Another sled exhaust question

[Jay1823]

I'm gonna post pics later to make my question clear but i'm mounting my Rotax in my Pilot and the biggest problem is the exhaust. My stock manifold just straight out which is a problem. My question is on the pipe itself. I know i can't mess with the expansion chamber and i really don't need to but i would prefer to modify from where it goes from the manifold to the exspansion chamber, that 180 degree area. What i want to do is make my own manifold to suit my needs for room. I'd like to chop the pipe right in the middle of that 180 degree turn. I haven't taken accurate measurements yet but it may lengthen the whole run maybe 2-3 inches. Any problems with my plan?

[Bugpac]

the length is a big tuning factor, how far the chambers start is from the piston...

[bdkw1]

Lengthening it will move your power band down.

[Jay1823]

Now that i made some quick drawings i think i can keep the length equal pretty easy, i'll just make a mark on the exhaust where the chamber starts and take a length measurement and go from there. 4 *strokes are so much easier, throw on a header and call it a day .

[greasemnky]

Just run the pilot exhaust for now. Granted, your going to loose about 10% of the power, but so what. You've got plenty. Plus, its already been done before, and cuts down on the fabricating etc. You can always go back and build a pipe.

[Jay1823]

I don't have a Pilot exhaust unless you have one, all i got from bug was a frame and a tranny, das it.

[Bugpac]

your nuts, your gonna loose far more than 10% of the power...that pipe is made for a single first of all, you cant make power in a 2 stroke unless it can breath...Dont listen to bill jay, hes into some florida crack or something...

[Jay1823]

Believe me i don't listen to Bill when it come to engine stuff, i know way more than he does . 2 strokes i just no less about since i've never had one until recently, i was poor as a kid, never got to have fun of off-raod toys . But i have been doing alot of reading trying to learn as much as possible, that's why i ask all these questions. But ask me about turboing a Honda motor and i'm your guy. Here's my very quick and crude MS paint drawing. The top is the stock exhaust setup, it probably stick out a good 14-18 inches so it would definately hit my seat. So if i can measure the length where i put the red lines and make it equal i should be good correct?

[Bugpac]

thats the problem, in your picture, you have to have 2 red lines out of the v, cant count were they cross as one, in the second picture, you have one way shorter than the other, if you make it curve out to get length it will alter the back pressure...what about turning the y to point down, then slice the expansion chamber were needed and rotate it so it doesnt rotate straight up?

[weasel]

This is the big problem with these engines,,the "lead-in"pipe section just has to go straight for it seems like a mile! The "Y" will be just as important as any other section of the pipe, I wouldn't change that
part, but, the lead-in section just after that could be cut in angled sections to create a turn to get outa there sooner. The original length will have to be followed with painstaking care and you may need to get friendly with a "tin bender" (sheet metal man) to cut and roll you some stock to work with.
I know, it's an awful task, but theres just no other way to do it

The sonic wave in the pipe won't have any problem navigating these sectioned bends, check the Aaen pipes.