I would run it and check it through the exhaust port instead of tearing it down. You will be able to view the rings and piston skirt without taking it all the way a part. It's less than ideal but it shouldn't cause any major problems. At least you can go cut some wood while still looking for a replacement.
I've been collecting these 82cc Macs for years and I've never found a NOS cylinder for the PM800 and newer saws. You will see used saws on eBay sometimes but they are pretty high.
That scratch will not affect compression since its below the exhaust port. All the compression will exhaust out the port before the scratch. Actually the piston won't go below the bottom of the port anyway.
Did the score come from carbon in the port or a bearing failure?
If you don't know already....
use some good sealant like Honda Bond 3 or Motoseal gray. Standard silicone red or black won't cut it.
Seal everything with the sealant you choose. Intake spacer, both sides of the boot, etc. these saws hate even minor air leaks.
Tune the saw a little on the rich side and it will live a long life. Let me know if you need some assistance.
Use 32:1 fuel/oil mix also.
For a replacement motor, you can use one from the following saws: PM800, PM805, DE80, PM8200
If you have any questions, please ask. I like to see these saws live instead of being thrown away.
Joe
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