A stock moped engine is very lightly stressed, even when ridden at full throttle all the time, they will last practically forever. It's when you start modding them to make them faster and more powerful that things start going wrong. But most of those who do this know the consequences. I'm in the process of building an '01 Targa with a 70cc Airsal kit, 15.15 Dellorto, foam air filter, and Tecno Estoril pipe. I don't intend to do any case matching or porting. I know it won't be that reliable or long lasting, but I'm only going to ride it in town, not on long trips. And I'm not going to put low bars on it. Peace, Jerry.