I had my doubts about this whole lapping business. After all, it's not mentioned in the Yanmar
workshop manual. So I replaced the clutch
cone and put it all back together.
Big mistake. The transmission
works just as badly as ever. So now I'm going to take the fricken thing out again this winter, take it apart again and lap it.
I'll have to follow the link above to see how as I tried it last winter and couldn't find anything shaped like the inside of the gears to do the lapping. I wasn't about to use the new cone, which doesn't seem appropriate anyway as it surface is no where near smooth.