recently.

I'm still amazed at how much he acted like a childish fuckwit.
Why be amazed he is a childish FW and a racist bigot as well.

Kaw 900cc vs Rs125 seems fair!

[husaberg]

Honda rs125 Nx4 a bit dog eared and er......stained:innocent:

[husaberg]

Six months ago people were scoffing at 30hp, in fact a while ago an "Industry Insider" was telling us low 20's was the best he had ever seen/managed in 200 dyno sessions from a 125 air cooled rotary valver with a 24mm carb. Our foreign correspondent didn't seem to hold out much hope of TeeZee bettering it, and as he tells it, he should know, as he tunes strokers for a living. And by his own admission, is perfectly qualified to judge.

253033 253032

Here you go TeeZee a fancy new updraft carb ...

Their Website is basic but there is a Kilt 24mm carb listed for 400NZD

How much was the one Wob posted?

on the ibea site look under old models
http://www.vroom.it/en/kart-news/10424/vroom-exclusive-kilt-new-carb-unveiled
http://ibeacarb.com/ibea/index.html
http://www.kilt-karting.be/kilt.htm
http://www.ekartingnews.com/viewtopic.php?p=485828&sid=c07e9905bc779f609730f65c0dfa91f3
http://www.vroom.it/en/kart-news/10426/vroom-n127-december-2011

[jasonu]

I'm living in fear of 40hp buckets now...


Probably no need as I have single handedly proved big hp on its own doesn’t win races.

I'm not worried about the 30hp buckets (yet).

[kel]

My bike in its current state gets destroyed by a std FXR in a drag race...

Your seat of the pants dyno must be reading less than 14hp if you cant out run a standard FXR

[F5 Dave]

Depends on how much of the curve is above a certain point. If you have a flat curve between gear changes then you will have a greater mean time spent at that power figure, more area under the curve as opposed to something that only touches a figure for a while.

[koba]

Depends on how much of the curve is above a certain point. If you have a flat curve between gear changes then you will have a greater mean time spent at that power figure, more area under the curve as opposed to something that only touches a figure for a while.

That's pretty much how it feels. FXR's feel like they pull reasonably well from 7 to 12.

My bike feels like it has lump around 6 and another lump around 8. :crybaby:

[pugs]

I haven't read the entire thread - I doubt anyone could
I did.. really.. finally managed to get it done after more than a month..:facepalm:
Thank TZ350 & ESE's team for such a great thread, Mr. Wayne & Mr. Frits, & all contributors (hell, even ss90) for superb contribution.


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.
So true.. I feel like I just read a great adventure book, which contains a lot of knowledge about tuning 2-stroke engine, and yeah, this is much much better than harry potter...:corn:

Btw, sorry I just introduce myself now after a lot of material that I got from this thread. My name is Thomas, Indonesian, mechanic, (yeah just like ESE's mechanic there, but much worse than ESE's Thomas I reckon, since I just starting this 2-stroke learning)

Currently I'm trying to achieve 45+ rwhp from KR150 with pump gas (92 octane) for daily ride and occasionally night sprint (should be easy for you guys?), and yeah this thread really help me to determine, which part of KR that need to be optimized.

This is what I achieved few months ago with light exhaust porting work, shimmed head, custom expansion chamber(blairs), programmable ignition (cpms new amateur) and PJ34 carb. Gotta find new way to bump the power since now I use a bore-out PE28 though..
Next stop, I think is some crank & transfer work and FOS exhaust.

Port map comparison for std KR150 (red), my mildly ported (blue) and rotax 129 GP (monardi rsw?)

[TZ350]

Very interesting port layout and graph, it would also be interesting to see some pictures and maybe a Youtube clip or two of the night sprints and bikes. Are there people who make custome pipes?

[koba]

We race KR150's here too in our streetstock class. They are unmodified. They go very well too.

[dinamik2t]

Hey Pugs!
Are the races you mention like the Thai drag races??
We drag-race mopped engines/bikes here in Greece too, like those races. :)

[F5 Dave]

I. . .

Currently I'm trying to achieve 45+ rwhp from KR150 with pump gas (92 octane) for daily ride and occasionally night sprint (should be easy for you guys?), and yeah this thread really help me to determine, which part of KR that need to be optimized.
. . .

Hawweeba~!:eek5: the is equiv of getting 30hp from Mikes 100. Except his is a dedicated race bike on decent petrol & running high revs that would shorten engine life beyond what is tenable for a road bike. I hope you have a spare engine if its your daily ride.



erm sorry I'm a bit lost with the labelling of the portmap. Sub exhausts well above main?

[wobbly]

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

[dinamik2t]

Wob, an irrelevant question:
Is there any power or consumption benefit from turning the spark plug "opening" (created by the ground electrode) towards the intake?

253217

Ahm..so, I used my lame painting skills! With -tons of- imagination this could be an upside-down picture of the comb. chamber and the plug 'looking' towards the intake. The spark and the flame-front would firstly move towards the intake, starting combustion from there (?). Am I talking nonsense?:scratch:
And the proper position can be achieved by adding washers beneath the plug washer.

[F5 Dave]

Kawasaki have had subs above the mains for along time - they have a PV in the subs , not the main port.
I did a 125 for karts a long time ago that won a National Title, but I dont think that the idea is specially better or trickshit.
Only Kawis I've had or seen have had PVs in main & trapdoors for subs, in KX250 case I think there was 2 at different heights - but it was a long time ago & I was wondering how many of those would be still operating in 4 years time when they became trail bikes so complex was the system.

[pugs]

Very interesting port layout and graph, it would also be interesting to see some pictures and maybe a Youtube clip or two of the night sprints and bikes. Are there people who make custome pipes?
Sorry TZ, no vid yet..
There's a lot of custom pipe craftmen here, with each one of them using their own formula/experiences (or maybe based on blair's works? Well, it is their own confidential I guess). For me, I was just guessing the temp(very bad thing, but no egt sensor yet at the time), then use blair's formula, make the layout, and give it to some craftman..


We race KR150's here too in our streetstock class. They are unmodified. They go very well too. Well, it's the most favorite legal fast-bike here.. At stock form, it's comparable with streetstock rs125,nsr150sp or tzm150, and smoked ninja 250R easily, but much cheaper.. & it's the only 2 stroke that still produced..:cry:


Hey Pugs!
Are the races you mention like the Thai drag races??
We drag-race mopped engines/bikes here in Greece too, like those races. :)
Yeah, some kind of.. check out one of the pic:)
(but still below the thai tuning level though, much longer ET for both 201 & 402 class..)


Hawweeba~!:eek5: the is equiv of getting 30hp from Mikes 100. Except his is a dedicated race bike on decent petrol & running high revs that would shorten engine life beyond what is tenable for a road bike. I hope you have a spare engine if its your daily ride.
erm sorry I'm a bit lost with the labelling of the portmap. Sub exhausts well above main?
Haha, 45+... maybe it's just me way over my head.. But it's good to have some target right?:D
Well, for daily use, I think I'm just gonna add head gasket to reduce compression and (or) retard the timing..


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

Only Kawis I've had or seen have had PVs in main & trapdoors for subs, in KX250 case I think there was 2 at different heights - but it was a long time ago & I was wondering how many of those would be still operating in 4 years time when they became trail bikes so complex was the system.
Yes, the sub exhaust port is higher than main port, with only main-port is in used when the PV closed (opposed with 2000s kx which have 2 stage pv opening: on the sub-port & the main-port). I guess it was to reduced production cost & complication by dismiss the main exhaust port valve.. With that in mind, as direction, I just raised the main port a bit (from stock at about 99* to 90* atdc), but gonna widen the sub exhaust port as much as possible to take care the blowdown needed at high rpm.. (the std height is at 84*).. Another downside is the mechanical pv controller, need to play with ball's weight/spring stiffness to change the pv opening rpm-> open the clutch cover...:facepalm:

[pugs]

Wob, an irrelevant question:
Is there any power or consumption benefit from turning the spark plug "opening" (created by the ground electrode) towards the intake?

253217

Ahm..so, I used my lame painting skills! With -tons of- imagination this could be an upside-down picture of the comb. chamber and the plug 'looking' towards the intake. The spark and the flame-front would firstly move towards the intake, starting combustion from there (?). Am I talking nonsense?:scratch:
And the proper position can be achieved by adding washers beneath the plug washer.

And oh, sorry for jumping in with irrelevant story too..
A year ago, I was experimenting singh's groove at the exhaust side of the combustion chamber..
Nice idle rpm and low rpm torque, but very-very bad idea for high rpm..
I guess the engine was overheating and detonating because of burning carbon that built there..
By coincidence, after playing with plug washer to alter the compression a bit, the deto & overheat gone magically..
Testing it further, with thinner head gasket to the upper limit of safe CR, still no deto & overheat..
It turn out that the sparkplug position that cure those combustion chamber "fault". No empirical data though...
So it must have effect for power/consumption on the nice combustion chamber too?

[husaberg]

And oh, sorry for jumping in with irrelevant story too..
A year ago, I was experimenting singh's groove at the exhaust side of the chamber..
Nice idle rpm and low rpm torque, but very-very bad idea for high rpm..
I guess the engine was overheating and detonating because of burning carbon that built there..
By coincidence, after playing with plug washer to alter the compression a bit, the deto & overheat gone magically..
Testing it further, with thinner head gasket to the upper limit of safe CR, still no deto & overheat..
It turn out that the sparkplug position that cure those combustion chamber "fault". No empirical data though...
So it must have effect for power/consumtion too?

Wob mentioned something with an advantage with the plug being proud in the combustion chamber

http://www.kiwibiker.co.nz/forums/images/BP-Brown/misc/quote_icon.png Originally Posted by wobbly http://www.kiwibiker.co.nz/forums/images/BP-Brown/buttons/viewpost-right.png (http://www.kiwibiker.co.nz/forums/showthread.php?p=1130119659#post1130119659)

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.

Although i can't remember anything with regards to orientation.

I do know that Francis Beart (Grumph will know who i mean) used to spend hours going though boxes of plugs to find one that pointed how he liked it, but he was the ultimate perfectionist.

Has anyone seen this not that i would advocate fuel injected buckets though.I found it today while looking for something else i had never come across the site before.

http://www.highgaintuning.com/product_p/gen500pfi.htm

Some of there blurb
<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if !mso]><object classid="clsid:38481807-CA0E-42D2-BF39-B33AF135CC4D" id=ieooui></object> <style> st1\:*{behavior:url(#ieooui) } </style> <![endif]--><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman";} </style> <![endif]--> In cooperated with Freescale, the largest semiconductor maker for the automotive industry, High Gain Tuning (HGT) has developed a High Performance two stroke Engine Management System (EMS) for today’s most popular 2 cycle engines used in all facets of off road and track racing Motorsports. It uses the latest Freescale 16 bit microprocessor, S12P, which combines High Performance with low cost including Freescale's latest small-engine ASIC MC33812, a highly integrated all-in-one chip, including fuel injection driver, ignition driver, voltage regulator, ISO9141, etc. The HGT 2T EFI ECU is designed to meet world-class quality standards, while remaining low cost. It performs in the harshest of hot and cold environments and is resistant to noise, vibration, corrosion and water intrusion.

This ECU offering has a compact size and is easy to install. It supports various two stroke cc displacements from 49cc to 1300cc including dual, triple and quad cylinder displacements. Its duel injector staged strategy available in the "Extreme" ECU can support engines turning up to 16,000 rpm

The HGT 2T EMS supports the following inputs and outputs :

• Engine Speed Variable Reluctant Sensors (VRS) including multi-tooth high resolution flywheels and Digital CDI inputs
• Manifold Absolute Pressure (MAP) sensor doubles as a Barometric Sensor
• Throttle Position Sensor (TPS)
• Intake air temperature sensor (IAT)
• Engine (coolant) temperature sensor (ECT)
• Vehicle speed hall-effect sensor (VSS)
• 1-4 staged injector drivers
• 1-4 ignition coil drivers
• Fuel pump relay driver
• MIL lamp driver

HGT CAL ECU software functionalities:

• Charge detection and prediction
• Fuel injection duration and timing controls
• Spark angle controls
• Fuel pump controls
• Transient fuel compensations
• Decell-fuel-cut-off
• Altitude compensations
• Temperature compensations (winter, summer, etc.)
• Engine protections
• Diagnostics and serial communications
We have also developed our own proprietary software (HGT CAL) for full engine control capabilities, including communications, diagnostics, calibrations, etc.


Also V4 2000cc two stroke
Ihad seen the end use but never wondered what powered it.
It could do with a Wobbly pipe or 4
http://twostrokemotocross.com/2009/06/2000cc-v4-two-stroke-engine/

[F5 Dave]

like the 4th pic. How can you see where you are going? Skinny tyres too.

HGT chap is on an RZ site I frequent.

[k14]

like the 4th pic. How can you see where you are going? Skinny tyres too.

HGT chap is on an RZ site I frequent.
You should have seen them at the MotoGP at Sepang. About 40 guys riding bikes like that (some scooters too) on the full gp track. Took about 4 mins to do a lap I think!

[TZ350]

The Christmas project ..... to see if we can crack 30+hp

Not quite 40 hp, as I can't get my triple port cylinder re bored over the break and probably wouldn't get a Frits pipe made in time either so its a refinement of what I have thanks to EngMod2T's help. Means gluing the transfers to reduce the trans duration and depends very much on how much I can improve the air flow through the carb.

253239

Simulated crank hp. Drop something for transmission loss and some more for workmanship and it still might be possible to crack 30+ at the rear wheel with what I already have, with any luck, 31-32.

Conventional setup, old RS pipe, Single exhaust port opening 79deg ATDC, Trans 117ATDC Inlet 145/90 and a new style of 24mm carb.

Ill post the dyno graph when its done ...

[Grumph]

TZ - you mentioned a plenum a couple of posts back....more information please. i've wondered whether the 24mm restriction could be overcome with a heimholz resonator inlet plenum....

Singh slots - I can't see any possible value in a 2 stroke application. Biggest value in a 4 stroke is creating a barrier at overlap to prevent charge loss out the exhaust. A jet of oily mixture aimed at the plug around ignition could well cause problems.

[bucketracer]

TZ - you mentioned a plenum a couple of posts back....more information please. i've wondered whether the 24mm restriction could be overcome with a heimholz resonator inlet plenum ....

253252

TeeZee's 1.2L Plenum ... 24mm carb 34mm inlet from the plenum to the crankcase ...

<iframe src="http://www.youtube.com/embed/YxiEo8cgopg" allowfullscreen="" frameborder="0" height="315" width="420"></iframe>

Old vids of the Plenum being tried out in the drive.

<iframe src="http://www.youtube.com/embed/p4ef-WUO1Qs" allowfullscreen="" frameborder="0" height="315" width="420"></iframe>

34mm inlet feeding ready to burn mixture to the crankcase, a good idea, and it worked in so much as the bike ran OK but not usefull because in the end it was not the carb that was restricting the power but insufficent blowdown time area.

TeeZee thinks that when he gets to the limit of a conventional 24mm carb he will look at the plenum again.

[wobbly]

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

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

[dinamik2t]

Wob, could you tell us the fuel type and compression ratio used along those tests? I think there must be some relevance to spark performance effects and these two factors, isn't there?


I added a legend to your image for convenience.
253255

[wobbly]

That engine was running Avgas at 15.8:1 with a bronze toroidal insert that could be rotated to index the plug.
It was modified later to over 50 Hp at 13000 and won 3 straight 125 kart titles.

[Grumph]

253252

TeeZee's 1.2L Plenum ... 24mm carb 34mm inlet from the plenum to the crankcase ...

The old "suck it and see " method ? I've got Vizard's formulas here somewhere for 4 stroke inlets - it's not simple arriving at a working inlet resonator, then you adjust on the dyno....Should be simple enough to insert packing pieces to change the volume.

[husaberg]

Grumph sent me these pics




Also V4 2000cc two stroke
Ihad seen the end use but never wondered what powered it.
It could do with a Wobbly pipe or 4
http://twostrokemotocross.com/2009/06/2000cc-v4-two-stroke-engine/

I don't know where the V4 came from that you posted but here's the Martin Jet Pack power head.
Limited I believe to around 5500 rpm to obtain sufficient life for certification to fly.
Four CR500's and ChCh built.

The engine is indeed the one and the same.

[Kickaha]

Grumph sent me these pics
I don't know where the V4 came from that you posted but here's the Martin Jet Pack power head.
Limited I believe to around 5500 rpm to obtain sufficient life for certification to fly.
Four CR500's and ChCh built.

The engine is indeed the one and the same.

Saw the bare crankcases in some blokes garage one day , I wondered what they were for

[Grumph]

Saw the bare crankcases in some blokes garage one day , I wondered what they were for

I'll bet you immediately asked if you could have one for the outfit....

[TZ350]

253330

I was looking through some links posted by Husaberg and came across this one of a performance Kart engine and was very impressed by the finning on the crankcase, it sort of suggests that case cooling should be taken seriously.

