ESE's works engine tuner

[Dutch Fisher]

Pictures attached, but it seems I am not capable of doing the translation.

Translated, but any others you want translating will have to be 1920x1080 x 600dpi, easier for the OCR

[Dutch Fisher]

Add some drawings from "Racers" that can be helpful about YZR, NSR "Crank-angle-firing-forces".

https://www.kiwibiker.co.nz/forums/a...3&d=1533200780


Looks like the big bang was designed to have zero piston acceleration on the bottom cylinder while the top cylinder was on max deceleration (TDC), poss. 50% primary on the crank wheel married to 50% on the balancer ¯\_(ツ)_/¯

[Dutch Fisher]

Spaan planned to produce his own cylinders (which would have had all the characteristics of Honda cylinders) but when Suzuki got wind of it, they insisted that the factory would take care of that, if Hans would only provide the drawings. Nothing ever happened,

Likely fell to unwritten Japanese rule of not copying each others designs.

.....but in any case Suzuki did not lose face quite as much as Yamaha did, when Harald Bartol made them pay him for putting shameless Honda-copies on the Yamaha TZ125 (and on the 125 cc Derbis. And on the 125 cc and 250 cc KTMs).

Not forgetting the money Bartol received from the eyeties for the Gilera GFR250, with that perticular unit sporting some very Yamaha looking clyinders.

[Frits Overmars]

https://www.kiwibiker.co.nz/forums/a...3&d=1533200780
Looks like the big bang was designed to have zero piston acceleration on the bottom cylinder while the top cylinder was on max deceleration (TDC)

Yep.......

[Norman]

Yes, I am glad the pictures are not in Japanese, but I would not be surpised if Mr. Dutch Fisher could have fixed that too!

Never mind Norman, as long as the pictures themselves are in English .
I encountered this engine in the Molenaar GP-team where Hans Spaan tried to bring it on par with the 250 cc works Hondas on which he had been working previously. The Suzuki suffered from a lack of power and an overdose of complexity. Each cylinder had an exhaust power valve with no less than three blades, called SAEC, and an ATAC-type resonance volume, called AETC, which brought a lot of unwelcome heat in the cylinders.
Spaan planned to produce his own cylinders (which would have had all the characteristics of Honda cylinders) but when Suzuki got wind of it, they insisted that the factory would take care of that, if Hans would only provide the drawings. Nothing ever happened, but in any case Suzuki did not lose face quite as much as Yamaha did, when Harald Bartol made them pay him for putting shameless Honda-copies on the Yamaha TZ125 (and on the 125 cc Derbis. And on the 125 cc and 250 cc KTMs).
The best thing of the Suzuki works engines were their pistons, consisting of a light-alloy base material with embedded ceramic fibers. Spaan claimed they lasted ten times as long as Honda pistons.
Attachment 337907

[husaberg]

https://www.kiwibiker.co.nz/forums/a...3&d=1533200780


Looks like the big bang was designed to have zero piston acceleration on the bottom cylinder while the top cylinder was on max deceleration (TDC), poss. 50% primary on the crank wheel married to 50% on the balancer ¯\_(ツ)_/¯

I agree with the first bit but not the second.
MY take is the two lots of 50% are the balance factor on each crankshaft, ie half from the opposing piston and half from the counterweight .to achieve 100% primary balance
the balance shaft is for secondary forces, it was added for the two up crank 180 degree crank used the last two years before the big bang. Its main function is the jack-shaft to change the direction of the engine to lessen gyro.
If my theory is correct I dont believe the big bang even really needed it.

Ducati twins have V-angle 90 degrees. This uniquely makes it possible to balance a 90-degree twin with counterweights of 100 percent of one piston’s shaking force. Here’s how it works. At the front cylinder’s TDC and BDC, the heavy crank counterweights cancel the front piston’s shaking force. But at 90 degrees and 270 degrees, those same heavy counterweights now cancel the TDC and BDC shaking force of the rear piston. In other words, both primary piston shaking forces are 100 percent balanced,

[jamathi]

Never mind Norman, as long as the pictures themselves are in English .
I encountered this engine in the Molenaar GP-team where Hans Spaan tried to bring it on par with the 250 cc works Hondas on which he had been working previously. The Suzuki suffered from a lack of power and an overdose of complexity. Each cylinder had an exhaust power valve with no less than three blades, called SAEC, and an ATAC-type resonance volume, called AETC, which brought a lot of unwelcome heat in the cylinders.
Spaan planned to produce his own cylinders (which would have had all the characteristics of Honda cylinders) but when Suzuki got wind of it, they insisted that the factory would take care of that, if Hans would only provide the drawings. Nothing ever happened, but in any case Suzuki did not lose face quite as much as Yamaha did, when Harald Bartol made them pay him for putting shameless Honda-copies on the Yamaha TZ125 (and on the 125 cc Derbis. And on the 125 cc and 250 cc KTMs).
The best thing of the Suzuki works engines were their pistons, consisting of a light-alloy base material with embedded ceramic fibers. Spaan claimed they lasted ten times as long as Honda pistons.
Attachment 337907

Bartol also STOLE the fairing models from DERBI, and used them on the KTM.
They were made for DERBI by Porsche.
And of course paid for by DERBI.

