Dirtymax37

Surprising, but not at the same time. I haven't heard any much good from the 800's as a whole machine, but no first hand experience. Personally looks like that is wearing at the front or back, not on the sides. I would inspect the piston in the bore and see if it rocks much without rings on it. I would suspect possibly some wobble in the piston at TDC. Until you measure, could just be an out of round hole, worn piston skirts, etc. At TDC the piston spends alot of time, changing direction, probably which side is loaded, loading of pressure, most times with any engine the top inch of the bore has the most wear. No description of the life of this machine and age/miles/hours.