[husaberg]

I'll bet you immediately asked if you could have one for the outfit....

Which outfit? with an outfit like theses and with peanut tanks like those, Kickaha hardly needs to accessorize. Sorry Warwick beer made me do it?

[koba]

253330

I was looking through some links posted by Husanburg and came across this one of a performance Kart engine and was very impressed by the finning on the crankcase, it sort of suggests that case cooling should be taken seriously.

That reminds me of something I meant to bring up ages ago.

Have you seen the crank-case on the old Steve Roberts Aluminium Monocoque bike?

It has had a tool (Looks like a bluntened drill bit maybe) run all over it to increase the surface area.
I'll see if I can find a pic. Someone else may post one too.

May be a good trick to try on a bucket.
I dunno how much of a difference it would make. There has to be a small weight saving too.
Maybe not worth the time and effort but only one way to find out really.
I'm not sure there would be as much lee-way with meat in the cases as an old GS1000 motor though.
It would also be important not to pick up heat from the pipe (as Frits points out).

[husaberg]

That reminds me of something I meant to bring up ages ago.

Have you seen the crank-case on the old Steve Roberts Aluminium Monocoque bike?

It has had a tool (Looks like a bluntened drill bit maybe) run all over it to increase the surface area.
I'll see if I can find a pic. Someone else may post one too.

May be a good trick to try on a bucket.
I dunno how much of a difference it would make. There has to be a small weight saving too.
Maybe not worth the time and effort but only one way to find out really.
I'm not sure there would be as much lee-way with meat in the cases as an old GS1000 motor though.
It would also be important not to pick up heat from the pipe (as Frits points out).

I think what you have seen is what is called dimple drilling
It was big in the 60's commonly done on the inside of already light things like crankcase covers it would provide a small weight (and i mean small)saving on a sandcast Triumph chain-case but it would do little on a diecast cover and probably weaken them (Crack etc)

What about encasing the crankcase in paraffin Wax this absorbs an incredible amount of heat to change state from soild to liquid and again from liquid to gas.
http://autospeed.com/cms/title_The-Fusion-Intercooler/A_110772/article.html
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The obvious advantage over water/ice is it turns back to solid all by itself.

I think it has some merit in regards to crankcase cooling note there are other less common wax's that have higher melting points.


If its good enough for NASA (I would avoid their o rings though)


http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20100040644_2010043777.pdf
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110010960_2011009592.pdf
Thermal Mass

The limiting factor in such a 'closed-loop' heatsink intercooler design is the amount of heat it can absorb. In the small water/air core being used in the Mira Turbo, the thermal mass (the amount of heat able to be absorbed for a given temperature rise) was sufficient for all but the duration of boost used on long hills. And that was with only a few litres of water (and the copper tubes) for the heat storage.
Water has a very high thermal mass, or more technically, a high [I]specific heat. Think of it like this: when you place a saucepan of water on the stove it takes the input of a lot of energy before the temperature of the water changes much. (Try heating that saucepan of water with a single candle!) In fact the specific heat of water is 4.18 kilojoules per kilogram per degree C. So, to raise the temp of 1 litre of water (1 litre of water has a mass of 1kg) by one degree C requires 4.18 kilojoules of energy. As I said, that's a lot.
In fact, as a comparison, have a look at some specific heat values of common materials:

<tbody>
Material
Specific Heat
(kJ/kg/degree C)


Water
4.18


Aluminium
0.94


Copper
0.39


Air
1.01


Concrete
0.88

</tbody>



So if you were using a solid block of aluminium as your heat storage mechanism, you'd need 4.4 times the mass of aluminium to get the same heat storage as water. (As you can see, specific heat doesn't have much to do with how good a conductor the material is.)
If you want to make a heatsink that's capable of absorbing lots of heat without increasing much in temperature, you could use lots of water. For example, if the heat of the boosted intake air could be conducted to - say - 20 litres of water, I'd bet that in a road car the intake air temp on boost would never get very high. But 20 litres of water is 20kg, and because water is a poor conductor of heat, you'd also need a really good heat exchange mechanism.
Hmmm, too big and heavy.
So is there a commonly available substance with a much higher specific heat than water? The short answer is 'no'.
Doing it Differently

These sorts of questions are also being covered extensively in an industry that has nothing to do with turbocharged cars. In solar house design, adding thermal mass is important because it knocks off the highs and lows of temperature extremes that are experienced by the occupants. For example, because water has a much higher specific heat than say concrete (see table above), some designers place storage containers of water within the house. This water gradually rises in temp on the hot days (keeping the house cooler) then feeds the heat back out as the temperature drops (keeping it warmer). In short, the water containers act as heatsinks, knocking off the peaks and troughs in the temp variations.
But the same problems apply to using large bodies of water in a house as they do to a turbo engine heatsink/intercooler application-lots of water is needed if you want to absorb lots of heat. So solar house designers are exploring a completely different way of storing that heat.
[I]They are now using materials that absorb a lot of energy as they change in state.
Huh? That's it? Yes - now let's look at what that means. It is incredibly significant.
We've covered the idea that materials have a specific heat - the property of the material that determines how much heat it can absorb for a given temperature increase. But there's also another characteristic of materials, called the specific heat of fusion.
http://us1.webpublications.com.au/static/images/articles/i1107/110772_4lo.jpg
Let's have a detailed example. We'll start with a solid (rather than a liquid or a gas) which we'll call 'Performal'. We get a chunk of Performal and put it in a saucepan on the stove. We then place a thermometer probe in the Performal and turn the stove to 'high'. Every minute we take a temp reading, and as expected, the stuff starts getting warmer. It must have a pretty high specific heat, because even though the stove is set to high it warms up only slowly. In fact, the graph here shows the temp increase that we measured over the first ten minutes.

http://us1.webpublications.com.au/static/images/articles/i1107/110772_5lo.jpg
We're getting pretty bored with this experiment (what is this, a performance car magazine or a science class?!) and so when we jot down '50 degrees C' as the temp after 10 minutes we're thinking more of that night's cruise than anything else. And so when the next reading after another minute is also 50 degrees C, we get the uncomfortable feeling that we've stuffed up the readings. The stove is still running on high, pouring heat into the Performal, but a further minute later the temp of the Performal is still 50 degrees C!What the hell is going on? Have the laws of physics and chemistry gone out the window? We're continuing to add heat - lots of it - but the substance isn't getting any hotter!?
What is happening is that the Performal is melting - it is changing from a solid to a liquid at 50 degrees. And when it undergoes that change in state, it can absorb lots of energy without altering in temperature. Instead of heating the material up, the energy from the stove is being used to separate the material's molecular bonds.
Until all of the Performal has changed from a solid to a liquid, its temperature will not change. That's what the above graph shows - and you can see that the temp is being held constant, even though we're continuing to pour in the heat energy from the stove. It's only when the Performal has completely melted that its temp will start to rise again - and then the rate of temp increase will be dependent on the specific heat of Performal in liquid form, which might be different to its specific heat in solid form.
http://us1.webpublications.com.au/static/images/articles/i1107/110772_6lo.jpg
So here's a graph that showed what happened as we heated the Performal. When it started to change state, it had the capability of absorbing a huge amount of energy without getting any hotter. And the amount of energy it can absorb during this change of state is called its specific heat of fusion.

<tbody>
Some Definitions
Specific Heat - the quantity of heat required to raise the temperature of one gram of a substance by one degree Celsius.
Specific Heat of Fusion - the quantity of heat required to convert a substance from the solid to the liquid state with no temperature change.
Melting point - the temperature at which the substance changes from a solid to a liquid.

</tbody>



Back to Cars

So where does this leave us? Well, let's pack a conventional air/air intercooler core with Performal. We'll first heat the Performal up until it melts, then pour it through all the fins of the intercooler, filling them right up. After that, we'll place a water-tight jacket all round the core (so the Performal can't leak out when it melts) and then we'll insulate the assembly so that under-bonnet heat can't affect it. Finally, the new heatsink will be installed in the turbo-to-intake plumbing.
Remember, Performal has four different characteristics that interest us:


Its specific heat as a solid
Its melting point
Its specific heat of fusion
Its specific heat as a liquid

To remind you, Performal's melting point is 50 degrees C.
So, the car's cold and so you only gently drive it down the street on this 30-degree C day. But after half an hour of this gentle driving the temps have stabilised: at idle the temp of the air coming out of the turbo is 40 degrees C, and the temp of the Performal heatsink is also 40 degrees.
Then you put your foot down. The turbo spools up to 15 psi boost and the air coming out of the turbo rockets from 40 degrees to 80 degrees. But a lot of this heat is absorbed as the air passes through the aluminium and Performal honeycomb heatsink, so the intake air temp at the engine remains much cooler - say (with some heat exchange efficiency losses) it's 50 degrees C. After 5 seconds of full boost the heatsink has risen in temp to 45 degrees C, with the heat all being absorbed by the Performal's specific heat capability as a solid.
You get back off the throttle and go back to a cruise. The heat from the heatsink is now fed back into the airstream, which is now cooler than the heatsink. Effectively, the heatsink is being internally cooled.
But that five seconds of boost has whetted your appetite: this time you wind it right out through the first three gears at full boost. The temp of the heatsink rises: soon it has reached 50 degrees C and the Performal starts to change state, to melt. Its ability to absorb energy without rising higher in temp is now taking effect: despite a huge amount of heat being pumped into the heatsink, the outlet air temp stays just the same, at (say) a constant 55 degrees C. Again, when you get off the throttle and the air flowing through the heatsink is lower in temp than heatsink temp, the heat will be fed back into the intake airstream and the heatsink will cool. As it cools the Performal will start to solidify, until when it has all turned back into a solid, its temp will start to drop below 50.
The speed bug has bitten and you decide to go for a top speed run: on full boost continuously for a minute. The Performal then warms up, reaches melting point and holds the intake air temp steady. But it can only do this while the material is melting, and after 40 seconds it has all turned to a liquid. At this point, its temp will again start to rise, but even as a liquid it will be absorbing heat and so reducing the turbo outlet temp. Of course, when the police catch you and you are having a roadside discussion, that heat will be being fed back into the airstream: it is likely to stay warm for some time.

<tbody>
Ice/Water Fusion Intercooler
Drag racers who use a mixture of ice and water in a heat exchanger core are already using a fusion intercooler. The specific heat of fusion for ice (ie how much energy per kilogram is required to melt it) is 334 kJ/Kg. That's why ice/water systems are so effective - a lot of energy is required to melt the ice and the ice/water mix will stay at 0 degrees C until all of the ice is melted. Trouble is for a road car, the water doesn't turn back into ice when the car's back off boost.....

</tbody>



The Potential

You can see now why some 2700 words ago I said that for the system to be effective, the off-boost intake air temp must be below 50 degrees. Otherwise, with the normal off-boost heat the Performal would be melted all of the time, and so its capability to absorb heat during its change of state would be gone. (That is, it would already be changed in state!)
That off-boost turbo outlet temp will be dependent on a number of things:


The temp of the air being breathed by the turbo
The heating of the compressor side of the turbo by the exhaust manifold and turbine
The size and design of the turbo
The temperature of the day
The airflow through the engine bay

In areas of cold climate the off-boost turbo outlet temp is very unlikely to ever exceed 50 degrees C, however, when the ambient is 40 degrees C the air coming out of the turbo will often be above 50 even when off-boost.
http://us1.webpublications.com.au/static/images/articles/i1107/110772_7lo.jpg
I had intended fitting a Performal heatsink to my Nissan Maxima VG20DE turbo, however the transverse engine location (the turbo is heated by the radiator airflow), the very small turbo and the long intake path all conspired to give a turbo outlet temp of about 30 degrees above ambient! Since where I live the ambient seldom drops below 20, the Performal would be frequently already changed in state, even before boost hit. It's therefore not suitable for this car and climate, and it shows how important direct measurement of the actual temps really is.
(Of course, I could place a free-flowing but very small air/air intercooler in front of the Performal heatsink - this would cool the off-boost air sufficiently to keep the Performal as a solid, while the small air/air intercooler's performance on boost wouldn't matter - it would just need to flow enough air to not be a restriction. However, space constraints mean that such an approach on my car would be very difficult.)
"Performal"?

http://us1.webpublications.com.au/static/images/articles/i1107/110772_8lo.jpg
The potential on the right car is huge: but what actually is bloody "Performal"? Time to let you into a secret - and some of you may have already guessed. "Performal" doesn't exist but a substance with very similar characteristics is commonly available. It is called paraffin wax, and is sold for use in making candles. Specifically, its typical characteristics are:


Melting point: 52 degrees C
Specific heat: 3.27 kJ per kg per degree C
Specific heat of fusion: 210 kJ/kg

So to increase the temp of 1kg of the wax from 47 to 52 degrees takes 16.35kJ, but to push it past 52 degrees takes nearly 13 times as much energy. (Or, to risk causing confusion, you could dissipate in it a power of 14kW for 15 seconds to melt 1kg.)
Paraffin wax is non-toxic, doesn't explode (although it will catch fire if you expose it to a naked flame) and is easily handled. Special waxes designed specifically for this change-of-state heat storage purpose are also available with melting points in 10-degree C increments from 50 degrees to 100 degrees C, however their availability is obviously less than simple candle wax.

<tbody>
Constructing One?
http://us1.webpublications.com.au/static/images/articles/i1107/110772_9lo.jpg
The easiest approach to making a fusion intercooler would be to obtain a small air/air intercooler core, which has adequate airflow for the application. The core could be sealed with sheet aluminium welded into place, much as the water/air design shown here was constructed. The assembly could then be heated to perhaps 60 degrees C in an oven and before having its core completely filled with molten wax - but with a small gap left for expansion. The resulting assembly would then need to be insulated from underbonnet heat, perhaps by being placed in a larger box and having the gaps filled with expanding foam applied with a spray can.

</tbody>



From Here?

As I said above, the car that I had hoped to apply the technology to isn't suitable: its off-boost intake air temp is too high. However, in the past I have owned turbo cars where the off-boost intake air temp was only 5-10 degrees above ambient, and these would be suitable for the technique. Remember, this approach would not be appropriate for race cars or for cars spending long times on boost on a dyno; it would however be very suitable for turbo cars where packaging is very tight (or a rear- or mid-mounted engine is used) and where in normal road use the duration of boost is limited.
It's a fascinating concept, which as the URLs below show is now being used in other industries and applications. (To find more links do a web search under 'phase change materials heat storage' or similar.) Equipped with a wax or other phase change material that melted at (say) 65 degrees C, the fusion intercooler could even be used as a 'safety' heatsink, able to knock the top of peaks that only rarely occur, or occur for only a very short period.
Either as a main intercooler/heatsink, or as an additional safety device, it's certainly something with huge real-world potential.

[TZ350]

EngMod2T

Port STA's ... (Specific-Time-Area's)

Working out the size of the ports and port duration or timing needed for the rpm and power output I want.

253359

Choose the peak power rpm then target power output.

In the Edit-Engine-Screen click on the Target BMEP Calculate Button and you use the pop-up screen to enter the Target Power in kW or hP and it calculates the BMEP required in Bar.

253360

After entering the port dimensions in the Edit-Exhaust-Port, Edit-Transfer-Port, Edit-Inlet-Port and other basic info I can check and adjust the ports untill they achieve the STA's required.

253358

Pretty easy way of getting a development plan on target quickly .... or exploring whats possible with what I have.

[TZ350]

EngMod2T

More adventures with Engmod, I think its a great development tool and well supported, within a week or so of Neels becoming aware of some data input glitches he sent out fixes. Also an update for transferring the calculated combustion values for ignition delay, burn time and turbulence from a performance graph to the combustion data file.

These figures used to have to be calculated by the simulator then transferred by hand from a graph to the combustion file. A bit of a pain as the combustion data has to be re calculated every time there is any change in the physical combustion chamber shape, compression ratio, fuel, squish clearance, squish velocity, all stuff that affects the burn rate.

253369

The simulator is first run in Turbulent Mode using the defult combustion data settings.

253366

Turbulance

253368

Delay in getting the fire underway and burn time.

The burn time (in degrees) decreases with rpm, I guess because of increasing turbulance.

And the shape of the burn curve and delay suggests the shape of the ignition curve I could try.

253370

The new Combustion Data File can be created using this button.

253367

Easy as ..... and now I can play with the ignition Timing and AFR to see what affects changes there might have.

[wobbly]

Here is a first play with the GP125,much easyer to ride fast, and all realistic inputs.

[TZ350]

I like it, try as I might I couldn't get rid of that dip, thanks for the new file and tips ......

[TZ350]

Gigglebutton, this is a racer Cotswold peddled (Raced) in England,

I have seen two of these frames at Keith Robinsons, they looked light and strong.

253372

Giggles do you think you could make copies of them for F4 and F5 engines at an affordable price?

