[Steve@Motowest]

You're on right track with the small rings, that's called a cone pipe. That's all we had back in day and that's how the best pipes are still made today.

Back then, long before there were published formulas it was all trial and error. I remember watching Daryl Bassani and Donnie Emler beating and banging and sweating over pipes seemingly forever, always trying to make them better.

Now the easy way is to start with an existing pipe and just keep modifying it to produce the power you want. The Motowest pipe went into production after about three days of testing and only 2 prototypes being built. Once you have a working prototype you then use it to make the stamping dies and jigs to go into production with.

Today the specs have become so standardized... Be it mx or enduro or road racing, for any engine size and intended usage there's about 2 or 3 standard set of pipe measurements to choose from. Just twist and turn those measurements around and through the motorcycle of your choice and you have an exhaust system.

Although the science of 2-stroke exhaust design still lives on, the art of 2-stroke exhaust design has been all but lost. It's a bit of a shame really.