Originally Posted by Stubbs

the engine is pretty new. only 3 or 4 tanks of fuel through it.

last time I drove it it ran fine, I burnt about 2 tanks of fuel with the girlfriend in an open field doing lots of top speed runs.

These two sentences mean bad things.....first, and engine that only has 3 or 4 tanks run through it is not broken in. Second, an engine that is not broken in should not be run at high RPM / full throttle.

Basically, you stressed the snot out of your engine with those top speed runs, and likely reduced its life considerably.

That sticking when you push the piston up is the mechanical pinch...it's supposed to be there on new engines.