Well I suppose its a good thing that they're not then.. Lol. Any moped with Reed valves (or, anything with Reed valves for that matter) has them held on with 2 little screws. Directly under said reed valves is the crank, which is designed the same... On almost all 2 strokes.
Somone who only knows about the yamaha yz250 could answer my questions.
So again, I suppose it's a good thing that my questions, in fact, are not model specific.