I would pull the plugs and get a compression check.
Hard starting when warm is sometimes a result of low compression.
When tying to start, does it ever want to slow way down or "jump backwards"?
Uncle "Richard" Douglas has a Land Rover with big wheels that never gets stuck... until he breaks something so it won't go. Uncle Douglas always breaks something. - Anna Crowther at the Conclave 2012 (AKA Carburetor Neck)
"What's with this death wobble, Uncle Douglas, I can't keep it in 1 lane?"
UD: "Just Power through it man!"