365 Special/Broken Pistons

[RiverLogger]

So I just got my 365 Specials (3) that I bought from Goofy Saws before he sold the lot to the ebay guy and I'm wondering if you guys can help me out. All three saws had broken pistons. All three cylinders are toast beyond use because of this and two of them have bad cranks due to the obvious introduction of "extra" metal. Is this common with the 365? Never seen such a thing. Two are broken on the top edges and one busted at the skirt. I understand the skirt break could be from lean conditions but what about the tops breaking? They're broken between the ring groove and the top. I dont have a camera that takes good detailed pictures up close.

Also the piston that broke at the skirt had scoring on the left side of the piston between the intake and exhaust ports. What does this mean? It looked perfect when I took the muffler off but not so good once I pulled the jug off.

Thanks.

 

[Big_Wood]

i've only seen it happen to one 365 out of the ton of them i have worked on. it is not a common thing at all. this piston is from a saw that some brain dead hooligan ran for many years without an air filter. pretty crazy it lasted that long. rest of the saw was good including bottom end so cylinder clean up, piston, air filter, a caber ring, and she was good to go.

 

[watsonr]

usually a break in the top is from a ring catching or gap to small

 

[RiverLogger]

But these are stock saws that I am assuming have had a little use. I just don't get it. Maybe the bottom ends were gone before the top went. I can see that but two out of three of them? Am I really that unlucky?

 

[Big_Wood]

But these are stock saws that I am assuming have had a little use. I just don't get it. Maybe the bottom ends were gone before the top went. I can see that but two out of three of them? Am I really that unlucky?

must be cause i have had far more then 3 at one time and have only seen one with a busted skirt in all the years i have been working on them. they are a very reliable saw.

 

[watsonr]

I've seen a few with bad bottoms, rod bearings are shot.

 

[Big_Wood]

I've seen a few with bad bottoms, rod bearings are shot.

i've seen many high hour ones like that as well but only one with a busted skirt.

 

[JC360]

Some ignorant gorilla using a screwdriver for a piston stop?