can you use a 4 stroke muffler on a 2 stroke the pipe diameter on a 4 stroke pipe is alot smaller tahn the manifold diameter would this cause problems with back pressure etc...????

You can do anything ... but why would you want to?

A tiny 4-stroke pipe will hurt your performance and likely not give you much of a noise reduction. You would probably be better off running no pipe at all.

Cheers,

Andre

Also, wouldn't you have trouble mounting the 4-stroke muffler on a common two-stroke? Most two stroke exhaust ports are wide and flat, while 4-strokes usually have a simple hole.

And yeah, why would you want to?

Well, any pattern plane using a tuned pipe or 4-stroke muffler (long pipe such as hatori, ES carbon, Asano carbon etc) also need headers (usually an aluminum tube with exhaust port adapter together) to connect between the pipe & the engine.
One can use a 4-stroke muffler (pipe) with a 2 stroke engine. These mufflers aren't tuned, but to reduce the noise level. It will not hurt the 2-stroke, but may reduce some power. a 3M 170 can still use a muffler not a tuned pipe, so as other large 2-stroke.

To use the 4-stroke pipe with 2-stroke, you will want to minimize the back pressure by enlarging the inlet of the 4-stroke pipe (aluminum pipe can be done). Another way is to use a full length 2-stroke header with a soft silicone coupler that fits tight on the muffler, but expands enough to fit on the larger outlet diameter of the 2-stroke header.

You can also order a custom header with your desired outlet diameter from Karl Mueller [[email protected]]. I got a beautiful wrap around header for my 91SX-H which I am using with 140 size tuned pipe. You can ask him for different diameter.

Hope this helps,

IP