Brian Roth; If you look at any production 2-stroke motorcycle, tuned pipes are standard equipment. It has to do with fact that 2 strokes are different from 4 strokes in that they take their intake charge at the same time they are expelling their exhaust. Without a pipe part of that intake charge follows the exhaust out of the combustion chamber and out the exhaust pipe. A properly sized pipe with the correct pipe/header length will reflect a pressure wave back toward the exhaust port to push back that part of the intake charge so it can take part in the combustion/power making process. The overall size of the pipe must match the displacement of the motor and the overall length of the pipe/header combination must match the desired rpm range of the motor, hence the term "tuned pipe". It is also important to note that pipes do not always produce top end power at the expense of low end pull. It is true that if the rpms drop too low the motor will go "off the pipe" . But if properly tuned, a pipe/header combo will give substantially more power across a usable rpm range than a standard muffler. As an example, in kart racing a popular class used to be Yamaha Kt-100 cc motors. Two classes using these motors were allowed, one using a pipe and one using a can muffler. The piped motors produced about 16 hp and the can motors about 12 hp with much less pull out of the corners. In summary, tuned pipes will always increase the power to weight ratio of a 2 stroke motor over a usable rpm range if you are wiling to put up with the up front cost of a pipe.