Expansion chamber on 4 stroke?

Drumbum12191 · Dec 12, 2011

Since my 2 stroke seized up on me I have got my hands on a new 4 stroke and it's great! The thing I don't care for is it's weak sound, especially compared to my friends' 4 strokes that have 2 stroke stock exausts which really make them ROAR! So I was wondering if I could take my old expansion chanber off my 2 stroke and put it on my 4 stroke. My goal is to get a nicer sound, I don't really care for performance (though it would be nice). My main concern is weather or not the expansion chamber would be damaging to the 4 stroke engine. If anyone knows I'd appreciate some advice, thanks!

diceman2004 · Dec 12, 2011

It won,t hurt your motor , but if the resonance is is a bad match it might give you less performance . It will do nothing to increase the performance on a 4 stroke .
you would be best off making a pipe with a strait screwin type lawnmower muffler .
You will probably be happier with the sound of a longer pipe .

But be warned .. if you have a long pipe coming off the motor .. do it in a way that you will not break it off accidentally , because you could really mess up the head .

petrochico · Dec 12, 2011

How would I configure a long straight pipe with a lawnmower muffler?
I have a 4 stroke and want to try that. Where to get parts?
Thanks....

DaveC · Dec 12, 2011

3/4" EMT conduit. Start with it long then start cutting it off a little bit at a time, like an inch at a time. Expansion chambers work different than what your after. A 4 stroke wants a properly long pipe that's tuned to an exact length. Like on a hedder for a car. All you can do is seat-of-the-pants testing to find out what's too short or too long but you'll feel when it's right. You might go past and make it too short but EMT is cheap and benders are cheap as well or you might find someone with one you can borrow or even an electrican with a bender. .trk

GasX · Dec 12, 2011

check out the thread on Phantom Bikes on Jay Leno's garage. They sell a straight pipe and you can hear it in the video - sounds great!

hawaii_87 · Dec 13, 2011

Go here. Shop Phantom Bikes and look in the right hand side.

My friend opened up a 4 stroke shop and there was a custom cruiser in there with this pipe and it sounds like a mini harley with big cajones. Now the site is a bit messed up I think they are re-doing it. But the pipe is worth it.

scotto- · Dec 13, 2011

Expansion chambers are designed for the port timing of 2-strokes. 4-strokes have valves and don't rely on the ports for timing or actually tuning.

Straight pipes work well on 4-strokes

dnut

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Expansion chamber on 4 stroke?

Drumbum12191

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