Compression is over 120 .mmmmm has to be something in the wireing.if valve is burned would I still have that good of compression.
The compression would feel good by hand or sound good on the electric start but it would never read good on an accurate tester.
If you have spark it cannot be a wiring issue.
I had one scoot that had the same problem. It went to three shops before the gal found me. I looked at the thing for three days before I thought of the crank key, and as soon as I put my hands on the flywheel/rotor, it spun on the crank.
Pulled the nut off, and found the key had sheared off level. I guess what happened was the nut loosened just enough for the rotor to slip. It's worth looking at.
One other thing I have done is put a socket in a 1/2" drill on a 6" x 3/8" extension and use the crank nut, and drill as an electric starter. Do this with a timing light, and the plug removed. It will spin the engine fast enough for you to read the timing marks.