[husaberg]

Gigglebutton, this is a racer Cotswold peddled in England,

I have seen two of these frames at Keith Robinsons, they looked light and strong.

253372

Giggles do you think you could make copies of them for F4 and F5 engines at an affordable price?

Looks like a Waddon they did the Rotax Tandam twin as well. The forrunner to the Aprilia v twin
http://www.waddon.me/2011/01/the-waddon-frame/
Tony Foale was big on that style for a while. The frame designer Nigel Leaper used to work with him in the 70's.THe basic frame was able to accept both Yamaha and rotax 250 engines
Ask Grumph to show some of his replicas ie Machi. Grumph....... I am asking nicely.
Email them and I will post them for you if you want.
Grumph if i am not mistaken also used a novel source of steel light gauge section for the spine in his Machi replicas.:psst:

[TZ350]

A Waddon style chassis and light wire wheels like Chambers uses could be the go. The search is on for some detailed drawings and dimensions suitable for a F4 frame.

Here is a link to an interesting frame build, very detailed pictures.
http://forums.sohc4.net/index.php?PHPSESSID=1a1fc51f16b4572c4448fac65d78bc 6b&topic=44736.0
frame tubes are ST37, dimensions 28x1.5mm, 70x1.5mm, 100x1.5mm. TIG weldet. frame weight 8.5kg, swingarm 3.4kg

It has got to be possible to build Waddon style frames for F4' and 5's ...

[TZ350]

Husaburg sent me a link to a Aermacchi frame build

http://flashbackfab.com/pages/racegallery.html

253399 253402

And here is the engine build

http://flashbackfab.com/pages/builda392.html

253400 253401

Sure some might call it a dirty puff dragon but its interesting engineering never the less ........

[cotswold]

[QUOTE=husaberg;1130221442]Looks like a Waddon

That is a Waddon from 1983.

[husaberg]

Husaburg sent me a link to a Aermacchi frame build

http://flashbackfab.com/pages/racegallery.html

253399 253402

And here is the engine build

http://flashbackfab.com/pages/builda392.html

253400 253401http://www.eurospares.com/graphics.htm

Sure some might call it a dirty puff dragon but its interesting engineering never the less ........

If you want to see interesting engineering have a look at the excelsior V twin on the same site that will blow your mind someone on the thread may know some people who have contributed to that as well.
http://flashbackfab.com/pages/excel00.html



Grumph sent me some pics of his handy work and yes it is pretty handy.


Also a Tony Foale tz frame and some other random stuff from here
http://www.eurospares.com/graphics.htm

[F5 Dave]

They may be old hat & compromised, but there is just something about Astralites that appeals to me from the first time I picked one up.

[husaberg]

They may be old hat & compromised, but there is just something about Astralites that appeals to me from the first time I picked one up.

Super light and super strong 20 spokes yes count them 20!. The lightest he made in 3 inch wide was 1.8kgs for some works bike.
It was cantilevered and only achieve full strength when the tyre was inflated
The thing with these wheels is if they fail they fail slowly like a spoked wheel rather than snap like a carrot. Ask Robert Dunlop re IOM wheel collapse.
He stopped making them when the material suppler insisted he order tons of the very special material at a time. With no guarantee of the quality. Rationalization they call it.
He still makes very sexy wheels. Tony Dawson.

[Grumph]

This has turned into a good example of KB's tendency to wander off subject...should have been in the race frames thread IMO..
However, something that will resonate with a few Kiwis, Paul Brodie who features in the site linked by Husaberg, lives just outside vancouver. A few years back, returning from an AHRMA meet at Sears Point he had his van and bikes stolen at an overnight stop.
He seems to have dropped Aermacchis totally at that point and built the Excelsior as therapy.

The Waddon style spine frame is relatively easy to build. Supply your frame builder with the forks and suspension you wish to use. Possibly seat and tank also. Easy peasy...
from a frame builders point of view the hard part is getting paid.....

[husaberg]

This has turned into a good example of KB's tendency to wander off subject...should have been in the race frames thread IMO..
However, something that will resonate with a few Kiwis, Paul Brodie who features in the site linked by Husaberg, lives just outside vancouver. A few years back, returning from an AHRMA meet at Sears Point he had his van and bikes stolen at an overnight stop.
He seems to have dropped Aermacchis totally at that point and built the Excelsior as therapy.

The Waddon style spine frame is relatively easy to build. Supply your frame builder with the forks and suspension you wish to use. Possibly seat and tank also. Easy peasy...
from a frame builders point of view the hard part is getting paid.....

Ok I think this is the one Grumph means. http://www.kiwibiker.co.nz/forums/showthread.php/145224-Race-chassis
It took a bit to find it but i am a little thick.

[TZ350]

This has turned into a good example of KB's tendency to wander off subject...should have been in the race frames thread IMO....

F4 & F5 is the great frontier of DIY racing.

Virtually nothing is off topic in the ESE Bucket development thread particularly if its technically clever DIY to do with building bikes and engines or performance tuning and theory.

Looking at the frame building stuff has got me pretty interested in a spine type frame.

253414

The big question is ... could they compete for handling and weight with a Honda RS chassis?

[Grumph]

For the racing you're doing, yes a spine frame would be stiff enough and can easily be made light enough too.

BUT - given the number of readily available alloy road frames available and the low prices they're commanding not many people are going to be interested in having one - or a batch - built.

IMO you should be looking at the 50's and 80's frames - the Derbi's and Krausers - as these have more relevance to the performance levels of the motors you're using. A Derbi style spaceframe or even a Krauser/Bultaco monococque is not hard to do.

The RS125 frame is overkill for most bucket work. even here in Canty where buckets are a full - track class, the FXR chassis is more than adequate. Rim widths are getting ridiculous on buckets too...I saw Grant ramage beat most of the buckets at levels the other week on a stock FXR with stock rims and BT39's....

[cotswold]

253414

The big question is ... could they compete for handling and weight with a Honda RS chassis?[/QUOTE]

I know when I had mine it was pretty much the class lightweight which was why Ian managed such a high position in the British champs on a bike with less BHP than the MBA's that every body had back then, also they handled very well. Mine did break the weld on the bit of box section at the rear a couple of times but these days I am sure things have progressed.

[Ocean1]

Mine did break the weld on the bit of box section at the rear a couple of times but these days I am sure things have progressed.

Funny you should say that, I had similar failures on a (non-motorbike) chassis with exactly that feature years ago. I replaced the box assembly with a large lateral tube with flanges to pick up the engine/suspension mounts, ended up stiffer and lighter and had no more cracks.

[TZ350]

For the racing you're doing, yes a spine frame would be stiff enough and can easily be made light enough too.....

That's good to hear, might be an alternative to RS's then people could build themselves small light good handling bikes using a spine frame.

Av and Haydon F ran a std CBR supplied by Honda here at the last 2 hour, they ran well but it was clear that it needed more rubber to be able to realise its potential at Mt Wellington.

Weight and grip is where its at for us, BT39's don't cut it here where the emphasis is on carrying corner speed on a tight track, to run at the front, slicks are mandatory.

253420

Av peddling Chambers bike on a rainy day at Taupo, the chassis is from an FZR250 3LN fitted with light junior motard wheels, all up weight about 85KG. Although she was fast and the bike was quick enough she found the bulky FZR hard work against the RS's, something smaller and lighter with nimble handling would be better.

Although I don't have the talent to ride at the front I like to build and ride bikes that could, there is something nice about having a well developed race bike, I guess there are others that feel the same too.

Maybe those wheels and a spine frame built to RS dimensions ....

[Kickaha]

That's good to hear, might be an alternative to RS's then people could build themselves small light good handling bikes using a spine frame.
Pesonally I think there are already some other good alternatives and the RS frame is over rated, they're small cramped and hard to get the best out of, the likes of the TZR framed bikes have more room and are easier to ride although may be a bit heavier

BT39's don't cut it here where the emphasis is on carrying corner speed on a tight track, to run at the front, slicks are mandatory.
You think on a big track you don't need corner speed?

People get sucked into thinking they need all sorts of shit to run at the front, the rider is what makes the biggest difference, regardless of the frame

[speedpro]

One thing about a home made tube frame it could be built big enough for the average bucket racer to fit on. The point about the alloy framed road bikes is a good one. My FZR250 chassis is the best thing I've ever done bucket wise. The Wellington guys were the leaders in the switch to that style of chassis. Wheels have gotten wider I think primarily because you need a certain size wheel to fit the good tyres. At Mt Wgtn at least the fast guys regularly outride even the best tyres you can get, even Henk. A few of us in Auckland a long time ago used to import little sticky French TT100GP2s but RS125 size slicks are better, available, and cheapish. Plus if your rear wheel is 3.5" you can use an old front off your local friendly 600 riders bike.

[TZ350]

TZR framed bikes have more room and are easier to ride although may be a bit heavier ...

Yess I like the look of the TZR125/250 frames, they look a better bet than the FZR250


People get sucked into thinking they need all sorts of shit to run at the front, the rider is what makes the biggest difference, regardless of the frame

You are right, the rider makes the biggest difference, I don't think there was anything I couldn't haul past on the back staight at the Taupo GP but was out ridden by a large part of the field.

Andrew A was running a pretty stock FXR chassis, and he pretty much won on talent but I am pretty sure if you didn't have slicks (or race wets for the GP) you wern't running up front with Andrew and friends.

Talking with him during the day, I got the impression he can see that a combo of good rider, fast engine and purpose built race chassis would mean that slicks on a std FXR chassis and determination might not be enough, the day hasn't arrived but it could be coming.

Anyway my interest was in an affordable alternative to the fabled RS chassis for those (and myself) that can't find one but want something a little bit special and more interesting than a hacked about 250 road bike chassis. And being able to buy or make a competitive chassis for themselves will add a bit more excitment (as if it needs it) and interest to the bucket scene.

[husaberg]

Talking with him during the day, I got the impression he can see that a combo of good rider, fast engine and purpose built race chassis would mean that slicks on a std FXR chassis and determination might not be enough, the day hasn't arrived but it could be coming.

insert ominous music don.... donn donnnnnnnne. ie movie soundtrack

[TZ350]

253428

The Day is coming ......

yum yum FXR's .... one day soon a talented rider will field a fast stroker, and it could be you, the door is wide open.

[Kickaha]

253428

The Day is coming ......

yum yum FXR's yummy full tummy .... one day soon a talented rider will field a fast stroker, it could be you

:yawn::yawn::yawn::yawn:

[quallman1234]

Talking with him during the day, I got the impression he can see that a combo of good rider, fast engine and purpose built race chassis would mean that slicks on a std FXR chassis and determination might not be enough, the day hasn't arrived but it could be coming.

Its pretty damn close in wellington now.

[husaberg]

:yawn::yawn::yawn::yawn:

Are we boring you with the 2 stroke talk Kickaha
Because..... if your bored you do have the time to get that old blue chopper out of the shed paint some flames on the peanut tank put on some risers hifgway pegs and get it ready for GM street race 2012 then.
Are you there kickaha .....Kickaha.....

Its up to you to defend the GN125's honor.;)

[Kickaha]

Are we boring you with the 2 stroke talk Kickaha

Well three years after the thread was started I'm still waiting for the all conquering two strokes to show up, the worlds reserves of fossil fuel will be used up by the time they're ready to hit the track

[husaberg]

Well three years after the thread was started I'm still waiting for the all conquering two strokes to show up, the worlds reserves of fossil fuel will be used up by the time they're ready to hit the track

Oh well I admit it. As you say if the 2 strokes are truly out matched, We should then ask the MNZ to give us a little more cc to play with then. Only to even it up so its fair.
125cc 2 stroke open carb size liquid cooled, I personally don't see any harm in it.
P.S re the fossil fuel situation look at my signature I have that sussed already.

See you at Greymouth I suggest you get used to the smell of Castrol A747.Because Vanessa is happening ning ning.

Garelli to be added below I remember them for mopeds and small dirt bikes with top specs for the time in the 70's
Have a close look at the pics and read the text the first time i seen the article the other day i was taken by the fact it was a single with 4 carbs and 2 expansion cambers and Frits's FOS looking concept all this in in 1924-26.
yes it was a single but not a conventional one. Still add up the world records.

[TZ350]

Well three years after the thread was started I'm still waiting for the all conquering two strokes to show up, the worlds reserves of fossil fuel will be used up by the time they're ready to hit the track

Yes it is a bit of a race against time .....

[Kickaha]

Oh well I admit it. As you say if the 2 strokes are truly out matched, We should then ask the MNZ to give us a little more cc to play with then. Only to even it up so its fair.
Nowhere did I say they were "truly out matched" just no one seems to be able to put together a fast two stroke with a good rider/frame combo and dominate the racing as some people seem to think will happen


Yes it is a bit of a race against time .....
I reckon we'll be on electric bikes before it happens

[Yow Ling]

Maybe we will be on mobility scooters before Kickaha gets it bucket going again

[husaberg]

Nowhere did I say they were "truly out matched" just no one seems to be able to put together a fast two stroke with a good rider/frame combo and dominate the racing as some people seem to think will happen

Artistic license. But seriously the tracks for the most part are not generally HP tracks. (there are a couple of notable exclusions of course.)
I think the main reason is because the Fxr150's are now so ubiquitous that as 75 percent of the field is mounted on them and thus the number would then suggest that generally most of the fastest rider will probably be on them as well.
Also the FXR are a modern design as well they are a generation ahead of the 2 stroke engines freely available.

Its just that no manufacturer makes a serious 2 stroke liquid cooled bike case reed or disk valve power valve anymore or ever really, also no half way serious 125cc ac 2 strokes since the early 80's.
The people that have the skill to create or pay to have a genuine contender 2 stroke are pushing 40 or older with kids and responsibilities.
and are a little (lot) heavier.
I for one are going to try and stop the rot even if it means having to have someone else take up the ridding duties.

[TZ350]

Page 390 Technical Posts from the last 10 pages. There are other collections on each decade page back to page 80.

Husaberg has posted many interesting articles, the best way to find these is to use the Thread-Tools then View-Thread-Images and then sort them from the beginning and 70 a page, there are about 3,000 images on this thread.


... the BRA rules .. Bucket Racing in Australia ...



Poor 1970's commuter-bike crank... 13500 sounds like a big ask. Phenolic main brgs with RGV250 rod assembly has proved reliable so far, the RGV rod doesn’t use side washers so gets better oiling and away from the b/e seizure problem TF/TS’s often suffer from ....


I'm pretty sure if you order a TS/TF rod you will be told they have been superceded. The only genuine rod you can get that fits is what used to be the RM rod. You have to wonder why they even bothered making two rods with different material specs.


Shh ... You may find something "legal" here http://www.pro-x.com/downloads/Technical.pdf …


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

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


… I made plastic plugs several years ago using glass reinforced Peek,and tested them with no positive results at all. But now we have tripple ports reaching around to 1/2 bore, and yes they do work a treat.

Some engine development tips


Re TuBMax, this is the temp of the unburnt end gases in the squish.
It is affected only by a few factors.The main ones being ignition advance and effective compression.
Effective com is composed of the static com as set by the cc in the head. Then you add dynamic com to this.

The dynamic com increases with charging efficiency ie more air/fuel in the cylinder per stroke - better trapping efficiency ie more air fuel kept in the cylinder per stroke, and lastly scavenging efficiency - less exhaust residuals left behind per stroke.

As you increase the last three mentioned, then the effective compression within the cylinder, as the piston approaches TDC, becomes greater, and more fuel is burnt - creating more pressure and heat, thus power.

Then you will reach a stage where the end gasses detonate, due to radicals forming, from excess heat and or uncontrolled pressure rise.

The only way to reduce this, is to drop the static com or reduce the ignition lead.
As you approach the theoretical limits of charging, trapping and scavenging efficiency, then you have to balance this with a static com and or ignition advance that will keep the piston alive.

This is exactly what happens on the dyno during development - its a juggling act to balance the com and advance to get the highest cylinder pressure you can, to release as much heat into the gas as is possible ,at the right time to suit the engine characteristics needed.

Com and advance put more of the finite fuel "energy" into the piston and cylinder and then eventually into the water - thus this energy is lost, and cannot be used in the external sense ie to heat up the pipe and generate more overev .

But pushing the limits of all the factors, in some form of synergy, is the black art we are only just beginning to be able to reliably juggle with in a good sim - without locking up a piston and a rod coming at you thru the screen.

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


… we need to address two important factors in a 2T engine design.
Torque and rpm it all comes down to Hp = Tq*RPM/5252.

Keep the torque constant and increase rpm by 10% and you get 10% more power.
Hard part is holding up the torque at the higher rpm level.

A short stroke will allow greater safe rpm, but the bore area needed to create the angle area needed, is limited more and more as you increase the piston size at the expense of stroke length.
The piston gets heavier as well, so ultimately the engine may not physically be able to rev to anything like what the stroke may allow.

The bottom line to all this is that the square engine has the best compromises of rpm capability Vs useful bore area.

