its been a busy day, but I got the MB290 engine tore town pretty much. I got a few photos of the innards for you guys to lay a eyeball on! I found the front bearing to be super loose. The piston and rings look good to me. The bottom of the sleeve has a strange condition now. There was no gasket on cyl base...just sealant. I think with no gasket there is better compression, but the bottom of the sleeve is then closer to fly-weights. That clearance was not enough with loose bearings allowing the bottom of the sleeve to be hit by the counter balance. It curled up a .030+ edge on bottom edge of sleeve. I think grinding a little off that edge will be a good idea. Also it sure needs new bearings. Bearings are not that expensive. I will fix it. I will also check balance the best I can and make sure crank is strait. Capt,n