ESE's works engine tuner

[yatasaki]

Husa, on Philous picture isn't aluminium, can say by colour.
ATAC, SAEC, KIPS, APTS etc all enough close to water space.
Or- enough thick/short piece would stand temperature as long as there is metal to metal connection to flange.
Why not complete pipe from Aluminium? We know that

[wobbly]

Two of the three cylinders on Freddie's triple 500GP had ATAC as per the pic.

[husaberg]

Husa, on Philous picture isn't aluminium, can say by colour.
ATAC, SAEC, KIPS, APTS etc all enough close to water space.
Or- enough thick/short piece would stand temperature as long as there is metal to metal connection to flange.
Why not complete pipe from Aluminium? We know that

That's casting but of iron or steel, no way that could be aluminium as exh. temp. on that bike is around Al melting point.
Only if double walled water cooled

your quote as i pointed out was incorrect to say aluminium would melt is incorrect.


The pipe doesn't get as hot as the exhaust gas does, as it gets washed by a fuel air mixture as well as being able to conduct heat away to the atmosphere and to the other parts. plus its not exposed to a constant heat.
if you used your logic you could not have aluminium pistons. Or air cooled heads or cylinders. as combustion and exhaust gas would melt both.
I don't wish to debate it as your assumption is simply incorrect. Or else the world would be full of melted atac vavles that have ZERO water cooling.

Two of the three cylinders on Freddie's triple 500GP had ATAC as per the pic.

I thought freddie had all three and the mortal plebs only got 2?
I was reading something on Freddie the other day with the first transatlantic match race he rode in he was lowering the lap record on the same bikes as the locals were running by over a second on tracks he only had done a few laps on.

[Frits Overmars]

That's not the squish angle; it's the squish edge angle; the squish angle is variable because of the spheric squish band.
Imagine the vertical line through the center of the piston dome radius. Then imagine a line through the center of the piston dome radius and the upper timing edge of the piston.
The angle between those two lines is 8,17° for a piston with a 54 mm bore and a 190 mm dome radius.

I was entering all the RSA data into my spreadsheet to test it but that angle didn't work and now I know why. So you use the tangent angle because it is the only angle you can mathematicaly true define.

My combustion chamber program needs to know the piston crown shape, but directly determining a piston dome radius is quite difficult, so the program offers two more options to answer that question. If you answer the radius question by entering a zero, the program will ask for the piston dome edge angle which is easier to measure,
and if you enter a zero again, it asks for the dome height. That is the true reason for mentioning the edge angle at all in the case of a radiused piston dome; it only serves to determine the dome radius.
Of course, if the piston has a flat or conical crown instead of a domed crown, the edge angle value is meaningful in itself for the squish area calculation.

Two of the three cylinders on Freddie's triple 500GP had ATAC as per the pic.

I thought Freddie had all three and the mortal plebs only got 2?

You're right Husa. The NS500 works bike had ATACs on al three cylinders; the RS500 production racer only had them on the two upper cylinders.

[yatasaki]

Looks like vespa 50 was going gp

[katinas]

Husa, on Philous picture isn't aluminium, can say by colour.
ATAC, SAEC, KIPS, APTS etc all enough close to water space.
Or- enough thick/short piece would stand temperature as long as there is metal to metal connection to flange.
Why not complete pipe from Aluminium? We know that

Like Husa write, headers on Philous picture (Honda NSR 500 98 or 99) is definitely made from light alloy and maybe even from magnesium (color is the same like on HRC magnesium cover and header as long as the engine and very close to gearbox in first picture)
When Honda stick to 112 angle configuration for NSR 500 engine from 1987 (Gardner) , they use long headers from light alloy on rear 1,3 cylinders until 2000. From 2001 (Rossi) and 2002 (Katoh) engines rear cylinders used with short headers, like on the front cylinders.

[F5 Dave]

I knew a chick who had a vespa. We went to a rally . She was a vegetarian. That's a non starter.

[TZ350]

Barn Find, or re discovery by the original builder. A 1972 Kawasaki F9 350cc BigHorn racer. https://www.cycleworld.com/custom-built-race-winner/

I am not looking to build a monocoque but I am looking to build a pre 72 racer using a Kawasaki 350/250 rotary valve motor. I want to race my friends who ride pre 76 Beneli 250 two strokes and pre 72 Yamaha twins. The plan is to get a rotary valve BigHorn 350 and sleeve the cylinder back to 250. Sleeving the big cylinder back should allow room for some modern porting trickery like axillary side exhaust ports and staggered large radius sweeping transfer ducts. A decent combustion chamber shape and modern pipe design with digital ignition. Running methanol which is allowed in pre 72 here. It should hopefully keep things cool enough so I don't have thermal problems with the plated alloy sleeve.