Go short stroke and though you may be able to rev it, the scavenging is compromised by the bore availability. With long stroke - the reverse happens.

This all assumes we are talking max power capability - 250cc MX is all longer stroke now as this favours torque production from low rpms, and the extra rpm capability of a square engine isn’t needed to create peak power numbers.


The stinger config in pipe 21 is exactly what is needed for a 125 making anything like 50 Hp.

253507

I have been using CNC nozzles I had made over 10 years ago that are 23.2 at the smallest section specifically for the pipes I have built for karts that make around 50.

For a 125 down at 40 Hp then 22 is about right, as is used by the CR125 engines in SKUSA stock class,down at 30 Hp I would say 20 or 21 ( never built one, sorry)

It all comes down to the amount of air that is dumped into the pipe, and this is totally reflected in the Hp numbers - empirically these sizes work every time to generate the correct back pressure, without causing deto or finicky tuning issues.


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

253509




NGK race plugs were originally designed to be about 1mm proud of the chamber,one reason there are no threads on the shell end.

This leads on to one reason that a toroidal chamber design works best.
I believe that plug position and indexing effects are reduced considerably by the quality of the CDI and the energy in the gap.

Using Ignitech and 0.2 Ohm primary Aprilia RS250 ( RGV) coils, I tested plug indexing and found no difference - but the fine wire R7376-10 plug made near on 2 Hp in 50 against a
Denso RS125 plug and a B10EGV.

253508




That engine was running Avgas at 15.8:1 with a bronze toroidal insert that could be rotated to index the plug.
It was modified later to over 50 Hp at 13000 and won 3 straight 125 kart titles.


I was looking through some links posted by Husaberg and came across this one of a performance Kart engine and was very impressed by the finning on the crankcase, it sort of suggests that case cooling should be taken seriously.

253506



A very informative post on specific heat ….. its worth a read.



Specific Heat - the quantity of heat required to raise the temperature of one gram of a substance by one degree Celsius.
Specific Heat of Fusion - the quantity of heat required to convert a substance from the solid to the liquid state with no temperature change.
Melting point - the temperature at which the substance changes from a solid to a liquid.

* Its specific heat as a solid
* Its melting point
* Its specific heat of fusion
* Its specific heat as a liquid

[TZ350]

Simulation for Husaburg to see if the simulator will show him any performance advantage with using a positive offset.

253491

253467

+5mm offset, not much in it. will try 12 forward next.

253475

+12mm offset

Its negative offset or backwards compaired to crank rotation to reduce noise and positive for performance. The simulator doesn't see much in it. But it did affect the combustion chamber volume for correct compression ratio.

My experiance with wrist pin/cylinder offset as an engine re-building industry insider back in the day was that offset was in the negative direction, and about 2mm or so and was the manufacturers attempt to quietin piston slap as the crank passes through TDC. Get off set pistons the wrong way around in a reco engine and the engine became very noisy.

A bit of time on the net and you can find out all sorts of things.

253468


More than anyone ever wanted to know about offset
http://homepages.cae.wisc.edu/~hessel/faqs/kiva4faqs/zpistnCalculationWAndWOWristpinOffset.html (http://homepages.cae.wisc.edu/%7Ehessel/faqs/kiva4faqs/zpistnCalculationWAndWOWristpinOffset.html)


Taken from
http://www.network54.com/Forum/74182/thread/1286357572/1286438278/Offset+vs.symmetrical+piston+pin+-+any+real+difference-


(http://www.network54.com/Forum/74182/thread/1286357572/1286438278/Offset+vs.symmetrical+piston+pin+-+any+real+difference-)
<tbody>
Right, there was a noticeable difference. Some NASCAR racers were disqualified when.....


October 6 2010, 10:12 AM

</tbody>


<tbody>
it was found upon teardown that they had reversed the pistons. Here's what the racers discovered. The factory installed offset was against the direction of rotation which quieted the piston slap noise. But performance suffered because the angle on the rod is increased even more than on a piston with an on center pin. More of the combustion pressure is wasted trying to get over center and pushing the rod "sideways" instead of down. So turning the piston 180 degrees puts the rod and pin at the same angle of offset, but in the direction of rotation. This gives the rod a more downward or straight orientation so that the combustion pressure is not wasted trying to get over center, but is used to push downward.

This is the the same as the "long rod" principle. The geometry is reconfigured in a different manner than modifying the offset, but the end result is the same; the rod is straighter in the bore at any given degree of rotation.

There are a couple more ways of doing the same thing. One is offset overboring in the direction of rotation. The other is casting the crank centerline in the block so that it does NOT intersect the cylinder bore centerlines. Example: the FH V8 cranks were .265" offcenter in the direction of rotation. An FH upside down on a stand really looks strange because the offset is very noticeable. And when it is rightside up and you turn the the crank you notice that as you turn the crank the piston comes up slowly on the upstroke but drops off quickly on the downstroke. This is the same thing that happens when you reverse and offset piston to the direction.

The illustration I always use is the bicycle crank. You remember how hard it was to get you bike going when you tried to push the pedal the closer it was to top dead center. So you would keep pressure on the pedal with one foot while you pushed the bike forward a little with the other foot to get a better or more downward angle on the pedal. Same thing with pin offset in the direction of rotation.

So in other words, the standard placement of the offset piston pin against the direction of rotation hurts performance.

Hollis Franks
Black 63 1/2 XL R Code
Gray 65 289 Falcon Ranchero




</tbody>

[F5 Dave]

I seriously think a fit Nigel on a long track would just make the whole argument mute. Actually I wonder when Bren will do the same duwn sowth.

[jasonu]

I seriously think a fit Nigel on a long track would just make the whole argument mute. Actually I wonder when Bren will do the same duwn sowth.

He will have to address the reliability issues first.

[TZ350]

... I've got Vizard's formulas here somewhere for 4 stroke inlets - it's not simple arriving at a working inlet resonator, then you adjust on the dyno ...

I would be very interested in any numbers you can come up with.

[Fast Eddie]

Nowhere did I say they were "truly out matched" just no one seems to be able to put together a fast two stroke with a good rider/frame combo and dominate the racing as some people seem to think will happen


I reckon we'll be on electric bikes before it happens

hoping to race my 2 stroke thing in the garage I'm building up (when I get some replacement parts). I didn't think there was any real class I could race in though? f3 or whatever with the 400cc 4t's?

merry xmas too.

[Grumph]

When Vizard was here some years back he did a seminar for the Engine reconditioning assn in ChCh - fortunately it was an open seminar.

He was frank about inlet resonators - he didn't have the answers yet. the formulas he gave were guides at best and worked on large 4 strokes. Remember, as he said - 70% of all race engines in the world are Chevy based V8's....that's where he earns his $$$.

A maximum of 4 cylinders per plenum - volume for 4 cyl 50 -60% of the volume of all 4. 3 cylinders 65 - 80% of the volume of all 3.
Two cylinders - about equal to the volume of both.

RPM range - lower rpm = bigger plenum volume. Higher rpm = smaller volume.

[TZ350]

Thanks Grumph ...


Two cylinders - about equal to the volume of both.

RPM range - lower rpm = bigger plenum volume. Higher rpm = smaller volume.

If two 4-stroke cly - about equal to the volume of both

Then would a single 2-stroke cly - the volume of itself? sounds like my 125's plenum at 1.2l may be way to big.

[TZ350]

Hi Husaberg

253523

here is a simulation with plus 12 and minus 12mm offset at the pin, you may get the same results by moving the cylinder.

[Grumph]

Sorry TZ that was only part of my original attempt post...

Volume within limits is not critical as he says the length of the inlet tract into the resonator can be varied on the dyno to change the system frequency hence torque peak rpm.
He says don't exceed 180 ft/min on the intake velocity into the plenum - doubt you'd exceed that with a 24mm carb on a 125.

Given the shape of your existing plenum TZ, flow lines could be a problem with making it smaller.

There's got to be more up to date info somewhere on the web - even if it's 4 stroke based the principles are the same

[TZ350]

There's got to be more up to date info somewhere on the web - even if it's 4 stroke based the principles are the same

Thanks, and yes, even if its 4-stroke it gives me the idea and I can halve or double the numbers to find a 2-stroke solution.

[TZ350]

More for Husaberg

253546 253545

Differences in combustion chamber volume for the same corrected compression ratio.

253544 253547

Plus 12mm Minus 12mm STA's

EngMod2T is very usefull and only $400 USD to buy, everyone should have a copy ....

[NordieBoy]

Anyone got anything that'll convert old Auto Sketch SKD files into something useful?

[Grumph]

[QUOTE=TZ350

EngMod2T is very usefull and only $400 USD to buy, everyone should have a copy ....[/QUOTE]

Won't be long before everyone is racing simulator programmes anyway.....cheaper than actually building something.

[TZ350]

Won't be long before everyone is racing simulator programmes anyway.....cheaper than actually building something.

Lot less noisy than a real dyno too .... :laugh:

[TZ350]

Ok .... this is where the simulated rubber hits the road.

We are going to see if we can make this.

Bearing in mind this is simulated crankshaft hp that assumes an expertly made motor and that the DynoJet dyno we use graphs rwhp and there will be some differences because of transmission losses and workmanship.

253550

Red line is my efforts with EngMod2T, Blue line is after Wobbly polished it up a bit and replaced the RS pipe with one of his own design.

First off is to fit a degree wheel.

253552

and set the deck-hight and squish clearance

253551

then zero the degree wheel

253554

The transfer timings

253555

and transfer port angles

253553

the exhaust port data, Ex opens 78.5deg ATDC, 0.5 deg now thats pretty exacting.

I will have a measure up and see what I have got then its off to the workshop for a bit of porting fun.

[NordieBoy]

Lot less noisy than a real dyno too .... :laugh:

Cheaper to race 2-strokes too, no need to get a sub-woofer.

[TZ350]

Measuring what I have.

253559

A trick suggested to me by Speedpro is to use a piece of lockwire flattened on the end to feel for the port opening.

Mine finished up 0.5mm thick, so I raised the barrel 0.5mm and in theory what I read on the degree wheel and the port timing the motor sees when its all put together and running will be the same thing.

253560

Finding the transfer opening points.

253556

118.5 deg ATDC, Wobbly wants 116 for the main and 117.2 for the other two, so close and fortunatly the roof angles are already close too so not much work needed there.

253557

A look at the Exhaust

253558

Looking for 78.5 deg ATDC, and its way out at 86.5, so plenty to do here.

Remember you cant just copy these timing's because its all about STA or specific time area and is peculiar to your target RPM and Power output.

But Wobblys rule of thumb is, low and wide for the transfers to maximise blowdown time area which is usually in short supply on a single exhaust port cylinder like mine and if you have multiple exhaust ports Low and Wide allows a low exhaust port which helps keep the pipe in resonance for longer (wider power spread).

[TZ350]

Cheaper to race 2-strokes too, no need to get a sub-woofer.

Yes ... screeeechi tweeters are cheaper .... :yes:

if we could get incense candles with the 2-stroke smell too we would be made.

[NordieBoy]

Yes ... screeeechi tweeters are cheaper .... :yes:

if we could get incense candles with the 2-stroke smell too we would be made.

Castrol candles :D

[TZ350]

Porting tools

253572

Ok ... ported the exhaust port.

Slipped a bit and garked around the transfer, thank goodness for steel putty.

253569

I was able to clean up most of the damage around the exhaust port that happened a while back when a peg came out and allowed the ring to turn and catch in the port.

253571

The barrel is 0.5mm higher because of the lock wire feeler I was using to find the port opening point.

253568

Even curve on the port roof.

253570

Thats as close to the ex opening at 78.5 deg ATDC that I can manage.

[TZ350]

253573

Next move is the inlet

253574

Fortunatly most of the work has already been done.

253575

Now to setup the compression ratio.

253577

Basic info

253576

With the ex opening 78.5 deg ATDC a combustion chamber volume of 8.976 or 9cc is required for a 7.4:1 corrected comp ratio.

253578

Small plastic syringes 3-5-10cc can be brought from the Chemist for $2-3 each, I use a 5cc syringe and anti freeze to measure the combustion chamber volume.

[Yow Ling]

As yesterday was Christmas and nothing to do, I had a cylinder to rebore and hone for a friend.
the cylinder was rg400 stock size 50.0 boring to 50.50 plus some clearence so 50.565
All went well and the finished size was honed to 50.56 which in the old money would be .0025" over

I was having a look at some Kart site about honing and they go a few steps further than I did

They bolt torque plates onto the cylinders and leave them for a few hours to let the cylinder distort
bolt an old header pipe and inlet stuff if applicable, and some hone the cylinder hot at about 350° F

http://www.ekartingnews.com/viewtopic.php?t=25643&postdays=0&postorder=asc&start=0

how much are these details worth in hp or reliability, does this allow for tighter clearances ?

Im interested as lately we have talked about the science and simulation and TZs post above reminded me that eventually this stuff needs to be cut into metal as TZ commented earlier "take off some for gearbox losses and some for workmanship" Is this the workmanship we are talking about?

[TZ350]

I was having a look at some Kart site about honing and they go a few steps further than I did

They bolt torque plates onto the cylinders and leave them for a few hours to let the cylinder distort

http://www.ekartingnews.com/viewtopic.php?t=25643&postdays=0&postorder=asc&start=0

how much are these details worth in hp or reliability, does this allow for tighter clearances ?

I like the idea of torqe plates but how much are they worth in hp and reliability? ... I have no idea and I wasn't planning on going to that much trouble myself and expect that a lot of other things have to be got right first before using torqe plates on the final hone job would make much of a differance.

But the talk of how to go about a good finishing hone job, four stones, truing sleeve, stone wear and using that to advantage, it brought back memory’s, I could smell the cutting oil.

What I do know is, that cleaning is important, after washing the cylinder in a cleaning bath and rinsing off, the cylinder wall needs to be scrubbed with a stiff brush (a tooth brush will do for a 50mm bore) and hot water and dish wash.

It needs to be scrubbed vigorously to free the carborundum particles from the hone groves. Then it needs to be rinsed off in hot water and blow dried.

You will know that its been cleaned properly if, as the cylinder dries you see a light yellow stain appear (rust) which will disappear when you oil it.

If you don’t see that stain then it hasn’t been cleaned properly and the carborundum left by the hone stones will cause premature wear of the top ring land and bore.

Just washing in a cleaning bath is not good enough for long life and reliability.

[Grumph]

Torque plates are always a good idea - the aim of course is to finish up with as perfectly round a bore as possible.

Heating the job depends on the cylinder fastening arrangements. TZ750 blocks when set up with torque plates and heated developed a measurable bulge alongside each through stud....things have got better since but if you're working with an iron liner and through studs it's worth having a look at the cylinder hot.

[TZ350]

Torque plates are always a good idea - the aim of course is to finish up with as perfectly round a bore as possible.

I made a set when I was racing a Suzuki T250 fitted with RD350 cylinders for rebores and honing but never thought to measure them hot.

I wasn't planning on going to that much trouble this time, we have been very slopy with our cylinders but your right they are a good idea especialy for our GP cylinders that have through studs, cylinders like RG400's and RGV250's that don't have through studs may not have the same problems with crush distortion but bolting a dummy head and base wouldn't do any harm.

[TZ350]

I was having a look at some Kart site about honing and they go a few steps further than I did. They bolt torque plates onto the cylinders and leave them for a few hours to let the cylinder distort.
http://www.ekartingnews.com/viewtopic.php?t=25643&postdays=0&postorder=asc&start=0
Is this the workmanship we are talking about?

No ... but I guess its another item on the list. I was thinking about more ordinary things like getting the transfers staggered just like Wobbly wants and the port entry windows in the correct ratio of 1.3 -1.2 and 1.1, and curved nicely. The inlet system the correct length and shape without humps and bumps and the workmanship for making a first class expansion chamber and all those imperfections that creep in, just basic stuff.

[Ocean1]

how much are these details worth in hp or reliability, does this allow for tighter clearances ?

Used to be standard practice for small block Chevs, the block casting was very thin walled and bolting up a solid 2" plate dummy head simulated the finished assembly. The siamesed centre bores on the 400s were particularly bendy, think there's only 1/8" between them...

I know a guy who even went to the trouble of putting the block in a powder coating oven for several heat cycles.

[TZ350]

Torque plates are always a good idea -

I can see torqe plates and a decent hone for our GP cylinders going on the to do list.

[Ocean1]

cylinders like RG400's and RGV250's that don't have through studs may not have the same problems with crush distortion but bolting a dummy head and base wouldn't do any harm.

Think it's even more gooder idea where there's bolts threaded into the cylinder, you've got the axial distortion from friction in the thread, it forces a sine wave shape into the cylinder wall. In those cases it used to be said you should use the same bolts too, and that the blanking flange be the same thickness as the head, (the distortion in the cylinder wall changes depending on how long the bolts are). Where there's a bolt hole used as an oil gallery I've even gone to the extent of using the old copper washers under the bolt head.

