Disston, I agree the left cylinder is marginal but the obsessive/compulsive part of me would drive me nuts if I didn't address it. I hadn't planned to do an engine rebuild for a couple of years but here I am being sucked into a black hole. Going to a set of bigger cylinders also means the Bing 26mm carbs will have to be replaced - where will it end? Probably better to rebore. . .
JonnyCash - I did the fingernail test and you're right, slight roughness at the center of the lifter. Now I see what Disston means about pitting. Very subtle.
Today's task was to remove the crank outer bearing and sprocket. Bearing pops off with little difficulty -
The manual makes it sound like pulling the sprocket is a piece of cake - don't believe it. A little heat helped but it was still reluctant to release. The manual is definitely right, however, about protecting the crank end with pennies -
This explains why there was a lot of chain slop -