After finishing off the Homelite 410 and my SIL's Stihl 020 (impulse line) I finally got back to my BP-1. Today I decided to tear it clear down in order to clean it up and replace the rings. I have taken a few saw apart, but couldn't tell you the last time I had one that was so completely covered in oily sawdust.
I was worried that maybe it had some scoring since the compression was low, but things look very good inside...except of course for the layer of sawdust in the bottom of the balance piston cylinder.
Hopefully I can spend the better part of the day tomorrow getting it all cleaned up, replacing the rings, and maybe get it put back together. I must say this is as complicated a saw as I have ever worked on with lots of intricate castings, extensive use of plastics (remember this was produced in 1962), complicated systems for the auto sharp, etc.
One day I'll start looking for a spike for this saw, I already have a few good choices for bars when the time comes.
Mark