That engine base can turn 12'000 rpm's w/ the stock crank. so fear not. Look for an aftermarket intake system, as most people will replace the stock air box. Also the variator/clutch may have been replaced. The stock parts are non descript, plain looking. Aftermarket parts will have their name on them. You can check the rollers/springs while in there to see if they have been replaced, or if they need replacing. The last thing would be the drive belt. Most people will replace the factory Bando Belt w/ a Malossi Kevlar Yours should measure 17mm across the top if it is still good. 18.5mm is new, and 17mm is the limit. Good luck w/ the scoot. It is my personal favorite model.