[TZ350]

I guess if we are aiming to push the performance level of Buckets up a notch then we need to adopt better workshop practices too ... suits me. :)

[Ocean1]

I guess if we are aiming to push the performance level of Buckets up a notch then we need to adopt better workshop practices too ... suits me. :)

Be nice to think modern FEA systems would allow designers to eliminate such quirks, but almost everything is a compromise, and if you had enough mass in the cylinder to effectively eliminate distortion it'd weigh far more than is nescessary to do it's primary job.

Machining a cylinder with a blanking plate may be even more important in a modern engine elevated to competition spec's, chrome rings and cylinders don't have anywhere near the dimensional run-in allowances the old iron jobs did.

[husaberg]

Fits/Wob can you spell out if there is any real tangible advantages with offsetting the cylinder to achieve Asymmetrical timing.

Also can anyone figure out how the Garelli engine was a split single cause it seems a little odd with 2 x exhausts. As all the other split singles i have sees have one pumping cylinder. The second pictures exhausts were getting close to expansion chambers in my opinion, because even the traditional fishtails of the era stopped a lot short of these.
The singers my need a little work though:D

[Frits Overmars]

Fits/Wob can you spell out if there is any real tangible advantages with offsetting the cylinder to achieve Asymmetrical timing.
Also can anyone figure out how the Garelli engine was a split single cause it seems a little odd with 2 x exhausts. As all the other split singles i have sees have one pumping cylinder. The second pictures exhausts were getting close to expansion chambers in my opinion, because even the traditional fishtails of the era stopped a lot short of these. The singers my need a little work though:DIf I remember correctly (1926 is some time back) the Garelli 350 Competizione was a split single allright, but unlike the later DKW split-single racers it did not have forked or articulated conrods. The Garelli was a normal 360° (both pistons rising and falling simultaneously) parallel twin with three transfer ports in the left cylinder and two exhaust ports in the right cylinder. Both cylinders shared a common combustion chamber. Each piston commanded two carburetters. Also unlike the DKWs, the Garelli had no auxiliary pump cylinder or blower of any kind.
I do like the look of the Garelli's exhaust pipes. It is the oldest bike I know of with such modern-looking pipes. Using diffusers to promote suction was not yet common practice then, and adding end cones would be regarded as revolutionary 26 years later! But I suspect that neither the exhaust timing nor the blowdown time.area of the Garelli did the end cones much justice; they were probably shaped like this just to accomodate the fish-tails.

I would not bother with offsetting cylinders or piston pins to achieve asymmetrical timing. The effect is very small and who needs the complication.
The pic below shows a calculation I did on the Aprilia RSA125. I gave it an offset of no less than 10% of the stroke in order to enhance the effect.
It is obvious that the maximum conrod angles become asymmetric. What may be less obvious, is the increase in piston stroke for a given crankshaft stroke!
It is also remarkable that it takes more than 180 crank degrees from TDC to BDC, and less than 180° from BDC to TDC.

[Grumph]

The Garelli is a real oddball split single. Most are tandem cylinders with either two rods or a forked rod. the garelli is side by side with a very long gudgeon pin. You're looking at the right hand cylinder which has the inlet ports at the bottom and two exhausts - one at the front of the cylinder and one at the back. No problems doing that as the transfers are all in the other cylinder.

So - sucks in on the right hand pot, transfers in the left hand one from a common crankcase , common combustion chamber , exhausts from the right hand pot as it's transferring fresh mix up the left barrel.....

Wob would approve of the long blowdown possible - and the uncontaminated fresh charge.

Frits - I see we overlapped - no factual differences which is pleasing - and no, I'm not old enough either.

[Grumph]

Cylinder offset - either deliberae or accidental can have some funny consequences...

When Hans von Marwitz (spelling sorry) as FIM observer measured the Britten after the world record setting runs here in Canty, he noted that the cylinders on the motor used had different strokes....didn't suprise some of us here.

60 degree V twin with a single pin crank - and a certain amount of machining error...

[Ivan]

since everyone reads this how many mm of front travel are you guys needing and what weight oil trying to sit here andfigure out a new front end for my build but want to know how much travel im going to need first was thinking 20w oil would be abit hard but should slow the front end dive down under braking and reduce the ammount of travel the bike would use

[TZ350]

Ivan what your asking is like asking for a pre arranged script that’s guarantied to chat up a girl, it doesn't work, you have to play it as you find it.

Engines on the other hand pretty much follow a formula, frames suspension and handling is something else.

For what its worth my bike is about 98kg with gas, and 200kg with rider aboard. It has 100mm of travel at the front(shortened from 120), taper roller head brgs, 150mm travel at the rear, emulators to control dive and 5wt oil in reconditioned forks, the rear shock is from a 2007 GSXR600 with compression and rebound adjustment fitted with the original spring from my FZR 3LN frame. The front chatters ever so slightly when pushed and the back tyre shows signs of the rear suspension not being complient enough so I expect it can be improved.

I have not put much time into sorting it out but expect that with some effort and experiance from playing with setups it will become a good ride.

[Ivan]

Ivan what your asking is like asking for a pre arranged script that’s guarantied to chat up a girl, it doesn't work, you have to play it as you find it.

Engines on the other hand pretty much follow a formula, frames suspension and handling is something else.

Yes I know that but im wondering what people are roughly getting in there travel so I can work out roughly how much im going to need its going to vary of course like I knowhow much we are getting on a 675 daytona but the travel is going to be a shit load more in that due to the speed and sudden loss of it under brakes were as on a bucket the speeds are not as high so the braking down force will not be as much,


I was thinking somewere around 100mm of travel would work

[Henk]

Ivan, you may be surprised at how hard you can brake on a bucket, accidental rolling stoppies aren't unusual. I'd be looking at whatever travel the bike you are basing your frame on has and try for something close to that.

[TZ350]

on a bucket the speeds are not as high so the braking down force will not be as much, I was thinking somewere around 100mm of travel would work

100mm is what we use, but there is more to it than just fork travel.

Check the physics on kinetic energy, wether the object is big or small, fast or slow its the rate of change that’s important. For instance it takes a lot of force to stop a light thing quickly, stand in the way of your average bullet to see what I mean.

Under heavy brakes (rapid rate of change) you want to control the rate of (amount of time for) weight transfer to the front wheel, regardless of actual suspension travel. As sloppy springs take to much time, and with hydrolicly locked compression dampining it happens too fast.

Fork emulators do this better than plane old compression dampening holes in the inner fork tube. If the compression dampening is to high then the forks lock and the back wheel tends to lift of the ground as the whole shebang tries to rotate around the front axel.

Compression dampening holes are always a compromise, usually what’s good for comfortable riding becomes to harsh for hard braking, but fork emulators when set up properly for the bike adjust to the damping demand.

And fork travel is more about the size of the bump you expect to negotiate, not the rate of weight transfer to the front.

And under brakes the spring rate will be about how much weight has to be supported by the suspension and still have some movement left.

So this is how I think it plays out under brakes.

Spring Rate ... is about how much weight needs to be supported and still have some suspension left for small bumps.
Fork Travel ... is about the size of the bump and movement needed to compress the spring (see Spring rate).
Compression Damping ... is about the time it takes to transfer weight to the front wheel. (not to fast, not to slow).

[Ivan]

100mm is what we use, but there is more to it than just fork travel.

Check the physics on kinetic energy, its the rate of change that’s important, wether the object is big or small, fast or slow. It takes a lot of force to stop a light thing quickly, stand in the way of your average bullet to see what I mean.

Under heavy brakes (rapid rate of change) you want to control the rate of weight transfer to the front wheel, regardless of actual suspension travel.

I think Fork emulators do this better than plane old compression dampening holes in the inner fork tube. If the compression dampening is to high then the back wheel tends to lift of the ground as the whole shebang tries to rotate around the front axel.

Compression dampening holes are always a compromise, usually what’s good for comfortable riding becomes to harsh for hard braking, but fork emulators when set up properly for the bike adjust to the damping demand.

Fork travel is more about the size of the bump you expect to negotiate, not the rate of weight transfer to the front.

And under brakes the spring rate will be more about how much weight has to be supported by the suspension and still have some movement left.

I think this is how it plays out under brakes.

Spring Rate ... is about how much weight needs to be supported and still have some suspension left for small bumps.
Fork Travel ... is about the size of the bump and movement needed to compress the spring (see Spring rate).
Compression Damping ... is about weight transfer to the front wheel.

Yip I thought 100mm would be right I might look into making my own emulator setup but wont be buying any for it I think Glen had said he changed the sized of his damper rod holes on his bucket and it handled like a dream when i rode it

[bucketracer]

Yip I thought 100mm would be right I might look into making my own emulator setup but wont be buying any --

Making your own, your a true Buckateer.

The ones you buy look fancy but I am sure with some carefull work you could make something that works just as well. TeeZee recons, if your making your own, something made of steel and welded to the top of the damper rod would be better than the store brought ones that just float on top.

[Bert]

Making your own, your a true Buckateer.

The ones you buy look fancy but I am sure with some carefull work you could make something that works just as well. TeeZee recons, if your making your own, something made of steel and welded to the top of the damper rod would be better than the store brought ones that just float on top.

I'm sure I posted up a link to an old Norton/AJS Race emulator built here in NZ (post link when found again..) it actually showed all the dimensions if I recall correctly.

but here is the theory behind them (this really suits the type of forks we all use):
http://www.racetech.com/HTML_FILES/VINTAGETHEORY.HTML

or for $85 USD:
http://www.ebay.com/itm/Front-Fork-Damper-Valve-mini-roadrace-kx65-road-racing-/360380887677?pt=Motorcycles_Parts_Accessories&vxp=mtr&hash=item53e85ff27d


this post isn't designed to stir-up discussion by NZ suppliers on their product being better as in other threads, please..


Gearing Calculator (this is quite cool for those that can't find the ratios):
http://www.gearingcommander.com/

[wobbly]

Here is a first shot at the GP125 with triple Ex ports Vs the single port version.
The single port has alot higher Ex timing and I thought that the 3 port would give better spread, if I lowered the timings and reduced the STA a bit.
It did , but lost alot of overall power in the process.
Both are using the same pipe,but the lower port in the 3Ex version lets it rev on better.
You can see the big jump in blowdown pressure entering the transfers of the single port engine when in the overev region.
Niether files are fully optimised, but are getting close.

[TZ350]

Wob, thanks for looking at my EngMod2T files.

253833

It will take me a bit of time to make a pipe to your design but I am close to trying the single port setup you have suggested using my old RS pipe.

I am not sure what I should allow for losses, I have used -12% on the RS graph and get 32 rwhp. I should get a chance to put it on the dyno in the next day or so, so fingers crossed and we will see how it works out.

[TZ350]

253839

Here is a first shot at the GP125 with triple Ex ports Vs the single port version.

Yes ... I found much the same, the triple port was not much better than the single when they both had to suck through a 24mm carb but when a biger carb was simulated the tripple produced more power up top and significantly more drive down low.

If they are both limited to a 24mm carb and similar power curves, then a good reason for making a tripple port cylinder would be for mechanical reliability with the triples main ex port width at 62% of bore diameter instead of the singles 75%.

[Yow Ling]

So if the 24mm carb is a problem where does to 100cc engine with unlimited carb sit
Apart from the water cooling is the 25cc penatly worth it?

Would it be really difficult to input the gp100 barrel into your engmod and compare it with a similarly ported 125 barrel with the different carbs

I realise that Speedpros engine is around 30hp and TZs is around the same but they are quite different motors

[Buckets4Me]

So if the 24mm carb is a problem when does the PLENUM! come back


there fixed it for ya :laugh:

[TZ350]

So if the 24mm carb is a problem where does to 100cc engine with unlimited carb sit Apart from the water cooling is the 25cc penatly worth it?

253844 Red-Speedpros 100cc engine Green-TeeZee 125cc

Yes I think it is, when chasing Speedpro at Taupo the better low down drive felt like an advantage coming off the sweeper.

[jasonu]

since everyone reads this how many mm of front travel are you guys needing and what weight oil trying to sit here andfigure out a new front end for my build but want to know how much travel im going to need first was thinking 20w oil would be abit hard but should slow the front end dive down under braking and reduce the ammount of travel the bike would use

Why don't you measure the travel of your NX4 RS125 forks? Since you are copying the frame I would have thought that might be a good place to start.
FYI my 1995 RS125 forks have 135mm of travel.

[Ivan]

i did look at that but thought since they are cartridge usd forks everything would be totally differnt hence why I asked considering most guys run conventional forks


Sorry for the thread Hi Jack back to were you were!

[TZ350]

Striped the engine down today after the Taupo GP

253861

I was having trouble in practice, the bike just did not run right, Andrew A suggested a windbreak in front of the carb and when I get a chance, to fit a still air box, the windbreak worked a treat.

253862253863253864

The head and cylinder look OK but look like they have been a bit hot and the front engine stay has cracked through.

253860

The power started to go soft and I thought it was that heat fade aircooled engines suffer from. But when I got the barrel off I found the ring had become jamed in the piston on one side. I am not sure whats caused this, its as if the area around the ring land has become swollen and partialy siezed??? Its a piston from a water cooled engine, maybe the cam and taper aren't suited to air cooled duty.

Hopefully get this sorted tommorow, free the ring up and give the piston a bit of a buzz around the ring land, fit the new cylinder and then its up onto the dyno after I dig the dyno out from under a big pile of stuff.

253886

Yep ... its under that lot somewhere .....

[husaberg]

Not written by Alan Cathcart either.
I finally figured wh he used be able to Blag so many exotic bikes the other day. Not just because never never said any thing bad about a bike either.
It turns out he went to all the factories in Italy when he started out writing features. He also, as it turns out had a fairy major advantage over most of the rest of us. He spoke fluent Italian.

[Pumba]

Just for a wind up, was reviewing a few old threads.


Its been a long time since a 4 stroke won a F4 GP so 4 stroke riders should cherish last Saturday, it might not happen again for a while.

Date was 2008

[husaberg]

Just for a wind up, was reviewing a few old threads.



Date was 2008

In response to your wind up.

What year did they bring in the 155cc rule? and what year did they bring in the 140cc rule?
Maybe the two stroke may need some more capacity as well? Or larger control carbs?

[Kickaha]

Maybe the two stroke may need some more capacity as well? Or larger control carbs?

With 30HP two strokes appearing we know neither of those is neccesary, they just need to be able to finish races

[koba]

With 30HP two strokes appearing we know neither of those is neccesary, they just need to be able to finish races

I agree, I'm happy with my chances with the plans I have. Just need another ten years to get them sorted.

[koba]

The Roberts Aluminium bike was at Wanganui and I managed to bleg Henks camera as we were having a nosey.

Here is a pic of the dimpling I was talking about.
Again I say, I'm not sure how useful it would be; just a thought.

253899

[husaberg]

You may recall Fits had a go at interpreting the Matt Oaxley interview which was in English witch was translated into either spanish or Itailian over the top I can't remember which. Well here is the Test .Strangely it is in Water injection spec. It has the water cooling radiator in the nose and slot for it. Yet the blub says it indeed as everyone (bar a few Me included ) uses about 3.5 liters per GP. So the puzzle remains.

Did Benson ever get back to your email Wob?

[TZ350]

Just for a wind up, was reviewing a few old threads.


Its been a long time since a 4 stroke won a F4 GP so 4 stroke riders should cherish last Saturday, it might not happen again for a while.

Date was 2008

......... :facepalm: on no I was wrong ..... :laugh:


With 30HP two strokes appearing we know ... they just need to be able to finish races

Big carbs I can do without, :bleh: but water cooling ....... now that would be fair ... :confused:

[Kickaha]

Just need another ten years to get them sorted.
Whoa slow down a bit, you don't want to rush like that

[TZ350]

253902

The transfer specs call for a area ratio between transfer port window and tract entry of 1.3:1 (main transfer).

253901

The tripple port cylinder on the right has had the duct entry closed up to a ratio of 1.3, it looks very small to me but the inner radius has a better looking curve to it.

[husaberg]

The Roberts Aluminium bike was at Wanganui and I managed to bleg Henks camera as we were having a nosey.

Here is a pic of the dimpling I was talking about.
Again I say, I'm not sure how useful it would be; just a thought.

253899

You could ask Steve
I think he built the BMS 851 based bike chassis as well?
Here is a article I have on worshiping, the sometimes false (esp if overdone god) of Speed Lightness.
It is an enjoyable read. The water buffalo bit is hilarious to me. Plus the magnesium axle why not. Ha ha
I note that this example of dimple drilling above maybe for oil cooling, but if it was a great idea why is no one still doing it?
The weight saving benefits would have been less than.err.... blowing your nose, or a quick one off the wrist prior to racing.:confused:

I added the TKM engine because it was in the same mag. They still do make Kart engines.

[TZ350]

253907

Measured the volumes of the transfer ducts.

