While you are at it you may as well do the bottom end too.

You mentioned 1 cylinder running cold. I didn't read the whole thread cause I'm lazy, but I have had that problem with 2 different engines.
Both times it was the crank seals failing. I checked everything else first only to find the problem deep inside.

You also have some damage to the cylinder and piston. Same as me except I discovered this at 180 kph.

I hope I'm wrong but worth checking.

Andy

Bandit_7