Hey Centerline...

Yeah, old Macs are tough to find parts for. I run (just for fun, and only occasionally cuz it's so loud!) an old 710 Auto...it's pure testosterone. But onto your problem....make sure your bar nut tightening technique is correct: you are lifting up on the bar nose while tightening, right? (This puts the bar/chain in it's "cutting" orientation. You'll notice that if you let the bar hang down prior to tightening the bar nuts, the chain will be looser; when you cut -- assuming you're cutting with the bottom of the bar -- you force the bar up, tightening the chain.) Unless the sprocket is terribly gutted, chain climb should not be the problem. As you say, it's oiling, so excessive heat shouldn't be the problem. How is the tensioning screw assembly? Does it fit properly in the bar tensioning hole? Is there a lot of slop there? Often times I see people torquing the bar nuts to 5 million foot-pounds trying the keep the bar from moving and ignoring the real problem. It usually doesn't work, and tends to make things worse.

If you're the type, keep an eye in eBay for the saw; if it's there you can occasionally pick up a carcass for parts for very cheap. It's not there now, I looked...

Anyway, call Baileys at (800) 322 4539 and ask them about parts. They probably won't have them, but they should be able to refer you to someone who does, Oh, Baileys is a big logging outfit in California...nice folks, cheap prices, knowledgeable. Website at baileys-online.com. (I don't work for them!)

Cut safe!

Fid