Right hand tripple port cylinder with 1.3, 1.2 and 1.1 area ratios

Trans A = 24
Trans B = 16
Trans C = 8
Total = 48cc for all transfer ducts combined.

Left hand single port cylinder

Trans A = 40
Trans B = 20
Trans C = 8
Total = 68cc for all transfer ducts combined.

A lot of the fresh charge must be, being transfed from the crankcase.

[jasonu]

...they just need to be able to show up to/start races

Fixed it for ya.

[husaberg]

Fixed it for ya.

Kickaha bike has been out of action while Suzuki re manufacture enough valves for the GN to complete 3 race meetings.:laugh:

He is also waiting for the next season of American Chopper to get some ideas for a tank mural.

[jasonu]

Kickaha bike has been out of action while Suzuki re manufacture enough valves for the GN to complete 3 race meetings.:laugh:

He is also waiting for the next season of American Chopper to get some ideas for a tank mural.

Now that is some funny shit!

[Kickaha]

Kickaha bike has been out of action while Suzuki re manufacture enough valves for the GN to complete 3 race meetings.:laugh:

He is also waiting for the next season of American Chopper to get some ideas for a tank mural.

No they have got the valves in stock, they last 2-1/2 seasons of 11-12,000 rpm abuse before they let go except if you use aftermarket then they last 1- 1/2 meetings

I think the tank might stay

[husaberg]

No they have got the valves in stock, they last 2-1/2 seasons of 11-12,000 rpm abuse before they let go except if you use aftermarket then they last 1- 1/2 meetings

I think the tank might stay

Tell you what if i beat you at Grey on the GN Bucket vs 2 stroke Bucket Challenge.
Will you then let me take it off your bike and shoot it a couple of times.
Then mount it on My wall as a trophy head next to the stags Thar horse possum and other animals i have er... Ran over in my ute?

[NordieBoy]

I agree, I'm happy with my chances with the plans I have. Just need another ten years to get them sorted.

2 strokes and cheese. Both better with time.

[koba]

253902

The transfer specs call for a area ratio between transfer port window and tract entry of 1.3:1 (main transfer).

253901

The tripple port cylinder on the right has had the duct entry closed up to a ratio of 1.3, it looks very small to me but the inner radius has a better looking curve to it.

Looks like good results at some hard, fiddly work there. I've been thinking of having a play doing something similar.




The weight saving benefits would have been less than.err.... blowing your nose, or a quick one off the wrist prior to racing.:confused:



I have an emotional response to ultra-detail weight savings like cored bolts and holes everywhere possible.
However, In working out my new subframe I sat down and worked out what the weight savings would actually be from drilling heaps of holes through the neutral centre of the square tube. I can't remember the specifics but it was something like 77 grams saved by drilling that would take all day to do properly.
One could spend all that time doing far more productive things to actually make the bike go faster.

Might do it anyway; just 'coz shit like that gives me a long, hard fat.


Tell you what if i beat you at Grey on the GN Bucket vs 2 stroke Bucket Challenge.
Will you then let me take it off your bike and shoot it a couple of times.
Then mount it on My wall as a trophy head next to the stags Thar horse possum and other animals i have er... Ran over in my ute?

And what would the other side of the bet be?

You know, if you loose...

[Henk]

You know, if you loose...

oh come on now, be serious

[Kickaha]

oh come on now, be serious

yes, you mean "when"

[Grumph]

Tell you what if i beat you at Grey on the GN Bucket vs 2 stroke Bucket Challenge.
Will you then let me take it off your bike and shoot it a couple of times.
Then mount it on My wall as a trophy head next to the stags Thar horse possum and other animals i have er... Ran over in my ute?

Given that Wobbly seems to be involved hands - on in Husaberg's project, Wawick, you'd better bring the GN out here....

Bear in mind I have no computer tuning aids and my dyno is the road up to the local sawmill....sounds like just the challenge.

Can we specify rider ages are to be similar ? No young hired guns ?

[husaberg]

Given that Wobbly seems to be involved hands - on in Husaberg's project, Wawick, you'd better bring the GN out here....

Bear in mind I have no computer tuning aids and my dyno is the road up to the local sawmill....sounds like just the challenge.

Can we specify rider ages are to be similar ? No young hired guns ?

When you hired guns is it all right if the rider is er... Free

rider weight is middle aged as is the rider i will pilot the bitch myself. Chicks dig scars.


Bellow some 90's GP stuff

[Grumph]

When you hired guns is it all right if the rider is er... Free

Never had a young gun on your bike have you ? the buggers expect to be fed !!! The least they could do is starve for their sport...

[husaberg]

Never had a young gun on your bike have you ? the buggers expect to be fed !!! The least they could do is starve for their sport...

When i was first racing from 16-20 one of my fathers friends who always had a heap of spare bikes used to lend me his when mine broke.

I used to repay his generosity on most occasions, by er....crashing them repeatably. Lovely guy Bruce Wearing I miss him. Never told me off just shock his head and tut tuted a bit. He had a 175 Aermachi for a while i wonder where it went? also a Mach 2 250 and a C15. I own his old 350 Honda, I just don't know who has "borrowed it" at the moment.

[husaberg]

If I remember correctly (1926 is some time back) the Garelli 350 Competizione was a split single allright, but unlike the later DKW split-single racers it did not have forked or articulated conrods. The Garelli was a normal 360° (both pistons rising and falling simultaneously) parallel twin with three transfer ports in the left cylinder and two exhaust ports in the right cylinder. Both cylinders shared a common combustion chamber. Each piston commanded two carburetters. Also unlike the DKWs, the Garelli had no auxiliary pump cylinder or blower of any kind.
I do like the look of the Garelli's exhaust pipes. It is the oldest bike I know of with such modern-looking pipes. Using diffusers to promote suction was not yet common practice then, and adding end cones would be regarded as revolutionary 26 years later! But I suspect that neither the exhaust timing nor the blowdown time.area of the Garelli did the end cones much justice; they were probably shaped like this just to accomodate the fish-tails.

I would not bother with offsetting cylinders or piston pins to achieve asymmetrical timing. The effect is very small and who needs the complication.
The pic below shows a calculation I did on the Aprilia RSA125. I gave it an offset of no less than 10% of the stroke in order to enhance the effect.
It is obvious that the maximum conrod angles become asymmetric. What may be less obvious, is the increase in piston stroke for a given crankshaft stroke!
It is also remarkable that it takes more than 180 crank degrees from TDC to BDC, and less than 180° from BDC to TDC.

Thanks for your reply Frits and Grumph I actually thought the offsetting might decrease the stroke but i guess my cockeyed math was a little crap.

But to save me stealing my kids compass and protractor would moving the cylinder forward or backwards actually have the same effect as the offset of the pin?
No doubt fits or wob can click a few keys on the keyboard? if not i will try to draw it out to see old school style. the 12mm offset did seem to make a meaningful difference on the sim with no other changes to spec to suit. it may have been a lot less reliablw though no doubt. Slapwise


Below is the Swiss Auto/ ELF/ ROC /MZ /Pulse V4 500 GP bike Bill Bucley has a Pulse 500 don't know if that has a ROC frame but i guess ir does.

[Frits Overmars]

But to save me stealing my kids compass and protractor would moving the cylinder forward or backwards actually have the same effect as the offset of the pin?
No doubt fits or wob can click a few keys on the keyboard? if not i will try to draw it out to see old school style.If I tell you, you'll know. If you draw it, you'll understand :shifty:.

[NordieBoy]

If I tell you, you'll know. If you draw it, you'll understand :shifty:.

Frits Yodamars.

Anyone else read that with Yoda's voice in their head?

[TZ350]

253985

Got the piston off and had a look at the underside of the crown, well that looks about the right amount of stain so not excessivly hot then.

253986

Heated the piston and carfully removed the trapped ring. If I could I was going to re cycle it and the piston.

253987

Perfect .... good for another 100,000 km's

253984

Chris V went to a lot of trouble and carefully measured everything up for me. It turns out that there was an excessive amount of clearance and the consensus was, that the piston slapping back and forth had hammered the ring lands trapping the ring.

[Yow Ling]

Maybe posted before, bit of a goldmine, maybe just a coalmine

http://www.mitaka.co.uk/catalogue_index.htm

[Ivan]

what happened to thomas from the first post is he still building the bikes?

[teriks]

The Roberts Aluminium bike was at Wanganui and I managed to bleg Henks camera as we were having a nosey.

Here is a pic of the dimpling I was talking about.
Again I say, I'm not sure how useful it would be; just a thought.

253899

WOW, that's pure areodynamic perfection. You know why golf balls hav.. oh wait a minute ;)

I'm impressed by the amount of work gone into that, but the return in reduced mass or improved heat transfer must be very very small.

[TZ350]

254000

Had a FXR up on the dyno today, it had a bit of a hole in the 6-8,000 ish range.

254003

Std short inlet, good up top but resonance hole down low.

254002

I had posted before about how I thought a long inlets resonance could be changed by opening/closing holes in it like a musical instrument.

Long to get rid of the resonance hole, or improve bottom end and short (open hole) for top end.

254004

For the test I simply Blocked the hole with my thumb and opened it about 8K. I think an inlet could be quite long with a series of holes opened in sequence.

254001

Red line std carb, Blue line, long inlet with hole, hole closed, resonance dip disapeared, hole open, good top end.

Narr ... can't see any value in a variable tuned inlet system like this, its too simple.

[NordieBoy]

WOW, that's pure areodynamic perfection. You know why golf balls hav.. oh wait a minute ;)

I'm impressed by the amount of work gone into that, but the return in reduced mass or improved heat transfer must be very very small.

That would be around double the surface area though?

Ever seen Tiger Woods pause play because of overheated balls?

[bucketracer]

254001

Red line std carb, Blue line, long inlet with hole, hole closed, resonance dip disapeared, hole open, good top end. A simple variable tuned inlet system.

Stunning ... is this a first, never seen this way of tuning inlet resanance talked about in the go fast forums before.

[husaberg]

Stunning ... is this a first, never seen this way of tuning inlet resanance talked about in the go fast forums before.

Play it again TZ

That is a note worthy discovery

Its all about the Harmony. or is it Harmonics?

Interesting. Leonardo Da Vinci was a artist/inventor in the " resanance" as well.

Fittingly this is a link to the $2 Bell mouth.
Don't know if we still have Woolworth's department stores in NZ
http://autospeed.com/cms/A_110771/article.html

[NordieBoy]

Stunning ... is this a first, never seen this way of tuning inlet resanance talked about in the go fast forums before.

Only a problem when you need to use the clutch and cover the hole at the same time...

[kel]

Only a problem when you need to use the clutch and cover the hole at the same time...

Im concerned my hand might get trapped under the tank in tight left handers. Keeping in mind the curve is aimed at Kart track racing; we had it producing over 20hp but the fueling at 8k was appauling, damn thing wouldnt take anything like full throttle. The longer the inlet tract the less the problem, at 100mm length it would comfortably pull through with full throttle but fall on its face in the higher revs. After 56 pulls on the dyno TZ's not so secret inlet system was by far the best solution for spread of power. Seems ESE's talents arent just limited to 2 strokes, very impressed :drinknsin

[bucketracer]

Fittingly this is a link to the $2 Bell mouth.
Don't know if we still have Woolworth's department stores in NZ
http://autospeed.com/cms/A_110771/article.html

Bellmouth made froam an egg cup, good one.

[Grumph]

A rotary collar over the hole linked to an exup actuator motor....voila ! ....I give you the InUP Valve.

Actually, it's a bloody heimholtz resonator and you're tuning it by varying the inlet orifice size.

[dmcca]

Ok .... this is where the simulated rubber hits the road.

We are going to see if we can make this.

253550

Red line is my efforts with EngMod2T, Blue line is after Wobbly polished it up a bit and replaced the RS pipe with one of his own design.



TZ, Im loving your build pics and posts... thanks...

Are you able to share any of the changes wobbly made to improve the power spread aside from the pipe... no need for specific numbers, just general concepts... particularly interested in the big ?improvement in low end. Are there any big ticket changes that led to the improvement over your initial design or just lots of small refinements adding up?

Cant wait to see the dyno results!!

[TZ350]

Wobbly has polished my original file, its his experiance that has made the difference, the adjustments to the each individual entry are small but they add up to a lot.

[TZ350]

... it's a heimholtz resonator and you're tuning it by varying the inlet orifice size.

That makes sense ...

It seems very effective, has it been done this way before? anyone seen any references.

[Moooools]

A rotary collar over the hole linked to an exup actuator motor....voila ! ....I give you the InUP Valve.

Actually, it's a bloody heimholtz resonator and you're tuning it by varying the inlet orifice size.

I would agree here.

The system you are using does not act in the same way as a musical instrument. Not at all. A musical interment uses standing waves, which have no velocity (or very very little. Now you tell me how waves with no velocity get into the engine.

In reality most of the air in the tube acts as a spring, and air at the opening acts as a mass. The mass of air oscillates on the end of the spring when the valve closes, and then when the valve opens the air is already traveling towards the inlet and it is easier to suck in.

By opening the hole all you are doing (in theory) is changing the volume of the 'air spring' that exists between the hole intake and the inlet valve.
While is appears to work I think that those are empirical results (they work just because). If it was working like you said and you covered half of the hole it would produce very nearly the same result. However if I am right it would have a significant effect on performance.

For repeatable results changing the length or diameter of the inlet is the only way to do it.

Oh but nice work getting some extra power out of the FXR. I am just a physics dickhead.

[bucketracer]

For repeatable results changing the length or diameter of the inlet is the only way to do it.

They may have done more than one run.

I suspect they did enough runs to satisfy themselves that it was a repeatable event and it only needs to be automated to be useful.

[Grumph]

That makes sense ...

It seems very effective, has it been done this way before? anyone seen any references.

The nearest thing to what you did is not the published heimholtz resonator stuff but I think the papers published by Annan? and Roe regarding side cavity resonances in SILENCERS....Internationally the silencing regs favour attenuating noise over certain frequencies and these papers related to tuning mufflers to the required frequencies using side cavities and different size orifices.

It would appear to me that the FXR had unfavourable wave activity at one rpm frequency - using the side orifice you made the inlet tract resonate at a different frequency which happened to make more power....The sheer size of the "bellmouth" has turned it into a resonant cavity which happens to be open to the air at one end.

[Moooools]

They may have done more than one run.

I suspect they did enough runs to satisfy themselves that it was a repeatable event and it only needs to be automated to be useful.

I mean repeatable in terms of you could two variables against each other and you would end up with nice curve.

I don't think that this method would produce a curve if you graphed length between hole and carb against increase in power at a given RPM.

[TZ350]

The system you are using does not act in the same way as a musical instrument. Not at all. A musical interment uses standing waves, which have no velocity (or very very little. Now you tell me how waves with no velocity get into the engine.


Yes I remember you explanation from before, and there sure was plenty of dynamic action with air blowing and sucking very strongly through the hole, so no standing waves there, like you say the action is something else.

Maybe I should have made it clearer that my comparison to the musical instruments this time was the action of uncovering the holes like a woodwind that changed the inlet tracts effect on the torque curve.


In reality most of the air in the tube acts as a spring, and air at the opening acts as a mass. The mass of air oscillates on the end of the spring


I think what’s happening is that the open hole destroys most of the spring effect reducing the springy bit of the inlet tract to the bit from the valve head to the first open hole and the bit from the open hole to the bell mouth becomes more flow than spring.

If this is true then there could be a series of holes at different distances from the valve which are progressively uncovered and in that way the torque curve could be held long and flat over an extended range.

Whatever the physics, it worked well on the dyno, we did in excess of 50 runs trying different inlet lengths etc and maybe 10 or so runs confirming the inlet tract hole results.

Thanks for your input.

[TZ350]

I don't think that this method would produce a curve if you graphed length between hole and carb against increase in power at a given RPM.

No, you wouldn't want to graph power thats the wrong result to look at, This is about cylinder filling and BMEP or torque.

Its the inlets effect on the torque curve thats important.

[Moooools]

Yes I remember you explanation from before, and there sure was plenty of dynamic action with air blowing and sucking very strongly through the hole, so no standing waves there, like you say the action is something else.

Maybe I should have made it clearer that my comparison to the musical instruments was the action of uncovering the holes like a woodwind that changed the inlet tracts effect on the torque curve.



I think what’s happening is that the open hole destroys most of the spring effect reducing the springy bit of the inlet tract to the bit from the valve head to the first open hole.

If this is true then there could be a series of holes at different distances from the valve which are progressively opened and in that way the torque curve could be held long and flat over an extended range.



Not sure by what you mean by "For Repeatable Results" do you mean this might not work tomorrow if we tried it again or that it may not be transportable to a different engine?

Thankyou for your input.

Repeatable as above.

Yes I would agree that that it is probably killing the resonance effect so it still works.

This discussion has me thinking about doing a tuned inlet myself, instead of just sitting here telling you that you are wrong.
Maybe when I clean up my bike next month I will have a crack at it. Then I just need to fork out some dosh for Dyno time.

