ESE's works engine tuner

[shnaggs]

I guess the real way is to just build one and test it. With mine I was looking at taking the bleed off from the center section of the chamber anyway, so the 'flap' didn't need a hole in it. Shnaggs, have you tried this idea?

Flettner, No I have not tried it yet, just a thought scrambling around in my head (I have too many of them). Although, I should just get another pipe to hack apart and see how she does. I tried some quick sims on engmod and saw a slight benefit, but not enough to get excited about....but then again, I think if its executed properly, I think it could work really well and in conjunction with your RV it should work even better.

[SwePatrick]

A question for someone..

My kx250(212cc) cylinder had the exhaustguillotine hanging down into port and as it is an dragracing highrevving machine i decided to delete it and only let the KIPS control the Aux exhaustports.
The question is: how important can it be to get a totally smooth exhaustrunner?
In picture below you can se there are some 'ridges', but nothing that protrude into the port.

So i welded a plug into the 'hole' for the guillotine and grinded it as smooth as it allows without going nuts in the port/runner.
I did this before i put the new liner in to ensure everything stays round etc etc.

[Larry Wiechman]

Is Viton the preferred material for O-rings used to seal liquid cooled heads?

[Haufen]

Is Viton the preferred material for O-rings used to seal liquid cooled heads?

Viton would be a bit over engineered to just seal the coolant to the atmosphere, as almost any material will cope with lower temperature coolant. But if you're talking about domes / combustion chambers or exhaust flanges, then it might be beneficial indeed.

[wobbly]

Viton is the material of choice for the inner ring where it seals the chamber to the cylinder top.
But around the outside where it seals only water ,normal O rings are fine.

[Flettner]

I've have a viton O ring in my air cooled 350 head for over 70 hours. Never leaked.I might be wrong I think its a silicon Oring
Both good for high temps

[FastFred]

Thomas is really keen to CC the engine. The best way would be to take the engine out of the bike so it can be levelled up and CC’d through the sparkplug hole.

Looking at the picture it looks like TeeZee was using an "O" ring for a head gasket on his air cooled engine from the very beginning. Maybe Thomas suggested it to him. Pretty sure someplace he said it was a Viton "O" ring.

...

[lodgernz]

Looking at the picture it looks like TeeZee was using an "O" ring for a head gasket on his air cooled engine from the very beginning. Maybe Thomas suggested it to him. Pretty sure someplace he said it was a Viton "O" ring.

...

Looks more like a copper ring to me. Often used in racing foul-strokes.

[F5 Dave]

Well Fred would know being Robs right hand
Man

Viton is dark green almost black. Used it for decades as head gasket. Even a smear of red silicon rtv will suffice as outer gasket. Use easily machined round groove on inner and rtv on outer. Never had a failure in 20 + years.

[TZ350]

Yes, Viton, there are different grades (different colours) but I just used a bog standard (black looking) Viton O ring as a head seal on the air cooled motors. No failures, only unfortunate moment was when I tried a proper head gasket and still had the O ring in place. 30 hp on the dyno and the head gasket failed never had a problem with an O ring.

Well that did not go so well, spat the head gasket.

[1948rod]

I have been made aware of dangers of Viton when heated or burned as in fan belts on burnt cars being dangerous. Since then I don't handle the used o rings in my exhausts. Possibly over cautious. If one was given a clean sheet to build an engine possibly wobbly on a new Kz would it be possible to extend the exhaust side of the cylinder especially the ex. Nozzle to a length that could house the required shape and be cooled the full length for cool charge to re enter the cylinder.

[MENTAL490]

Concentrated H2O2 was used in the V2
Jet packs were also H2O2.
The kiwi version is powered by four CR500's

Damn thats a bit more ambitious than my join 2 cr500s and throw it into a gsxr250 frame i had.

[MENTAL490]

Viton is the material of choice for the inner ring where it seals the chamber to the cylinder top.
But around the outside where it seals only water ,normal O rings are fine.

Viton has no oil products in it, i used it a lot in designs for BOC oxygen parts its pretty good up 200c but no good under -60c but some how i dont think it would get that cold here.

[jamathi]

I have been made aware of dangers of Viton when heated or burned as in fan belts on burnt cars being dangerous. Since then I don't handle the used o rings in my exhausts. Possibly over cautious. If one was given a clean sheet to build an engine possibly wobbly on a new Kz would it be possible to extend the exhaust side of the cylinder especially the ex. Nozzle to a length that could house the required shape and be cooled the full length for cool charge to re enter the cylinder.

Lengthening the exhaust duct and cool it very well is one of the things I regret not having tried!
I had the idea in 2007, but did not try it because I was planning to retire...
Almost certainly it will give e good power improvement!

[jasonu]

Well Fred would know being Robs right hand
Man

Viton is dark green almost black. Used it for decades as head gasket. Even a smear of red silicon rtv will suffice as outer gasket. Use easily machined round groove on inner and rtv on outer. Never had a failure in 20 + years.

I used viton o rings for inner and outer head seals in the water cooled KERG. They were a red/tan color. I replaced them around twice a season just because. Never had a failure.