What is the compression reading?  If you have low compression, it will never run.  Has the motor been rebuilt?  If so, did you check the ring gap?  More info and we may be able to help you better.

Rebuilt the engine last spring. Mic'd the cylinder, talked to Wayne and he sent us a new piston/rings that would give the correct clearance. Unfortunately did not write down the measurements on bore, piston, ring gap. The compression does bother me, as it is only at 60psi. We have had other engines that low that would run, but its not very impressive. Not sure what to expect from this engine, we are used to working on more "modern" bikes from the '60's-'70's.

We had the engine running with the original carb, however someone had forced the main jet in and stripped the threads and it was unable to be properly seated. It would sit there and run but no throttle control as the fuel was likely going around the main and eventually flooded the engine.

Replaced the carb with one for a later model that wayne recommended and now we can't get it to run.

Well, I'll be. Had never come across a piston cut like that before. Vertical shallow grooves cut in the skirt to aid in oil retention, but never cut clean thru the skirt. I suppose with the piston thickness and the low compression, wasn't too much danger of shattering the skirt.

Thaks for the info.