I got this 110 with the top end off it, but it came with a new cylinder and piston/rings. Put it back together after lapping the valves. Put it back in the frame and installed new wiring harness. Tried to start it, but it just keeps turning over, never even close to starting. I've tried starter fluid, carb cleaner and straight gas. It has plenty of spark. I've changed the plug out with different ones. Have swapped all electrical parts, but still nothing. I've pulled the kill wire from cdi. Still nothing. Compression test shows 180psi. I've never had a motor with psi that high. I've tried everything thing I can think of. Any other suggestions?

 

Forgot to mention that timing was right on and I checked the valves and they were right where I set them.

 

You wrote that you have checked timing, but have you checked both valve timing and ignition against true TDC by piston? Engines need just the right amount of fuel to fire, probable cause is carburettor, give it a good clean out. Then, for particularly recalcitrant engines I go for no choke but a sniff of butane gas from a gas blowlamp. This has the advantage that too much will just evaporate, not wet the plug.

 

I checked the valves at tdc and they were right on. I don't even have a carburetor on it yet, I was putting fuel down the intake.