Scored piston advice. Husqvarna 61

[r1stgei]

I’m on the fence. Picked up a 61 , compression is good 150psi... looks like something got into the cylinder ...the saw was filthy. The air filter was a mess so I am assuming it was run and some crap got in there.

Rest of the saw is pretty good.. I have an extra cylinder and piston on hand but not sure whether to replace it. There is a nice scratch on the piston (photo attached). Should I replace the piston and cylinder? What do you guys think if the damage?

 

[Gord404]

Nice looking saw, looks like you need to pull that jug and hopefully it will clean up, order a new piston, meteor are good, and before you even pull it down if you can give it a vac-press test to see if an air leak caused it or after to double check your work, seals are cheap and should be replaced anyway.- good saws, worth the rebuild

 

[NSEric]

Looks like a good reason to do the 272 upgrade.

 

[lone wolf]

IF it runs good run it , if it breaks you have a spare cyl why do anything yet?

 

[Ted Jenkins]

For my use I pull the piston and cylinder to clean it up. To run it as is would possibly cause more damage. If the piston looks OK and I really do not want to replace it then knurl it a bit with some new rings. If the ring(s) is leaking the motor will generate more heat and more often will fail. Thanks

 

[lone wolf]

For my use I pull the piston and cylinder to clean it up. To run it as is would possibly cause more damage. If the piston looks OK and I really do not want to replace it then knurl it a bit with some new rings. If the ring(s) is leaking the motor will generate more heat and more often will fail. Thanks

You are a machinist? You have a piston knurling machine? They are very handy.

 

[Huskybill]

Looks like a perfect candidate for a rebuild. Maybe just the piston scored. The hard industrial chrome lining in the cylinder might be ok. Piston and rings, gaskets are cheap.

 

[r1stgei]

Looks like a good reason to do the 272 upgrade.

Is a 72 upgrade just a bolt on ? Do I need to upgrade anything else? Saw runs good. I’ll upload the video

 

[r1stgei]

Video..... runs good. Will post pics once I pop the jug off

 

[lone wolf]

Video..... runs good. Will post pics once I pop the jug off

Sounds good ,run it in wood and see what happens.

 

[NSEric]

Is a 72 upgrade just a bolt on ? Do I need to upgrade anything else? Saw runs good. I’ll upload the video

Im no expert but looked into it as I want a hopped up 61.
You need the 272 cylinder, intake and carb. You mod the airfilter holder so it fits the new carb and cut the top cover where it hits the cylinder. There's probley more, there's a how to on youtube and treads on here about it.

 

[r1stgei]

Well here is the jug off.....

 

[lone wolf]

Well here is the jug off..... View attachment 721375View attachment 721376View attachment 721377View attachment 721378View attachment 721379View attachment 721380View attachment 721381View attachment 721382

I wonder if the plating is peeled off?

 

[r1stgei]

The piston has some scratches. Only on the exhaust side. The cylinder has very very slight marks but I think I’ll keep it and change the piston. Thoughts?

 

[lone wolf]

See my other post!

 

[Huskybill]

Clean up the cylinder with two stroke oil and cross hatch it with 1500 grit paper. Don’t forget once it’s cleaned up reverse the paper and use the smooth back of it to sub the cylinder again to remove any grit that’s in the plating.

 

[lone wolf]

Am I the only one that sees a discolored area that looks like the plating is worn off? I mean if that don't clean right off then its worn through!

 

[Huskybill]

I wonder if the plating is peeled off?

I think the exhaust port is undercut from the bore size. Maybe try honing it.

 

[lone wolf]

I think the exhaust port is undercut from the bore size. Maybe try honing it.

What hones you use?

 

[cus_deluxe]

The intake side definitely doesnt look normal, but it looks the same in the transfer tunnel. either way it had serious blowby and carbon scoring