What would symptoms be for a bad rotor? Weak little spark? Hard Start? I got a bike that simply falls all over itself at the top end. Could a weak rotor do that? Got an NT on it. Tweaked and fussed and messed with it all last year. I run a pocket bike exp chamber exhaust, I stuffed a male battery terminal cleaner into the end for positive back pressure. It Does run better under a load but still seems to fall flat when I wind it up on level ground. Hmm.. Food for thought. Thanks Crassius.
a weak rotor has a weak spark at low speeds - expansion chambers can make more power, but it happens only at certain speeds - the reflected wave always takes same time to reach cylinder, so only scavenges at the RPM that has that amount of time between firings