[Moooools]

No, you wouldn't want to graph power thats the wrong result to look at, This is about cylinder filling and BMEP or torque.

Its the inlets effect on the torque curve thats important.

What he said.

Except that at a given rpm power is just a multiple of torque.

[TZ350]

Yes I would agree that that it is probably killing the resonance effect so it still works.

Yes certainly, the dyno tells use something usefull is happining.

I wanted to try a very long inlet with several holes but we ran out of time. I guess the ideal would be to try several different length bellmouths then a long one with holes the same length as the bellmouths and compair the results.

I am looking forward to hearing about your own experiments.

[TZ350]

Except that at a given rpm power is just a multiple of torque.

True, maybe your right, as there are three variables, rpm, inlet length to the first hole and torque.

254019 254020 254023

What really surprised me was the inlet with the hole closed was crap up top but with the hole open it had the tuned length (to the hole) of the carb but made better power up top than the carb did. I would have thought the plumbing of the long inlet would have been more restrictive to air flow than the naked carb and made less power.

[Moooools]

True,

254019 254020

Maybe your right, there is three variables, rpm, inlet length to the first hole and torque. Idealy you want to maintain a flat (but high) torque curve throughout the rpm range.

Well with on three axis of course.

I can't quite think but maybe something like this.

http://www.livephysics.com/ptools/online-3d-function-grapher.php?ymin=-1&xmin=-5&zmin=Auto&ymax=1&xmax=5&zmax=Auto&f=%28%281%2Fsqrt%283.14*0.5%5E2%29%29%29*e%5E%28-%28x%5E2%2F4%29%29-2*y

[Yow Ling]

Well with on three axis of course.

I can't quite think but maybe something like this.

http://www.livephysics.com/ptools/online-3d-function-grapher.php?ymin=-1&xmin=-5&zmin=Auto&ymax=1&xmax=5&zmax=Auto&f=%28%281%2Fsqrt%283.14*0.5%5E2%29%29%29*e%5E%28-%28x%5E2%2F4%29%29-2*y

Ahh the Brainy asian girls site, must do more homework

254028

[Yow Ling]

Really interesting stuff with the flute inlet, is this just a simple way of varaible trumpet length like on the Norton/Roton rotaries.

I have modified a RZ350 PV controller so it opens at different rpms etc and opens different angles, yamaha used the same controller for everything rz250/350, tdr250, Vmax, exup, you just change the jumpers or put some dipswitches where the jumpers were, cheaper than getting the all singing Ignitech for something like this . just needs a ignition signal.

Does the engine note change when you cover the hole?

[TZ350]

... is this just a simple way of varaible trumpet length like on the Norton/Roton rotaries ... Does the engine note change when you cover the hole?

I am expecting that with several holes you could get a step wise result that mimics the Norton rotaries, next time that FZR is on the dyno I will try to do some more tests.

The engine note in the 6-8K rpm range changed from running roughly to running well.

I would like to know more about the RZ servo controlers.

[kel]

Im certainly no expert on these things but I think in part the longer inlet was cancelling the negative effect of the Mega phone exhaust at 8k, opening the inlet hole at 8.5k seemed to shorten the inlet tuned length and allow the mega phone to do its work within its range. When I removed the mega phone from the Lesoft engine model it immediately picked up 2 hp at 8k just as we saw with TZ's inlet, but then it also lost the hump in the 9 to 11k range.
Hopefully Frits might explain what we were seeing (I know 4 strokes arent your thing Frits, perhaps you could consider it purely for the physics)

[Yow Ling]

http://tzr250.com/forums/index.php/topic,753.30.html:the

[TerraRoot]

the MV F4 has a variable intake, but instead of a hole (which mustn't flow very well) an extra length of trumpet is lowered on to the set trumpet, works quite well i think.
http://www.sportrider.com/news/146_0911_2010_mv_agusta_f4_1000_r_unveiled_at_mila n_eicma/photo_02.html

[TZ350]

254034

I was expecting the hole to flow worse to (blue line), ie less power but it made more power on the dyno than the std carb (red line) it was being compaired too.


the MV F4 has a variable intake, but instead of a hole (which mustn't flow very well) an extra length of trumpet is lowered on to the set trumpet, works quite well i think.

254033

http://www.sportrider.com/news/146_0911_2010_mv_agusta_f4_1000_r_unveiled_at_mila n_eicma/photo_02.html

1980's Nortan Rotary racer with variable inlet.

<iframe src="http://www.youtube.com/embed/48foOHK2tyA" allowfullscreen="" width="560" frameborder="0" height="315"></iframe>

Norton Rotary at the TT

<iframe src="http://www.youtube.com/embed/VcF9vwOCXBQ" allowfullscreen="" width="420" frameborder="0" height="315"></iframe>

A quick trot around the Island.

<iframe src="http://www.youtube.com/embed/I3iWgDdGlRw" allowfullscreen="" width="420" frameborder="0" height="315"></iframe>

And this is how fast they were in their day ....

<iframe src="http://www.youtube.com/embed/kBg86bjr8l0" allowfullscreen="" width="420" frameborder="0" height="315"></iframe>

[NordieBoy]

What really surprised me was the inlet with the hole closed was crap up top but with the hole open it had the tuned length (to the hole) of the carb but made better power up top than the carb did. I would have thought the plumbing of the long inlet would have been more restrictive to air flow than the naked carb and made less power.

Maybe what you want is an inlet with a longer slot the width of the hole and a moveable sleeve with the hole. Then you can move the hole toward either end of the intake?

[TerraRoot]

i think the hole does flow worse then if the bell mouth was the correct length.
longer intakes move the torque down lower in the rev range but if its sooo long (like it is) the cams profile is probably working against it and bingo big hole in the rev range.

[teriks]

That would be around double the surface area though?

Ever seen Tiger Woods pause play because of overheated balls?
Well, maybe not golf balls...



:psst: Daily News 2010: (http://articles.nydailynews.com/2010-01-19/gossip/17943385_1_tiger-woods-rehab-benoit-denizet-lewis) "Tiger Woods is being treated for sex addiction at a posh clinic" "He's not going to be allowed to go out and golf in the morning,"


Re. the dimpling, I'm simply questioning the return on invested time.

[wobbly]

Just a small reply re the Pulse bike that Bill has in his lounge - the chassis geometry was designed by Mike Sinclair and built by
the Roberts factory in Milton Keynes.
I have a bare one here in my workshop, that I am looking to stick a 400F3 engine into ( nothing better to do - you know how it is ).

I love the side resonant ( thats what Prof Blair calls that setup in his books ) "flute" idea - I understand that several new super-bikes have variable trumpet length that is actuated by rotating the outer trumpet sleeve.
This is fixed to the inner on a peg, with a spiral slot on the inside of the outer.As it rotates, it lengthens the trumpet on this long pitched screw slot.
You could use the same idea by uncovering staggered holes as the outer rotates, without changing the length.

[TZ350]

254056


... I love the side resonant ( thats what Prof Blair calls that setup in his books ) "flute" idea -

Great minds think alike ... :msn-wink: .... right.

[Ocean1]

You could use the same idea by uncovering staggered holes as the outer rotates, without changing the length.

Or a slot, (stepless).

[wobbly]

Then go another step, and I bet you a free blowy that a progressively varying slot width is what is needed to get the the optimum effect at differing rpm.

[Ocean1]

Then go another step, and I bet you a free blowy that a progressively varying slot width is what is needed to get the the optimum effect at differing rpm.

A step further: make the moving element a sleave with a radial slot, the intake tract with an axial slot of varying width. It means you can vary the cross sectional area of the bleed aperature to exactly suit the revs (+ and -) while allowing the sleave movement to be linear.

[Yow Ling]

A step further: make the moving element a sleave with a radial slot, the intake tract with an axial slot of varying width. It means you can vary the cross sectional area of the bleed aperature to exactly suit the revs (+ and -) while allowing the sleave movement to be linear.

So long as it has USB and a Facebook interface it will be great

[jasonu]

Then go another step, and I bet you a free blowy that a progressively varying slot width is what is needed to get the the optimum effect at differing rpm.

I'd want to know who the free blowy is coming from BEFORE accepting that wager...

[TZ350]

254057 254058

:scratch:now could there be any benefit in adding a variable tuned length to the bellmouth of my pumper carb? Narrr probably not! ... why would someone want a massive ramming effect from the inlet tract through out the power range?

[Grumph]

254057 254058

:scratch:now could there be any benefit in adding a variable tuned length to the bellmouth of my pumper carb? Narrr probably not! ... why would someone want a massive ramming effect from the inlet tract through out the power range?

Am I the lone voice here who says you're not lengthening the inlet tract with that huge carb extension ? Factories deliberately make the OD of the bellmouth area - where a hose to an aircleaner would attatch, and where your extension attatches - large enough to avoid any entry flow effects when there is a hose or similar on there. If your bellmouth was the same ID as the carb bore then yes you're lengthening the tract....you're not !

What you are doing as has already been said is adding a short resonant chamber onto the entry of the carb. Yes, a heimholtz resonator.

IMO you got lucky when you saw a cleaning up of the carburation over a limited range...it could just as easily have gone the other way.

Normally when tuning 4 strokes you'd change needles to achieve the same result while leaving the inlet tract length correct for max power rpm.

[bucketracer]

Am I the lone voice here who says you're not lengthening the inlet tract with that huge carb extension ? - If your bellmouth was the same ID as the carb bore then yes you're lengthening the tract....you're not !


254067

What is the function of a velocity stack on an Amal carb, they are bigger at the carb end than the carb throat.


Normally when tuning 4 strokes you'd change needles to achieve the same result while leaving the inlet tract length correct for max power rpm.

They will have tried that. Anyway why leave it "correct for max power" when you can vary it for better performance throughout the range?


IMO you got lucky when you saw a cleaning up of the carburation over a limited range...it could just as easily have gone the other way.

Didn't so its a useful technique ...


What you are doing as has already been said is adding a short resonant chamber onto the entry of the carb. Yes, a heimholtz resonator.

Yes a series resonant chamber, TeeZee has been talking about that. He thinks more experimenting is called for ...

A series resonant chamber in sync with and feeding the inlet tract proper can't be a bad thing can it?

[Grumph]

254067

What is the function of a velocity stack on an Amal carb, they are bigger at the carb end than the carb throat.

The function is to clean up airflow at the entry - no more than that as there is a step remaining at the entry. The real ones are the same bore as the carb. Most are cosmetic.



They will have tried that.

Not stated...and needles are often not available for OE carbs...



Didn't so its a useful technique ...

In some - very closely defined, circumstances



Yes a series resonant chamber, TeeZee has been talking about that. He thinks more experimenting is called for ...

So do all the serious researchers

[bucketracer]

""The function is to clean up airflow at the entry - no more than that as there is a step remaining at the entry.""

The cleaning up of the air flow is what TeeZee thinks is the reason that the longer inlet with the hole made better power than the open carb and is also why he can flow quite a bit of air through a 24mm venture when its fitted behind the slide of a bigger carb. He thinks the bell mouth and first part of the carb gets the air flowing in the right direction.

[bucketracer]

So do all the serious researchers

Grumph maybe they could post something enlightening themselves ... by any chance, do you see yourself as a researcher too?

[Moooools]

Well here is how I would do it. Even though I may be pissing into the wind a bit.

My theory: isolate most of the spring action from the straight shot of incoming air.
THoughts

(sorry for continuing on with this 4 stroke nonsense)

[Kickaha]

(sorry for continuing on with this 4 stroke nonsense)

There is a four stroke tuning thread but none has posted since 2009 http://www.kiwibiker.co.nz/forums/showthread.php/102190-Four-stroke-performance-tuning

I think they're all to busy out riding their bikes and winning races than typing out hundreds of page of crap on how to make your bikes go fast :whistle:

[TZ350]

I think they're all to busy out riding their bikes and winning races than typing out hundreds of page of crap on how to make your bikes go fast :whistle:

Its not every day I agree with Kickaha :motu: about 4-Strokes and there value to mankind, but what he said could be true ..... :laugh:

[husaberg]

Its not every day I agree with Kickaha :motu: about 4-Strokes, but what he said could be true ..... :laugh:

Shame he is a little less forthcoming with his official acceptance of the 2 vs 4 "old fat buggers challenge at Greymouth Street races 2012."*
Maybe suzuki don't have a large enough stock of valves after all.:bleh:
I hear from reliable sources Suzuki actually decreased production of valves after kickaha stopped racing the GN.:lol:
Shit kicka, you will only need ...lets see is it 4 races plus one practice, So @ 2 valves per race time four races.plus 2 for practice.... That's only 10 valves, baring any unexpected blowups i guess.

What will side of the bet will be.er.... I will put a GN125 tank on my bike.
If anyone asks why (No doubt they will for f sakes) I would put such an ugly chopper tank on a race bike.
I will tell them without laughing (too much) that its because "GN125s peanut tanks are f...ing Awesome."


*Old fat buggers challenge only applies to Warwick and the old Gn125

[Grumph]

Grumph maybe they they could post something enlightening themselves ... by any chance, do you see yourself as a researcher too?

Shit no...I'm just an old bastard who's been building winning motors for over 40 years...I've met the researchers and listened carefully too
Some were worth listening to, some off in their own dream worlds.Blair was good - on 4 strokes.....
I've read a lot of papers and tend to remember the relevant bits but finding them on the net and posting them....sorry, too much work on here.

Some 4 stroke work has relevance to this 2 stroke thread but fercrissake know your history of 4 stroke inlet development before trying to adopt inappropriate techniques to 2 strokes.

The telescopic inlet trumpets on injected motors you will note are pretty constant ID - which is the ID of the inlet port at the head.

[TZ350]

The big picture is, it did clean up a resonant hole created by a bit of megaphonitis a common problem so its a technique that might be useful on another day and the idea may have possibilities in other ways too.


Am I the lone voice here who says you're not lengthening the inlet tract with that huge carb extension ? Factories deliberately make the OD of the bellmouth area - where a hose to an aircleaner would attatch, and where your extension attatches - large enough to avoid any entry flow effects when there is a hose or similar on there. If your bellmouth was the same ID as the carb bore then yes you're lengthening the tract....you're not !

What you are doing as has already been said is adding a short resonant chamber onto the entry of the carb. Yes, a heimholtz resonator.

I think you are the lone voice that’s connecting the inlet tract proper to the carb extension, I am not sure that I did that, in fact I deliberately avoided doing so.

I had an idea, did some tests and got a good result. In getting my head around what was happening, the components of the inlet system and the relationship between them (hadn't realy had to think about the bit in front of the carb before) I was being a little cautious as I suspected there was a bit more to the story and only used the term "inlet" and that was because it’s not the exhaust.

The carb extension is part of the inlet and later with some thought I could see how it was possibly acting as a secondary resonant system. But thanks for you’re input and comment from others because that has clarified it for me and no doubt other readers too.

Now, I would like to see if this could be tuned to work with the inlet tract and force, ram or deliver (whatever word you want to use) more mixture.

Another thing I would like to try is extending the “inlet tract” and try the moving hole idea, there are a few learned people who think it may have possibilities so its worth a try. I will use EngMod2T to simulate it first of course, quicker and cheaper.

I am a bit of a newbe and only making a lowly 230 hp per litre, (Speedpro is making 300) considering the motors origins, thats respectable. The only difference between them and bigger engines is probably the cost and the fact we mostly do it all for ourselves learning as we go.

Shoot down merchants and holier than thous are two a penny on the net but a person who will impart real knowledge in an open way is absolute gold and this is the thread for them.

Grumph you sound like you know what you’re on about, I would love to see some posts about your own projects and ideas or techniques that you think are valuable.

[TerraRoot]

Shoot down merchants and holier than thous are two a penny on the net but a person who will impart real knowledge in an open way is absolute gold and this is the thread for them.



a-fucking-men :cool:

[husaberg]

Queens University Belfast or QUB

Most of us have heard of it.
Home of Prof Fleck and the Late Prof Blair.
The Irish sure do love there road racing.
Just when i thought i had it cracked on posting the attachments it goes and puts them all in reverse order.
It also looks like Tony Foale was beaten to the spine frame (he seems to claim to have had the idea stolen from Waddon) as well, by one Colin Seeley interestingly he was the team boss for the Norton Rotary for a while at least.As above.
He also manufactured the most beautiful Seeley G50 and made quite a few frames including the frame for the original Ducati V twin racers they continued to use his elegant chain adjusters for a number of years.

[Kickaha]

It also looks like Tony Foale was beaten to the spine frame (he seems to claim to have had the idea stolen from Waddon) as well, by one Colin Seeley interestingly he was the team boss for the Norton Rotary for a while at least.As above.
He also manufactured the most beautiful Seeley G50 and made quite a few frames including the frame for the original Ducati V twin racers they continued to use his elegant chain adjusters for a number of years.

