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Can you save a scored piston?

merc_man

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The ms 260 i picked up few weeks back had a bad fuel line which must have been the cause of the lean condition. I will pressure and vac test befor i am done fixing it.
But my question is can you save a scored piston. I know scoring is not good on any piston but am wonderig can you try to litley sand it out? I can just feel the marks on rings so definatly need rings. Can also feel the sciring on piston but cant hook my finger nail on it. Pic makes it look worse than it is.

Cylinder will clean up easy enough. Can hardly feel anything in ther.
555a28383bbb3aecafa1ee66fa2fc491.jpg
d4d2cba41e8a5c06d313b7f333c0cb37.jpg
5e992695f755e49419a5876379db0dab.jpg


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1Snowcat

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I'd sand up the sides of the piston that's scuffed using 600 wet/dry cross hatch pattern on the scored side new rings and run it, make sure to NOT overheat it or run it lean you might get lucky, sometimes it works sometimes it will stick again. If you want to be sure replace it...
 

Woodslasher

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I'd sand up the sides of the piston that's scuffed using 600 wet/dry cross hatch pattern on the scored side new rings and run it, make sure to NOT overheat it or run it lean you might get lucky, sometimes it works sometimes it will stick again. If you want to be sure replace it...
I was told to never sand a piston, the grit will embed in the aluminum and wear through the plating faster. I was told is to lightly draw file the piston instead. I've done that with a lightly scuffed 045 piston and that saw still runs and pulls a 36" x .404 combo with authority.
 

huskihl

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The ms 260 i picked up few weeks back had a bad fuel line which must have been the cause of the lean condition. I will pressure and vac test befor i am done fixing it.
But my question is can you save a scored piston. I know scoring is not good on any piston but am wonderig can you try to litley sand it out? I can just feel the marks on rings so definatly need rings. Can also feel the sciring on piston but cant hook my finger nail on it. Pic makes it look worse than it is.

Cylinder will clean up easy enough. Can hardly feel anything in ther.
555a28383bbb3aecafa1ee66fa2fc491.jpg
d4d2cba41e8a5c06d313b7f333c0cb37.jpg
5e992695f755e49419a5876379db0dab.jpg


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You can do whatever you want until it’s too small for the bore. It’s just ugly. If machine marks are necessary for holding oil, it’ll just hold a little more in your low spot lol
 

Stevetheboatguy

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I have a different view on this. I work on things that when they break. You aren't walking home.

Stranded, life and death situation...... Heck yeah do a lil spit polish and let er rip.


Otherwise shell out the $40-60 for a quality replacement and know that it's not going to break the skirt off and vent the crank case for you.....

Pay once cry once if you will.


Steven
 

Stump Shot

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On this particular model there is no good reason not to replace the piston with one of the many affordable options available out there today.
If it was an antique and nothing was available to you, then it would be worth the time to clean it up and knurl and hand fit it to the bore again.
On the cylinder, it has to be cleaned up perfectly with no transfer left remaining. The ports will need to be re-beveled to remove aluminum stuck to the entry of the port which will ruin the new piston.
One thing that was told to me that I always remember is that a piston is something that is very easy to manufacture, the cylinder on the other hand is very hard to make. Which makes for a pretty easy guide.
Best of luck with your repair.
 

Al Smith

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I've been told the 026/260 came with three different mufflers and one was highly restrictive .I had a similar situation on an 024 I rescued from a dealers dead pile but the burn wasn't that bad .However were this thing mine I'd clean up the cylinder with 3M greenies and stick a Meteor in it .--plus attend to that muff so it can breathe .
 

qurotro

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Like mentioned, remove any high spot and intall new rings will work on this particular case.
But, a pair of new caber ring is $12? But the whole meteor set is only like $35.
Time is more important for me.
 

Al Smith

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Like has been mentioned I too have had good luck with Meteor but I use OEM or Wiseco circlips .I have no idea what an OEM piston would cost but Stihl for most part is very proud of their products .If rebuilt correctly and not be stingy with the mix oil ratio it might run forever .
 

merc_man

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I think i will replace the piston too. Meteor is little more than 50 with shipping. Gonna see what oem is worth too befor i order anything this saw did have pretty good compression befor i pulled it apart.
e3aa4eb4ae7d1a625f3e37865c4b0f34.jpg


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qurotro

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Have you run the saw before tear down? You can actually switch the top and bottom ring so the damaged pattern differ then it seal better. Just saying..
 

1Snowcat

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If you know the part number for the OEM piston, look on fleabay it might not be as bad as you think...
 

Pincher

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Have you run the saw before tear down? You can actually switch the top and bottom ring so the damaged pattern differ then it seal better. Just saying..

Now that's something I would do on my own stuff...
If you know the part number for the OEM piston, look on fleabay it might not be as bad as you think...
A few years back I purchased one for list price from stihl that was only $10 more than a meteor. Might be different now, if you can get them.
 

merc_man

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Oh ya it fired rite up but i could tell it was lean so i shut it off and started looking for an air leak. Thats when i seen the hole in the fuel line

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Al Smith

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That 50 Canadian would be about 39 US green bucks figuring the exchanged rate , Try Northwood saw as they list a fairly large selection of meteor .Flea bay as I type has what they call OEM but if they are or not might be questionable .
 

Duane(Pa)

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Oh ya it fired rite up but i could tell it was lean so i shut it off and started looking for an air leak. Thats when i seen the hole in the fuel line

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What size is the piston you are needing?
 

Shibby

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Its the 44.7mm cylinder.
How many cylinders were ther for the 026 and ms 260 saws anyhow?

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I'm going off memory so someone else can confirm/correct me, but I think early 026/260 had 44mm and later ones had 44.7mm cylinders. I also have a scored ms260 piston, but it doesn't look nearly as bad as yours.

Aftermarket pistons seem to be pretty good for the most part, can't say I've personally run across a bad one but I don't buy a lot. It's usually the cylinder lining/tolerances and wrist pins that are hit or miss. For rings I just buy caber considering how cheap they are and the peace of mind they give.
 

Duane(Pa)

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465884BE-9B8F-42DE-AC84-67A1242BD8EA.jpeg 4FEDD775-8547-4338-90EA-FC4F1E35A4EE.jpeg
Its the 44.7mm cylinder.
How many cylinders were ther for the 026 and ms 260 saws anyhow?

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I’m pretty sure they are either 44.0 or 44.7 ... I have an OEM 44.7 that I would give to you. The question is how to get it to Canada. CFB is trying to come to my GTG in mid May. I’m not sure what your timeline is either.D9B7EBCC-9EE1-475D-B78F-1799ACE71351.jpeg
 

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