Oh I'm not stuck. I have other Ryobi cranks and crankcases here to use. I am just curious if the smaller case and the crappy shrouded reed valve came on a certain model, older engines, or what.

I did check, and the larger counterweight crank won't fit in the smaller diameter case. If I ever want to use that small diameter case and reed valve for some reason, I will have to use the original crank. The problem with that is I will have to add weight to the counterweight on that crank, as it is way out of balance as it is, and the engine vibrated terribly.

If I ever really needed a crankcase and didn't want to use the unbalanced crank and shrouded reed valve, I could just chuck that small i.d. crankcase in the lathe and machine it out to the larger size. As you said, the o.d. is the same.

PE Reivers Yes, I have reviewed all your web info on Ryobis. Interesting info.

Thanks,
AV8TOR