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2 Stroke with Dual Silencers?

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Hey Guys

 

I was watching a video on Youtube about 2 strokes and I noticed a Custom CR250 that had 2 silencers on it.

I was just wondering if anyone knew how the exhaust system would work. If you could just use 2 slip on silencers and an expansion chamber, or if the exhaust would have to be custom made.

 

Cheers

 

 

Screen Shot 2014-04-21 at 6.21.29 pm.png

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That's a CR500. You can tell by the shroud that says "MX 500AF" in your pic.

 

Google "500AF dual exhaust" for plenty of pics of different bikes like this. Seems the 500 guys like you reuse the CRF250's dual silencers when using the chassis from one for a swap.

 

It's purely for looks. One could likely outperform it with a single silencer, and twin silencers definitely isn't saving any weight.  I personally think it's pretty dumb, but I prefer function over form.

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The only time you'd actually WANT 2 silencers is when you're running a twin two stroke. But you'd have 2 expansion chambers to go with the silencers. The Yamaha Banshee/RZ350 engine is a twin 350 2-smoker.

For dual exhaust on a single cylinder, you'd be looking at a custom exhaust that would yield no benefit for performance.

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As I recall from reading my Gordon Blair, the stinger diameter is more important than its length is.  The primary purpose of the stinger is to prevent the outflow of exhaust well enough to create a strong pressure wave back to the exhaust port, but also to relieve the pressure within the pipe for the next pulse, so it is mostly the net diameter of the outlet point in the convergent (rear) cone that matters. 

 

Dual stingers, whether they're two completely separate pipes, or they split after a single outlet, are not apt to give any benefit beyond possibly being quieter, probably would not cost much power at all, either.

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Dual stingers, whether they're two completely separate pipes, or they split after a single outlet, are not apt to give any benefit beyond possibly being quieter, probably would not cost much power at all, either.

 

1979 My SWM 250 with  disc valve Rotax motor had a single muffler with twin outlets. Probably to allow greater absorbtion silencing to keep the noise down. It was a *lot* louder once the motor was nailed in to a Morini frame for singles class road racing and I grafted a TZ750 race silencer on the end of the expansion chamber to replace it. Went quite well though.

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