I was given this engine recently. It is in very good condition with signs of very little running.
Three ring piston, roller bearing crank top and bottom.
The bearings are super smooth. I will replace the seals as they might be dried out a bit. Although, they feel fine. I have already cut down the excess material off the front of the crankcase.
I plan to give the bolted up crankcase to my engine rebuilder buddy to take into the workshop and mill .015 inch off the block.
Then I will check to the port timing and adjust as necessary.So far, the only guidance I have found for adjust port timing is on this thread: http://www.rcuniverse.com/forum/engi...iques-how.html
I will be following that, unless I am advised otherwise.