Any chance of sharing where you got the piston/ring, and how you saved the cylinder. I have a 2550 with a piston that looks like yours and it won't idle so has an air leak too, but other than that it looks great. I don't suppose you recorded your rebuild? If I get this rebuilt it will be a back-up saw or a loaner. Thanks for sharing.So I had this little 260 with a scored piston ring and cylinder. I was able to save the cylinder and replaced the piston and ring. I cannot help but modify these things alittle while I have them apart so I widened the exhaust alittle and of course the muff mod. The starter side cover had all the screws stripped out of it so I used some extra long machine screws which worked very well. When I first put it back together and started it I noticed the low side carb adjust had to be out around 2 1/2 turns, not normal to me. so I did a leak down test. I have a pressure bleeder I use for my cars and now I use it for my leak down testing and I have to say it works really well for this. Well anyways I find a leak not at the seals but when I put it back together I must not have used enough sealer on the crank case halves and found one side leaking. It was leaking 1 psi per minute, just enough to make the saw run poor. So back apart and do it right this time and saw runs great performs great. I really like these small poulans because they respond well to the mods I have been making to them. I took off the 18" bar and switched to 16". Here are a few pics.
Regards,
Lee