Tell my somewhat worn out engines that the piston's supposed to expand more than the cylinder, and stay that way for a hot restart.... I've got a few that will run OK (for trainers and such) but won't hot re-start at all due to lost compression from the cylinder expanding more than the piston. (feels like 0 compression when hot. Already marginal when cold I'll admit.)

And... ABC engines by design have the upper cylinder expand faster than the piston. freeing up the piston as they get warmer. That's why the new engine is VERY tight at TDC, and loosens up, becomming quite easy to turn immediately after its been run.

Motorcycles don't use ABC construction. Totally different metalurgy involved.