I Did A Bad Thing (Stihl 041AV)

[No1UKnow]

Without knowing any better, I used a wrench stuck in the exhaust port of my 041AV to hold the crank while removing flywheel and peened the lip of the piston, which now impinges the cylinder wall. It stops and won't go past the edge of the port. I know now why folks use rope inserted into the combustion chamber through the spark plug port for that. Wondering if I might just file or carefully grind that edge down, or do I need to remove/replace the piston? Also interested in thoughts on replacing the points / condenser with electronic ignition. Thanks!

 

[Vorhi-heesy1985]

Without knowing any better, I used a wrench stuck in the exhaust port of my 041AV to hold the crank while removing flywheel and peened the lip of the piston, which now impinges the cylinder wall. It stops and won't go past the edge of the port. I know now why folks use rope inserted into the combustion chamber through the spark plug port for that. Wondering if I might just file or carefully grind that edge down, or do I need to remove/replace the piston? Also interested in thoughts on replacing the points / condenser with electronic ignition. Thanks!

Did you manage to get the saw running again since you posted back in September? If the piston lip is lightly peened and there are no cracks in the ring land, you may be able to carefully file or grind it down without removing the entire top end. A few people have had luck doing that, though compression might take a hit depending on the extent of the damage. As for switching to electronic ignition, it's doable with an aftermarket chip but you'll want to doublecheck the flywheel taper since early 041s had a smaller one that doesn't always match newer setups. If you're still stuck, I'd pull the cylinder and inspect everything before deciding whether to replace the piston outright.

 

[tinyc0mets]

Been there! I messed up my dad's old 041AV trying to hold the crank with a screwdriver haha! Dinged the piston too. If it's just a small bump, you might smooth it out with a fine file, but if it's sticking bad, a new piston's probably safer.

I also swapped the points for a Bosch electronic module, starts way easier now. Just line up the flywheel right and double-check the coil gap.

 

[chainsaw101]

Without knowing any better, I used a wrench stuck in the exhaust port of my 041AV to hold the crank while removing flywheel and peened the lip of the piston, which now impinges the cylinder wall. It stops and won't go past the edge of the port. I know now why folks use rope inserted into the combustion chamber through the spark plug port for that. Wondering if I might just file or carefully grind that edge down, or do I need to remove/replace the piston? Also interested in thoughts on replacing the points / condenser with electronic ignition. Thanks!

yeah, been there. you need to be super careful about grinding that spot. Even a little bit of filing could leave behind metal dust, and that's the last thing you want floating around inside your crankcase.
The safest thing for a saw you want to keep running for a long time is just to bite the bullet and replace the piston. It's a pain, but you'll sleep better at night knowing it won't fail down the line