Two-stroke performance tuning?

[F5 Dave]

. . . .

The sad thing is I never was able to finish posting my results.

The people who where taking a serious interest in that are the ones that miss out.

As a result I won't be sharing my findings on this site.

Or for correct blowdown times either.

. . .

Oh boo hoo. Won't someone think of the children.

Melodrama of your own choice.

- - - -

Post 279 almost sounded stable & reasonable. Who the hell wrote that post?
The above post shows your complete Jekyll & Hyde persona. SS90 Vs Neil.

If you had written like that from the start no one would have thought, Gee that chap is a complete & utter wanker & none of this would have happened. There may have been some challenge to some ideas & healthy discussion, but no outright disrespect on both sides.

But I'm sure your attitude has & continues to get you into fruitless arguments so I don't expect you to learn or modify your behavior one iota.

[SS90]

Oh boo hoo. Won't someone think of the children.

Melodrama of your own choice.

- - - -

Post 279 almost sounded stable & reasonable. Who the hell wrote that post?
The above post shows your complete Jekyll & Hyde persona. SS90 Vs Neil.

If you had written like that from the start no one would have thought, Gee that chap is a complete & utter wanker & none of this would have happened. There may have been some challenge to some ideas & healthy discussion, but no outright disrespect on both sides.

But I'm sure your attitude has & continues to get you into fruitless arguments so I don't expect you to learn or modify your behavior one iota.

Healthy discussion is fine, constant childish nonsense is another.
Have you even bothered to read every post in this thread, or do you just chose to ignore the antagonism from the ESE "team"

Well, let's just see how the scroll diode thing goes, 1971? I can't imagine why GP teams don't use them today.

It's interesting to read about such history of development, but who uses it today/when did it see production?

[Skunk]

Well, let's just see how the scroll diode thing goes, 1971? I can't imagine why GP teams don't use them today.

Even I can see why GP teams don't use scroll diodes... Can you SS90? I'll explain it for you if you can't can tell me why they don't. I'll give you a clue - it's not because they don't work.
I can even guess why it's not used in production bikes. Can you?

Get back to me when you've finished your study and I'll mark your answers. There's a good boy.

If you don't like my tone you shouldn't have used it on me.

[Skunk]

Still studying the answer huh?

[B.Crump]

I have two (and I've watched TZ350's thread with interest) - one is a cast iron rotary Kawasaki F6 and the other an alloy rotary Suzuki TF125. At present both are in the barely running stage so a little early to post specs. But I will.

i am trying to get as much as possable out of a tf125 im just doing a top end rebuild with 0.5mm ova size piston i have modafyed a kx125 exorst to fit and cant wait to try it do you know of any other mods i can do? cheers

[F5 Dave]

You definately ned to polish the head, try stripeing it with striper & then polishing it with sandpaper & worn out paper until it is as shiney as possible, even deep into the fin grooves then tri autosoul polish

[koba]

i am trying to get as much as possable out of a tf125 im just doing a top end rebuild with 0.5mm ova size piston i have modafyed a kx125 exorst to fit and cant wait to try it do you know of any other mods i can do? cheers

Take it out of the gokart.

[SS90]

You definately ned to polish the head, try stripeing it with striper & then polishing it with sandpaper & worn out paper until it is as shiney as possible, even deep into the fin grooves then tri autosoul polish

Combine the above technique with a copper combustion chamber (all the rage in high performance two stokes, perhaps even a copper finned base gasket) and exhaust pipe and port specs from a 1970's book, and you got your self a weapon.

Either that, or you could read a book called "the two stroke tuners hand book" By Gordon Jennings.....

It's a really good place to start, many top tuners have recommended it to me, it is well written, and while SOME aspects are dated, if you read it carefully, it is a little "ahead of it's time"

[B.Crump]

thanx ill try thos things out and see how it goes cheers

[B.Crump]

has any one supercharged a 2 stroke?

[koba]

Yup, Two stroke diesels have to be supercharged.

[Yow Ling]

has any one supercharged a 2 stroke?

DKW and NSU had them

[Skunk]

DKW and NSU had them

Mine's supercharged - it has a chamber.

[SS90]

Mine's supercharged - it has a chamber.

I'm not too sure that I would subscribe to an expansion chamber being a "supercharger"........

A supercharger is essentially a compressor that forces air into an engine......An expansion chamber doesn't do this.

Are you referring to the expansion chamber "evacuating" the cylinder to below atmospheric pressure, assisting the positive pressure from the crankcase below, thereby increasing the delivery ratio?

Because that's not a supercharger.

HOWEVER.....

This very effect (and correct understanding of which) brings up an important part of expansion chamber design.

There are plenty of computer programmes available that will design a pipe for you, using just port time areas,RPM intended etc.

My experience is that all these programmes that only require a small amount of data (specifically in relation to exhaust port only) return essentially the same expansion chamber..... (dated)

Obviously, the more you spend on the software, the better the expansion chamber you end up with....but you have to "answer the right questions" this software asks......it's quite complicated.

There are alot more factors you must consider when designing an expansion chamber.

That is the difference between an expansion chamber designed in the 70's, and one designed recently.

It was mentioned (F5 Dave) that an old designed cylinder (I would personally make the broader statement of old designed "engine" opposed to just "cylinder"), does not work ideally with a "new" (modern) pipe design.

That is 100% correct, and there are good reasons for it.

Think of it as trying to connect your 1981 Atari to a flat screen, and expecting it to be a PS3

[Buckets4Me]

A supercharger is essentially a compressor that forces air into an engine......An expansion chamber doesn't do this.

Are you referring to the expansion chamber "evacuating" the cylinder to below atmospheric pressure, assisting the positive pressure from the crankcase below, thereby increasing the delivery ratio?

Because that's not a supercharger.

I thought that the chamber also helped by sucking fresh charge into the chamber then forcing it back into the cyliner using the presure wave from the exaust bouncing of the rear cone of the chamber ???

well I guess I was wrong