Colin Seeley will be over here fo the Puke Classic festival this year, get him to knock one up for the bucket while he's visiting

[husaberg]

As you remember the original Yamaha engines supplied to the privateers were non big bank ROC had one for a number of years at least 3 years after the works boys all had them Harris finally got one.

I did some research into why Doohan went back to the screamer engine it appears that when they first came out they were indeed faster if not less powerful than the Screamer.
To get an acceptable level of vibration with the big bang Honda added a much heavier balance shaft to their single crank V4.
The bike sounded slower and even felt slower to Doohan, but the lap times were faster as it was much kinder on the tires and more user friendly.

Latter when it was felt that some more power would be an advantage and more importantly the tire technology had evolved and caught up with the power outputs. Not to mention the power delivery that was soften by the low lead fuels then required They again tried the screamer motor Doohan liked it. But the other factory rider Caparossi was thrown off after a couple of laps.
As most of his teammates and Competitors by that stage hadn't rode a screamer, it was a major physiological advantage for Doohan as well.

The interesting thing is that they kept the heavier Balance shafts. As it turned better with it in. Something to do with the counter rotating balance shaft cancelling out to some extent the Gyroscopic forces of the crank. I think it was less wheelie prone too.
He also probably by this stage getting a bit bored as well.

Re kickaha above

Colin Seeley will be over here fo the Puke Classic festival this year, get him to knock one up for the bucket while he's visiting
Take a pic of your bike with you and ask him what he thinks of your peanut tank:spanking:

Forgot to mention as Kickaha is aware he was the British sidecar Champion as well. So no doubt he will have kichaha cleaning his shoes and thus forth.:not:

The last attachment is a good case of how we should always measure at least twice (more for me) and cut once.

[TZ350]

A bit of trivia.

There was another company before Buckleys in the nuclear science business here in NZ called ANAC, they were over the road from St Lukes in Auckland. Unfortunately they folded during the 30% interest on overdrafts era of Muldoons clever fiscal management.

Bill B used to do the engineering for them. Any way there was a character working at ANAC called George. George is very clever and was their problem solver. There was no tec problem that George couldn’t find a solution to, he was a very valuable man and worked as a subcontractor to them.

George’s interest was alternative energy and automotive power from wood gas. He drove a small truck with a gasifier on it, something he made himself. He came from out west and the truck proved very reliable but not quick to start, after work he would have to fire the burner up before getting washed and changed, by the time he clocked out it was ready to go.

Now working in overalls and driving a gasified ute made from an old car was something that some of the social climbing status conscious elements in management from academia struggled to relate to and they were sometimes a bit offhand with George.

Now the thing that used to make me laugh was that occasionally management would piss George right off. And when he felt particularly offended he would not collect his pay for 3 or 4 months, letting it mount up.

Now the management enjoyed a table in the smoko room in a prime location right in front of a large window. After 3-4 months of letting his pay accumulate George would arrive in his Rolls Royce at morning tea time, roll right up to the window and toot his horn. At which point management knew they had to scramble to find his back pay, which usually had amounted to a tidy sum by then.

Geroge thought it paid to remind the suckup elements in management what he was worth occasionally.

Anyway, made me laugh, sitting at smoko and seeing the look on their faces, the Roller at the window and George tooting the horn …. the shop floor had a bit of a giggle.

[TZ350]

Because I was ask too...

254139 254140

Original 16hp run from a year or so ago (red line) and the resonant inlet extension (blue line). Hole uncovered at 8.5K.

[TZ350]

Making progress

254142

Measuring the squish clearance with a depth mike.

254143

The tape is to allow for the taper on the piston and give the chuck jaws something to grip. Skimming 0.25mm from the piston crown to set the squish and comp ratio (dished piston). The saddle is a bit sloopy and I had a woopsy when the tool was draged in and shit the piston.

254141

Ohoo well, allways wanted to use flat tops so in with a piston from a 93 YZ125.

254144

Skimmed a bit out of the head and got the clearance volume to 9.0cc spot on.

[jasonu]

Making progress

254142

Measuring the squish clearance with a depth mike.

254143

The tape is to allow for the taper on the piston and give the chuck jaws something to grip. Skimming 0.25mm from the piston crown to set the squish and comp ratio (dished piston). The saddle is a bit sloopy and I had a woopsy when the tool was draged in and shit the piston.

254141

Ohoo well, allways wanted to use flat tops so in with a piston from a 93 YZ125.

254144

Skimmed a bit out of the head and got the clearance volume to 9.0cc spot on.

Why did you machine both the piston and head when you could have got the required results by machining the head only? If you machine this piston you will be forced into machining every subsequent piston.
If the piston is being machined for profile reasons please disregard the above question.

[husaberg]

Most of us here in the South Island would have seen and heard this unique New Zealand Home brewed special
(Both the frequency and the amplitude are pretty unforgettable)

But i guess it might be interesting to the northerners.

George Begg's factory/Workshop must have been an exciting place to be after hours what with the construction of the F5000 cars and Burt Munro dropping in to borrow the use of equipment and materials and with specials such as this.

For those who didn't get to meet George he was a larger than life character himself (literally and figuratively)who didn't mind a bit of good natured ribbing
Even when he moved to Australia he rarely missed an Cams meeting.

Sadly missed.

[TZ350]

Why did you machine both the piston and head when you could have got the required results by machining the head only? If you machine this piston you will be forced into machining every subsequent piston.
If the piston is being machined for profile reasons please disregard the above question.

Was machining the 1990 KX125 dished (3cc) piston to get the squish (width) I wanted and at the same time reduce the combustion volume as it had become hard to realistically take much more off the head. Anyway I ruined the piston so went to a flat top that meant I now had to open up the combustion chamber in the head. I will stick with 1993 YZ125 flat tops now.

Why did I use those pistons, I had them in my junk box of goodies, and replacements are fairly available of Ebay.

[TZ350]

EngMod2T

254209

After getting that interesting result from the inlet with a hole that changed the resonant behaviour of the FXR's inlet system and overcame a megaphoneits problem I thought I should look at a ram tube for my 2-stroke engine.

254206

Ram Tube on the carb.

254207

I was hoping for more down low drive. Varing results with different lengths from 750 to 875 long, most make a little more top end but worse down low, the down low I think I can cure with the "hole" idea. But at an overall length of 1m for the inlet system its a bit unwieldy for little gain.

254205

I still need some sort of wind protection or still air box on my sticking out the side carb and in the past I had tried an air filter arrangement from a VW but it cost me a hp or so at the top end. But any way I thought I would simulate it as a short ram tube. At 300mm it showed the same results as the VW housing did on the dyno but as I shortened it it improved.

254204

A ram tube at 150x75mm shows a worthwhile topend power gain with no loss of torque down low. It will be interesting to see if this can be realised on the dyno.

[husaberg]

I still need some sort of wind protection or still air box on my sticking out the side carb and in the past I had tried an air filter arrangement from a VW but it cost me a hp or so at the top end. But any way I thought I would simulate it as a short ram tube. At 300mm it showed the same results as the VW housing did on the dyno but as I shortened it it improved.

Had you considered using something like this Below.
The carb seems tucked out of the way it has one of those water pumps Frits seem to like. It also has one of those Power valve thingies that seem to spread the power out a wee bit. It has a 6 speed gearbox was built in the last 20 years and most importantly is a Honda. I hear there is one at Tauranga.
It needs a bit of work mind you the Crank pokes to far up and to far down as well, The piston seems a little er...big as well. Oh well it can be fixed i guess.
As the RS frames seem to be a bit thin on the ground i am hoping it will fit in one of these. it should just about cram in there with a little persuasion

[bucketracer]

TeeZee had one look ... :eek: ... and went off for a lie-down .... :facepalm: I think he is .... :sick:

[TZ350]

EngMod2T

For something different Page 400 is going to be the basic info for building a 30+hp Suzuki GP125 taken from the EngMod2T simulation files.

254400 Crank HP. Simulated Dyno Graph from EngMod2T using an early RS125 pipe.

254399 EngMod2T's main screen for developing the model.

254401 Basic engine dimensions.

254402 Exhaust port dimensions.

254403 Transfer port and duct dimensions.

254404 Transfer port cylinder entry design and angles.

[TZ350]

EngMod2T

254407 Inlet port and disk timing info.

254408 Early RS125 chamber layout.

254409 24mm pumper carb and inlet tract model.

254410 Combustion data for a flat top piston.

254411 Air cool temp data.

254406 STA's or Specific Time Areas.

[husaberg]

I am only a little jealous .... so there. :crazy:

Don't be jealous your one actually has all the other bits that make it er..go under its own motive power. More importantly stop as well.
Ps don't panic about the 250cc bit on the side its only because it has an NSR250 cylinder and head on it. It seems they just bolt straight on

[TZ350]

This lot should have been on Page 360 but I was a bit slow getting around to it ….



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.



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



With regards to adjustable length pipes For (Expansion chambers). I seem to have picked up that they at least mostly lengthening for low end power.

Has anyone tried ones that just shorten for top end or a least over rev potential to me that would be a more logical solution?( I am not always logical mind you)
I know Cagiva ran a hydraulic system and someone posted a solution you like on pit-lane but I can't access the pic I have a log in and it would let me in?

You have to stay within certain length percentage limits for all elements of the exhaust system; you cannot make one part a lot longer or shorter in relation to the others without losing power somewhere.
It is best to concentrate on getting all dimensions correct for maximum power. In the high gears you don't ride low revs and in the low gears you'll have enough low-down power left to pull a wheelie or spin out the rear wheel (I'm not talking about buckets though, so you might want to reconsider your case).

If you have a decent setup for angle*areas, pipe, carburation and ignition, the necessary overrev potential will come naturally; no need to sacrifice maximum power in order to make it rev a little higher.


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

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


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

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

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

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




so would their be a (correct) ratio between c/case volume and transfer duct volume for a high performance engine?

Not really. The RSA's TDC crankcase volume is 675 cc (for a 125 cc engine!) but most of this volume is in the transfer ducts.


also on the rsa cylinder the liner has an opening in front of the boost port, while the honda 250 production racer has not,in the honda this is directly in front of the inlet from the reed block and appears to be an obstruction to the flow.


Over the years Honda has produced cylinders with and without the lip that your picture shows, sometimes both types in the same production year. But flow through the C-port is not the most important item of a fast cylinder.
Another point to help you make up your mind: compared to a Honda RS125 or RS250 the Aprilia RSA125 produces about 20% more power per cylinder....


... the important thing is that lower exhaust timings need bigger header diameters...some simple calculations, I have included one variable, the speed of sound. Starting with 550 m/s will get you in the right ballpark, after which you can vary this value according to your findings. Final remark: the calculation of the tailpipe restrictor diameter is critical: you can only apply it to engines that are thermally sound. Air-cooled engines are not...

Page 370 ….


The ring peg is right opposite the exhaust: the only decent place for it. Each time the ring passes over the exhaust port, it bulges out a little and then gets shoved back in its groove when it runs over the top and bottom port edges. If the ring peg is not diametrically opposite the exhaust port, this shoving back will cause the ring to rotate in its groove and every time it will hit the peg from the same side until the peg works loose....

Don't worry about the ring gap running over the C-port. The Aprilia's C-port is now 15 mm wide, but it has been as wide as 22 mm and even then there were never any ring problems.
Generally speaking you can say that the ring gap is safe over a C-port width of up to 40% of the bore. For steel rings that is; I never tried it with cast iron.......


The notch in the crankweb triggers the ignition. There's a Hall sensor at the crankcase looking at the crankshaft circumference. That gives a more accurate timing signal than a sensor looking at the end of a swaying shaft.

Below are some pictures of the Aprilia RSA125; the red arrows indicate the ignition sensor.


That notch for timing reminds me of one of the cleverest triggering setups I have seen.
In the SwissAuto/Pulse flying web engine there were two magnets at 180* in one crank web with only 1 sensor, setup much as the pic of the RSA125.
I spent ages trying to figure out how it worked, untill one day I grabbed another magnet and discovered that each one inside the crank
was orientated N & S pole outward.
The trigger sensed the N pole as cylinders 1,3 and the S pole as 2,4, bloody clever and as simple as it could be made.


The Haltech engine management syatem I have is exactly the same. S pole sets the system to "home" and fires channel 1, the N pole triggers channel 2.


The 3rd harmonic gives the best spread of power for a 2T, as it has a higher frequency but lower amplitude than the lower harmonics.
From messing about I have found that a length from the bellmouth correction to the 2/3 reed end length of around 135mm is good for a 125 running up past 12000
And another example being the RZ400 F3 engine the total length is 205 for tune at 10,000.


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



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.


Frits has given a good explanation of the reasons for fuel stand off in a rotary valver. Its also a clue to more power too, because if the stand off is at max power rpm, then it points to the possibility of closing the inlet a little later.

[husaberg]

It looks a real good unit, what is it? where did you get it from?

To tell you the truth I am not 100% sure if it is a NSR125 or a NSR150.
2t institute acquired it on Yahoo Japan.
It was dropped off in Australia and ended up in Tauranga.
It's there for some corrective surgery to fix the machining errors Honda made when they assumed it was going to be a road bike.:weird:

Stuff below is inspirational only. But you will get the idea of thinking behind the choice of engine.

[Yow Ling]

Welcome to the old men with big dreams club.
Looks pretty flash, so many good things coming out of the closet, Im not saying hondas are gay, just saying

Will look great with the peanut tank and tassels after Kick trashes you with the GN

[kel]

Had you considered using something like this Below.
It needs a bit of work mind you the Crank pokes to far up and to far down as well, The piston seems a little er...big as well. Oh well it can be fixed i guess.


Did you win the new years lotto draw?

[husaberg]

Did you win the new years lotto draw?
Cheaper than a good second hand FXR150 Motor. Never seen one:eek:

Right now this below is a Four stroke tuner Yes a Four stoke tuner. Worse still a Harley tuner and a side valve one at that. Who using a methodic appraoch was able to beat the factory bikes with only a part time effort. Please read between the lines as it were, because it is his approach is what i was tring to highlight. (Note the highighting has moved it bit Whoops) Also note what he was able to achieve with one go at a 500cc OHV Goldstar. Imagine if he had a go at two strokes.

[Henk]

Cheaper than a good second hand FXR150 Motor. Never seen one:eek:

I have, complete with all electrics $600, about what it costs to rebuild one when the rod piston and a couple of valves are shot.

[husaberg]

Welcome to the old men with big dreams club.
Looks pretty flash, so many good things coming out of the closet, Im not saying hondas are gay, just saying

Will look great with the peanut tank and tassels after Kick trashes you with the GN

I never agreed to tassles. Maybe an airbrushed mural if it was tasteful or some flames on the sidecovers.
Plus I hear Kick would have to miss the Rangiora Bowls Club Champs if he is to race at Greymouth Sreet races 2012. This would be a big ask for Kick. He sure does love his Lawn Bowls you know.
Ps err.....don't you have a NSR as well. Not that they are a little Gay aye.
pps Vanessa is a chick. What is it you call your NSR is it Alan?:rolleyes:
For Henk and Kel
Ps the Motor was less than a Good FXR and the total budget is less than one fifth of what one person has allegedly spent on his four stroke

[Henk]

For Henk and Kel
Ps the Motor was less than a Good FXR and the total budget is less than one fifth of what one person has allegedly spent on his four stroke

I can believe that, people have been rumored to spend stupid money on both four strokes and two. The reason I run diesels, even though I love two strokes, Is that I don't have the time or talent to develop five oil burners, and that is how many we have in the fleet at the moment. Someone commented to me a while back that I need to find a pit bitch, instead of being one. Fun to be busy though.

[2T Institute]

To tell you the truth I am not 100% sure if it is a NSR125 or a NSR150.
2t institute acquired it on Yahoo Japan.
It was dropped off in Austrailia and ended up in Tauranga.
It's there for some corrective surgery to fix the machining errors Honda made when they assumed it was going to be a road bike.:weird:

Most definatly a restricted NSR125 JDM. Are going to use a similar engine in a friends TAG 125cc Superkart. The early RS/NSR cylinders drop straight on. Having a blance shaft opens a world of opportunities.

[TZ350]

EngMod2T

I have been playing with the simulator to see what could be done with a ram tube on the inlet of the 3ex setup.

254232

160mm ram tube vis 105 Tube. Looks like opening a hole or shortining the tube 55mm at the cross over point would give a usefull power boost.

254231

3ex and 24mm pumper carb plus variable resonant inlet compaired to the 1ex setup (brown line) with the same carb open to the side without a header.

Previously the 3ex and 1ex delivered much the same curve and it was not untill I simulated a bigger carb did the 3ex deliver more power. Now with the header on the carb it looks like it will pass more air and deliver more power.

Who knows if the simulator is setup to handle resonant headers on the carb, but if it is, then this is very promising and points to the direction and dimensions of where to begin experimenting on the dyno with the inlet.

[Yow Ling]

Im sure this is way over 400hp/litre

Not sure of the STAs though

254278
254279
254280

254277