Later, while testing the RSA engine in 1996 it was discovered that this fairing had a very negative effect
on steering, especially at high speeds!!!
Only good in a straight line...…The bike only wanted to go straight....
Shame on Porsche!!!

And Yamaha also copied the Honda cylinders on the 500/4's, helped by Bartol.
As did Yamaha-France for their 250's.
Yamaha even published an SAE paper about this....
Really SHAMEFUL!

Maybe Honda, just like Aprilia, liked to SELL a lot of pistons.
At Aprilia this was bringing in lots of cash----
80% gains on the price, or more!
Only few people knew this.....

[Dutch Fisher]

... poss. 50% primary on the crank wheel married to 50% on the balancer

MY take is the two lots of 50% are the balance factor on each crankshaft,

We are saying the same thing..


At the risk of the blind leading the blind (kinematics are my weakest topic) here's a theory.


Using the formula I stated earlier (2xAv)-180) the 112* comes out spot on at 44* pin offset.
That means primary balance is achieved right there, as noted by the zero piston accleration on the bottom cylinder and max decel on the top cylinder (TDC)

The fly in your soup is the secondary forces are having a party in a wasps nest and buzzing away merrily.
I've modded the pic and added the sum of inertia force lines of the secondary in yellow.
Now it seems Honda has approached this problem (likely 2 mins on the back of a cigarette packet for them) by reduced the crank balance factor to 50% and added that other 50% to the balancer so maintaining primary balance. This has allowed them to use a good % of the rotating interia of the balancer counter weight (thats counter-rotating) to offset a fair degree of that untamed secondary inertia force.
The counter force angles are not absolutely in-line while at their respective peaks, but it looks like the level of vibratory forces is reduced to the point that its ok to solidly mount the crankcase into the frame.

[husaberg]

Loads of RGV500 pics
including inside the crankcases
https://www.kiwibiker.co.nz/forums/a...p?albumid=4848

[jamathi]

Likely fell to unwritten Japanese rule of not copying each others designs.




Not forgetting the money Bartol received from the eyeties for the Gilera GFR250, with that perticular unit sporting some very Yamaha looking clyinders.

It is well known that Gilera got Kocinsky's bike from Yamaha after John won the championship on it.
Gilera did not excactly improve it, stupid fools....
And even the great Bartol failed miserably....
They spent millions for nothing!

[katinas]

All is very interesting, thanks.

Looks like RGV 500 piston skirt cut at C is big like on street RGV 250 and at the same level like main side cuts. Street RGV 250 piston skirt looks very fragile, but is it made for better flow acceleration through C port, when piston at TDC , or for less obstructed way in/out crankcase when piston at BDC.

Add RGV 500 XR78 1989 cylinder drawing, and probably this was first decade when was discovered that A higher than B work in good way for wider power range, but really I don't know. Ex duct with small step and then two sections before pipe.

Looks like on Honda RSW 250 2009 cylinder duct and spigot dimension gradually changed before pipe without step.

NSR 500 crank-sprocket chain.

[TZ350]

Suzuki on RGV 250 XR96/98 used Mikuni with Yoshimura type multiple jet nozzle and in 1995 on XR95 they tried EFI with 40mm body (not on the factory "Lucky ..., but on JAJA team's engine, maybe in All Japan Championship).

Chambers has a 24mm version of one of those carbs on his F5 Suzuki RG50 Bucket, seems to work Ok.

[katinas]

Chambers has a 24mm version of one of those carbs on his F5 Suzuki RG50 Bucket, seems to work Ok.

Interesting how better atomization influence two stroke piston cooling at high revs.
Yoshimura developed this for four stroke GSX-R SBK from 1988 and was launched in 1992.

[Norman]

The steps and contracting exhaust ducts; could it be that they help such that the exhaust gas does not heat up the duct walls as much. The flow get's separated from the walls after the step? The air-fuel slug going out in the exhaust port will be less heated up? (As the exhaust port opens there is a lot of tubulence and pressure which enhances forced convective heat transfer a lot)

All is very interesting, thanks.

Looks like RGV 500 piston skirt cut at C is big like on street RGV 250 and at the same level like main side cuts. Street RGV 250 piston skirt looks very fragile, but is it made for better flow acceleration through C port, when piston at TDC , or for less obstructed way in/out crankcase when piston at BDC.

Add RGV 500 XR78 1989 cylinder drawing, and probably this was first decade when was discovered that A higher than B work in good way for wider power range, but really I don't know. Ex duct with small step and then two sections before pipe.

Looks like on Honda RSW 250 2009 cylinder duct and spigot dimension gradually changed before pipe without step.

NSR 500 crank-sprocket chain.

[TZ350]

Interesting how better atomization influence two stroke piston cooling at high revs.

Yes, good point. maybe not so much piston cooling, might be a problem.....