Anyway, if you can help. I am looking for Kawasaki rotary valve 350cc BigHorn F9 or F5 and/or 250cc Bison F8 engine/gear box parts and any info on the early BigHorn 350cc racers. If we can do a deal and the items are packed and addressed I can arrange collection from pretty much anywhere in the world.

[pete376403]

A 1972 Kawasaki F9 350cc BigHorn racer. https://www.cycleworld.com/custom-built-race-winner/

I am not looking to build a monocoque but I am looking to build a pre 72 racer using a F9 motor. I want to race my friends who ride pre 76 Beneli 250 two strokes. The plan is to get a rotary valve BigHorn 350 and sleeve the cylinder back to 250. Sleeving the big cylinder back should allow room for some modern porting trickery like axillary side exhaust ports and staggered large radius sweeping transfer ducts. A decent combustion chamber shape and modern pipe design with digital ignition. Running methanol which is allowed in pre 72 here should hopefully keep things cool enough so I don't have thermal problems with the plated alloy sleeve.

Anyway, if you can help. I am looking for Kawasaki F9 and F5 engine/gear box parts and any info on the early BigHorn 350cc racers.

\

Kevin Cameron built a 350 Bighorn at a time when the AMA allowed 350 singles to run against 250 twins. Ridden by Cliff Carr, it was featured in Cycle magazine. If you have back issues, it was in October 1971. Or get one here https://www.ebay.com/itm/Cycle-Magaz...-/254393627276

These days Harry Klemm is the goto guy for bighorns now, and of course Flettner right here.

I had a 72 F9 from new If I hadn't been a 18 year old who thought he knew more than the factory it probably would have served me a lot better

[husaberg]

\

Kevin Cameron built a 350 Bighorn at a time when the AMA allowed 350 singles to run against 250 twins. Ridden by Cliff Carr, it was featured in Cycle magazine. If you have back issues, it was in October 1971. Or get one here https://www.ebay.com/itm/Cycle-Magaz...-/254393627276

These days Harry Klemm is the goto guy for bighorns now, and of course Flettner right here.

I had a 72 F9 from new If I hadn't been a 18 year old who thought he knew more than the factory it probably would have served me a lot better

I have it saved somewhere ..........

Okay they are to big i will convert to smaller tomorrow

[Frits Overmars]

I have it saved somewhere ..........Okay they are to big i will convert to smaller tomorrow

Will these do?

[husaberg]

Will these do?


For Starters

you are going to make me do it tonight

[andreas]

Barn Find, or re discovery by the original builder. A 1972 Kawasaki F9 350cc BigHorn racer. https://www.cycleworld.com/custom-built-race-winner/

I am not looking to build a monocoque but I am looking to build a pre 72 racer using a Kawasaki 350/250 rotary valve motor. I want to race my friends who ride pre 76 Beneli 250 two strokes and pre 72 Yamaha twins. The plan is to get a rotary valve BigHorn 350 and sleeve the cylinder back to 250. Sleeving the big cylinder back should allow room for some modern porting trickery like axillary side exhaust ports and staggered large radius sweeping transfer ducts. A decent combustion chamber shape and modern pipe design with digital ignition. Running methanol which is allowed in pre 72 here should hopefully keep things cool enough so I don't have thermal problems with the plated alloy sleeve.

Anyway, if you can help. I am looking for Kawasaki rotary valve 350cc BigHorn F9 or F5 and/or 250cc Bison F8 engine/gear box parts and any info on the early BigHorn 350cc racers. If we can do a deal and the items are packed and addressed I can arrange collection from pretty much anywhere in the world.

https://www.klemmvintage.com/bighorntech.htm Maybe some is useful.

[jbiplane]

https://patentimages.storage.googlea...50062177A1.pdf
http://www.eta-engine.com/downloads/CWI

Seems simple solution from chainsaw world

[JanBros]

Frits, don't know if I have to congratulate you or ask you, looking at this graph :

is from my excel, entered all the RSA data (cylinder and head, and than calculated your FOS pipe. Red is standard FOS as by your fomula's with 57.5 BHP at crank and a speed of sound of 587m/s to get the same length as the tubo102.
green is a copy as good as I could get it within the limitations of my sheet (read : max half a milimeter here and there, and whitout the last baffle) with a Wobbly-duct at the front.

so : did you derive your FOS from the RSA pipe ? if, so, you did an excellent job
or is it an everlasting fine-tuning of your exhaust concept from the seventies, and than it is a outstanding-out-of-this-world job