I will never get the bigger rotor weight thing. By an XR if the 2 stroke MX race bike scares people. Am I the only person looking for lighter rotors? I had an '00, sent the top end to Eric to clean up, jetted, pipe and silencer(I copied a factory shorty silencer), tassanari and pv hitting as quick as possible. That is 1 250 I wish I never got rid of. And I am a card carrying Suzuki hater! On another note, my pos chinese pit bike, with a big azz flywheel, now has an itty bitty internal rotor, like modern mx bikes. Sweet, it runs like a 2 stroke, ripping top end, good pick up off bottom. The overbore will give the 2 stroke more bottom/mid. With the right set up, that can add to the top. This is all seat and rider response, no dyno data. Trails and mx set up, completely different. Choose your bikes accordingly, and modify to suit your needs. MX, more everywhere will do fine. That flywheel weight will take off the top mid hit, and smear it down low. Nothing like a 2 stroke that barks! On the stand barks, can be on the track also.