I'm j opening a new topic for drag bike mike's question so that finshammer's topic doesn't get too cluttered.

Mike,s question:

Zevenenergie, taking that little moped from an 8K redline to 13K redline must have been fun.  Do you think it was choked off a bit with that 8mm carb?  That's like the size of a pencil.  I've got carbs that big on my model plane engines.  To run the engine up that high, did you have to switch to thinner piston rings?

I increased the cc to 73 and used a piston with thinner rings, but that isn't really necessary. This little engine went from 4 hp to about 15 hp and ran 100+ km/h with a variator drive and the lifespan is not really great.

And yes, that 8mm is a significant obstacle, but the biggest power gain came from the scooter exhaust I had installed. A 2-stroke is very sensitive to the dimensions of the exhaust.

If you put a standard exhaust on a 50cc 21hp 2-stroke racer, it only has about 6 hp.

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