Jon1270
Minister of Fire
That really doesn't look bad at all. The crosshatching from the cylinder's factory honing is still very obvious so I'd say the cylinder was in great shape before this little misadventure. I don't see any scoring, just a fairly small amount of aluminum transfer which would've been easy to clean up. That bore plating is very hard, so I doubt you did any damage with handheld emery cloth. Also, damage below the exhaust port (where most of the transfer seems to have been) wouldn't affect compression. I think it's going to be fine.
Some little tips that might help:
Buy new OEM clips for the wrist pin. They're better than even the Meteor clips, and are cheap. Don't try to reuse the originals, even if they seem to be okay. Buy three, in case you spoil or lose one.
While you're at it, buy a new base gasket.
ereplacementparts is likely to be a good source for both clips and gasket.
Rinse the heck out of that cylinder, to be sure you've eliminated any grit remaining from the emery cloth. It's not ferrous, it won't rust. Careful with harsh detergents, though; a brief spritz with simple green as a degreaser won't hurt it, but don't let anything like that remain on the surface for long.
Muster an extra measure of finesse when installing the ring onto the piston. It's easy to slip and scratch the piston surface.
There will be a little arrow stamped on top of the piston. It should point towards the exhaust.
The openings on the retaining clips should point either straight up or straight down, i.e. in line with the stroke of the piston. If it is perpendicular to the stroke of the piston then there's a chance that its own inertia could cause it to flex and pop loose at high RPM's, which would likely lead to catastrophic failure.
Some people put the saw inside of a big clear plastic bag and reach inside of that to install the clips. If a clip pops out of place and goes flying, the bag saves you from hunting around the room trying to find it.
A simple piston ring compressor(broken link removed to http://www.ebay.com/itm/STIHL-RING-COMPRESSER-026-031-032-036-038-041-045-056-044-046-064-066-084-088-/351118895811?pt=LH_DefaultDomain_0&hash=item51c0512ac3)would make reassembly easier, but is not absolutely necessary. Also, see the (broken link removed to http://www.ebay.com/itm/New-502507001-Piston-Stop-Ring-Compressor-Stihl-Husqvarna-Homelite-Tool-Kit-/130617654291?pt=LH_DefaultDomain_0&hash=item1e696b3c13) at the bottom of the main pic on this listing? That spans the crankcase opening (slot is for the connecting rod) and supports the piston while you negotiate the bottom of the cylinder over the ring. You can make an equivalent tool by simply cutting a slot in a piece of scrap wood.
Tightening torque for the cylinder is 8 to 10 Nm, or 70-88 inch pounds. You probably don't have a tiny torque wrench, but keep in mind that those little cylinder bolts should be quite tight, and tightened evenly. After you think you've got them all tightened down, go around and snug them all up again.
Let us know how it all goes! I think you and the saw are going to be just fine.
Some little tips that might help:
Buy new OEM clips for the wrist pin. They're better than even the Meteor clips, and are cheap. Don't try to reuse the originals, even if they seem to be okay. Buy three, in case you spoil or lose one.
While you're at it, buy a new base gasket.
ereplacementparts is likely to be a good source for both clips and gasket.
Rinse the heck out of that cylinder, to be sure you've eliminated any grit remaining from the emery cloth. It's not ferrous, it won't rust. Careful with harsh detergents, though; a brief spritz with simple green as a degreaser won't hurt it, but don't let anything like that remain on the surface for long.
Muster an extra measure of finesse when installing the ring onto the piston. It's easy to slip and scratch the piston surface.
There will be a little arrow stamped on top of the piston. It should point towards the exhaust.
The openings on the retaining clips should point either straight up or straight down, i.e. in line with the stroke of the piston. If it is perpendicular to the stroke of the piston then there's a chance that its own inertia could cause it to flex and pop loose at high RPM's, which would likely lead to catastrophic failure.
Some people put the saw inside of a big clear plastic bag and reach inside of that to install the clips. If a clip pops out of place and goes flying, the bag saves you from hunting around the room trying to find it.
A simple piston ring compressor(broken link removed to http://www.ebay.com/itm/STIHL-RING-COMPRESSER-026-031-032-036-038-041-045-056-044-046-064-066-084-088-/351118895811?pt=LH_DefaultDomain_0&hash=item51c0512ac3)would make reassembly easier, but is not absolutely necessary. Also, see the (broken link removed to http://www.ebay.com/itm/New-502507001-Piston-Stop-Ring-Compressor-Stihl-Husqvarna-Homelite-Tool-Kit-/130617654291?pt=LH_DefaultDomain_0&hash=item1e696b3c13) at the bottom of the main pic on this listing? That spans the crankcase opening (slot is for the connecting rod) and supports the piston while you negotiate the bottom of the cylinder over the ring. You can make an equivalent tool by simply cutting a slot in a piece of scrap wood.
Tightening torque for the cylinder is 8 to 10 Nm, or 70-88 inch pounds. You probably don't have a tiny torque wrench, but keep in mind that those little cylinder bolts should be quite tight, and tightened evenly. After you think you've got them all tightened down, go around and snug them all up again.
Let us know how it all goes! I think you and the saw are going to be just fine.
. I was able to lightly sand the cylinder with emery cloth to remove the scoring just underneath the down stroke on the muffler side. I installed a Meteor piston and ring (42mm). I also installed a new partition wall intake. The most difficult part was putting the carburetor back on the saw....I don't cuss but I came close 
. Thanks all for your help! Hopefully I won't make the stupid mistake of not checking my gas and oil mixture ever again!
