79cc predator should be 5/8" pto shaft. If you're having clutch & rear sprocket alignment issues, and feel you need to space the clutch outward more, you can buy "machine bushings" at your local hardware store. That's what I remember them being labeled as in the little pull out bins at Ace Hardware here in Phx, AZ. Machine bushings (iirc) will have a very close I.D., and they come in different thickness's(es?) .0180, 0.036?
A predator 79cc on a Western Flyer...??? We've all seen engine plates that have been "butchered" to mount different motors than would have been originally installed!!! (not that you're going to do that) But maybe you could offset the rear wheel a little with some different size spacers; ie, 4" angle grinder and a file. That is, if, that's your problem... It's best to let the clutch float a little back and forth on the shaft if you have every thing lined up pretty close. Just trying to help!!! :thumbsup: