Exhaust I need some advice on an exhaust idea...

DJChrisp

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:unsure:My idea is to take a long piece of copper tubing and attach it to the muffler output and run it all the way back an inch past my back tire. How will this affect performance. Has anyone else done this. Any ideas theories or bonafried results would be great.
 
if its the size of the pipe on the 'muffler' i think it will cause too much back pressure and be detrimental to the motors performance. You can do similar with mufflers when they have expansion chambers connected to them, they are called "stinger" it is a length of pipe at the end of the muffler that can be slid in and to alter the engine's power characteristics, i doubt what you wish to do would have a positive effect however you need to have an expansion chamber for this too work.

KiM
 
the problem is that 2-strokes are VERY sensitive to exhaust sizing - length/diameter/volume. A change may help, it may hurt, may not matter, and may lead to the destruction of the engine after a while...
 
The use of copper may not be the best idea ever. Years ago I fabricated an exhaust system out of copper on a Honda. The exhaust noise coming from the end of the pipe was no louder, but the pipe resonated like a bell ringing. It was not at all a pleasant sound.
 
What about a larger dia pipe? Could that help with back pressure issues?

Rather than just asking questions and 'guessing' it would be better if you read up on how the tuned pipes (expansion chambers) on two strokes work and why they work then you will have a better understanding of the effects of pipe lengths on them. Cutting pipe and jamming it on the end of your standard setup isnt going to do anything for performance. Pipe length and also pipe shape is is critical to a 2 strokes performance. Adding an expansion chamber to a two stroke increases its power output by improving the volumetric efficiency. The engines uses the burn gases in the expantion chamber to assist in filling the cylinder for the next firing cycle. The size ie volume of the expansion chambers must be matched too the engine it is used on to get maximum performance.

Here's a diagram that will better explain the function of a tuned pipe for you

Arbeitsweise_Zweitakt.gif


By altering the 'stinger' you can alter the amount of back pressure thus flow back into the cyclinder, too much or too little back pressure will result in decreased performance. Its not as simple as 'whacking' a tuned pipe on a motor the pipe must be designed for the motor to get best results.


Best of luck

KiM

EDIT: appears the animated diagram above is no longer 'animated' strange... ?
 
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The idea wasn't necessarily to boost performance in any way but to redirect the exhaust to the rear of the bike without goofin' up my motor due to back pressure issues. Your post on the other hand was very informative and I'm sure it will come in handy down the road some day.
 
You can use 1/2" OR 3/4" electrical conduit (EMT) to fabricate a long pipe. I like to use the kit supplied exhaust pipe and flange, cut it from the muffler then use the EMT and fabricate a new pipe back to where I want the muffler to be. I use TIG but a wire feed, MIG, welder will also suffice. Conduit benders are cheap and available everywhere, Ace Hardware, Home Depot, etc. It takes a little practice to learn how and where to bend but after you get the hang of it you can fabricate a custom exhaust that will look good and function well.
Tom
 

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