I don´t think the R1 and the Honda engines are the best examples, since it´s cranks and rods are set on metal bushings( I think it´s the term) which clearences are filed whit oil on an higher pressurised oil pump, plus, being 4 cilinder engines makes the crank more balanced due to the firing order, opposite to the big stroke on the thumper on just one bearing.but then, it´s just my thought:excuseme: Keep in mind here that most of the guys on this forum dont race. Some dont even do any mx. When you are not being super hard on the motor it will last a long time. You said you were dirt track racing right? Personally I think that is one of the hardest things you can do to a dirtbike motor except maybe running it on road america with stock gearing. not exactly flattrack, but supermoto. maybe i´m riding on a bit stessing conditions and you guys are not so much... could also help if you tell me how do you ride.