Sounds like the crank fit in the bearing is a little loose.   This is a bit strange, as usually on Ryobis they are a bit too tight.</p>

You will probably have to machine a groove in the crankshaft for a circlip to prevent the crank from "walking".  Be careful, because if it walks back far enough it is going to smack the reed valve stop and make a mess....</p>

AV8TOR</p>