It looks like the muffler gasket had a piece missing. It has probably sucked dirt back in through there to cause the scoring.
Scored piston advice. Husqvarna 61
- Thread starter r1stgei
- Start date
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r1stgei
ArboristSite Operative
First off your guys are awesome. Thank you for the feedback. The piston cleaned up nice. I used 2000 grit paper. The rings on the OEM cylinder snapped as soon as I took it out ... I’m not a huge fan of the aftermarket parts i got. Muffler gasket was good... would you guys install these back with new rings? I’ll be vacuum testing the crank later today once I steal back my mityvac that my brother In law borrowed without bringing back. I’ll be taking his beer with me in the process!
Trent Curtis
ArboristSite Guru
Your on the right track- that cylinder and piston clearly aren’t going to ever be 100%. But they should work just fine for a good while.
No use in replacing piston or cylinder unless you replace both. Otherwise- clean up and run what you’ve got provided it still
Makes good compression.
While she’s apart might as well take preventative measures. Make sure you clean the ring groove as I’m sure it has some carbon build up in there. Best way to do that is to simple use the old ring.... break it in half and use it to scrape out the ring groove. Carbon build up in the groove can cause you to snag a ring later.
Also- get the carbon out of that exhaust port while you have it apart.... preventing more carbon scoring. You can do that with about anything. Sandpaper, file, dremmel and wire wheel... just make sure after you’re done to clean inside of cylinder and smooth the port on the cylinder wall. In case you left a slight lip.
Be careful reusing old piston circlips. If they were at all deformed in removal get new ones.
Then.... complete a muffler mod while you have it apart
I’ve had a few older saws that had carbon scoring, held good compression and ran for years.
As on any old, worn cylinder..... Tune the saw a but rich (healthy four stroke out of the cut)..... then make chips!
No use in replacing piston or cylinder unless you replace both. Otherwise- clean up and run what you’ve got provided it still
Makes good compression.
While she’s apart might as well take preventative measures. Make sure you clean the ring groove as I’m sure it has some carbon build up in there. Best way to do that is to simple use the old ring.... break it in half and use it to scrape out the ring groove. Carbon build up in the groove can cause you to snag a ring later.
Also- get the carbon out of that exhaust port while you have it apart.... preventing more carbon scoring. You can do that with about anything. Sandpaper, file, dremmel and wire wheel... just make sure after you’re done to clean inside of cylinder and smooth the port on the cylinder wall. In case you left a slight lip.
Be careful reusing old piston circlips. If they were at all deformed in removal get new ones.
Then.... complete a muffler mod while you have it apart
I’ve had a few older saws that had carbon scoring, held good compression and ran for years.
As on any old, worn cylinder..... Tune the saw a but rich (healthy four stroke out of the cut)..... then make chips!
r1stgei
ArboristSite Operative
Your on the right track- that cylinder and piston clearly aren’t going to ever be 100%. But they should work just fine for a good while.
No use in replacing piston or cylinder unless you replace both. Otherwise- clean up and run what you’ve got provided it still
Makes good compression.
While she’s apart might as well take preventative measures. Make sure you clean the ring groove as I’m sure it has some carbon build up in there. Best way to do that is to simple use the old ring.... break it in half and use it to scrape out the ring groove. Carbon build up in the groove can cause you to snag a ring later.
Also- get the carbon out of that exhaust port while you have it apart.... preventing more carbon scoring. You can do that with about anything. Sandpaper, file, dremmel and wire wheel... just make sure after you’re done to clean inside of cylinder and smooth the port on the cylinder wall. In case you left a slight lip.
Be careful reusing old piston circlips. If they were at all deformed in removal get new ones.
Then.... complete a muffler mod while you have it apart
I’ve had a few older saws that had carbon scoring, held good compression and ran for years.
As on any old, worn cylinder..... Tune the saw a but rich (healthy four stroke out of the cut)..... then make chips!
Perfect! Thank you very much for the advice!
Trent Curtis
ArboristSite Guru
Lastly- that cylinder will clean up a lot more using a dremmel with a split Mandral and some 150-200g emery cloth. You can even make your own split mandral using a large nail and a cut off wheel.
Trent Curtis
ArboristSite Guru
run the dremmel/ emery cloth at a nice slow-med speed. Last pass I lightly oil cylinder walls and give it one more pass.
Emery cloth is nice because it makes full/even contact with cylinder walls, and isn’t too aggressive. If you have a dremmel give it a go..... and if it cleans up nicely then order a new piston
r1stgei
ArboristSite Operative
View attachment 721508 View attachment 721509
run the dremmel/ emery cloth at a nice slow-med speed. Last pass I lightly oil cylinder walls and give it one more pass.
Emery cloth is nice because it makes full/even contact with cylinder walls, and isn’t too aggressive. If you have a dremmel give it a go..... and if it cleans up nicely then order a new piston
I will give it a try. Do you have pics of the dremel setup you used?
kyle.kipple
ArboristSite Guru
Id say carbon caused this.
If it were mine to keep I would clean up the cylinder, clean all carbon and run as is with a new ring.
If I was selling I would put your spare top end on it that you have on hand.
Sent from my iPhone using Tapatalk
If it were mine to keep I would clean up the cylinder, clean all carbon and run as is with a new ring.
If I was selling I would put your spare top end on it that you have on hand.
Sent from my iPhone using Tapatalk
