Originally Posted by Glowgeek

Hey folks, need some guidance on my Saito 82a. I picked up this used low hour engine and tore it down to take a look and the big end of the rod and crank pin have scoring, probably from a lean run with no castor or very little castor. I'm thinking about using some emory cloth to clean up the crank pin but I have no idea what the max clearance can be and still provide a serviceable life. The rod big end has worn through the factory red compound, whatever this is, on the top and bottom of the journal and shows minute scoring as well. Right now there is almost no discernable slop between the crank pin and rod so I'm assuming the factory clearances were very tight. I will buy a new rod but would like to salvage the crank if possible. Can I take a thousandth or two off the crank pin to clean things up?

On another note, can the valves be lightly lapped with polishing compound on this engine? I have an intake valve leak even though everything looks great, very clean. No debris on the valve stem or guide, no binding or sticking and the valve spins against the seat by hand with no discernable catches. The valve grind looks smooth under magnification but I have no way to view the valve seat in the cylinder up close. The valves will hold a cylinder full of alcohol overnight but I can hear it hiss air past the valve on the compression stroke. What do you all think?