Kawi2strokes.com Forum

I haven't seen this on bikes yet: http://www.youtube.com/watch?v=hOYvFgGqjUg&feature=related

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If it surges, that's normal, upshift.

I know it's a "tech" thing, but in reality, on a motorcycle I don't see the necessity, plus you would have to have a straight header section. (which is difficult) And then you would have to be on a very long straight to use it, and most street motors will rev to their top RPM anyway.

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Twist the throttle, tilt the horizon, and have a great time. What triples are all about...........

Kevin Cameron and I always used to speak about the need for an "active" expansion chamber for two stroke racing. We thought of things like a camera aperture type of reducer at the exhaust flange, sliding center sections and a lot of other things we never had the funds to do.

Yamaha did this with the power valve in two strokes, and the EXUP valve on their street 4 strokes.

Honda Racing Corporation did it to a few of their NSR500 racers, by adding a water tank to the bike, with a 3/4ths gallon volume, and a computer driven pump, to inject water vapor into the primary pipe. Effect, the steam created an offset of volume in the head pipe, changing its flow rate, making the engine think the exhaust system was of smaller dimension at lower rpms, for more low speed torque production.

Many different ways to attain the same basic/similar results.

Interesting about the water. I've mentioned it before, but I saw an inboard hydroplane with a Polaris sled engine that injected water into the expansion chamber (2 into 1) to get the boat on plane, and then ran the chamber dry once it got up to speed. The driver said until they added that feature, they couldn't get on plane at all.

It seems like with a sliding center section you could use steeper cone angles for a peakier chamber, and then slide the peak around to match engine RPM. In other words, the chamber design would not have to be compromised to give a broad powerband.

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If it surges, that's normal, upshift.

Those were the hot ticket on 60's enduro karts, slippy pipes. Sorry if I'm being redundant.

I looked into it when Don started working on that 3 into 1 pipe... About 6" to change the peak hp by 2000 rpm... That's allot of sliding while fitting under a bike! Not so bad with one pipe but three would be a challenge for sure...

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http://kawatriple.com/wtf/

Anything can be done with enough time, money, and desire. Unfortunately, I doubt if I have enough of any one of those to start working on a 3-slip-pipe system.

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If it surges, that's normal, upshift.

I had a 84' YZ125, first year of liquid cooled and had troubles with that power valve. When it did work, it was a totally different bike.