Stihl 025 Repair/Rebuild/etc...

[K5krawler]

Just picked up a nice looking 025 and was happy even though it didn't run. I had done a few tests on the saw to try to get it to run, everything from fuel down the carb, new plug, removing the kill switch wire...everything. Then I said to myself this isn't going to turn out well:msp_mad:.
I pulled off the muffler and this is what I found.......

Piston (Saw front)

Piston (Saw rear)

Inside of cylinder. It doesn't look that bad but here it is.

Now can you guys recommend me a piston and cylinder either from Stihl or aftermarket that will work well for this saw? And where I could get them from? I know this is a $300 saw but with my new bar and chain that I already have for it I'd like to keep it a now used $200 saw. Thank you guys!

-K5

 

[Rookie1]

Ive never had to get a piston for one yet but would go for a Stihl one if I was keeping the saw for myself. Also I would clean the jug with acid and make sure its good before buying anything. Oh then there is the reason that happened,you need to fix that problem also. I like the 1123 series saws and have 3 of them now and wouldnt hesitate to get more.

 

[67L36Driver]

Quick search on ebay turns up a piston kit (w/pin, snap rings and rings) for $27.08. Clean up the cylinder first.

 

[K5krawler]

Bailey's - Piston Kit for Stihl 025

Piston Kit 42.5 mm for Stihl 025/MS250 MPA PC1793 Piston Kit 42 mm for Stihl 025 [MPA PC1793B] : ToolPusherSpecialtyTools.com, When You Need a Fix!

That's what I've found so far. I am going to clean up the cylinder as soon as I can get some Acid. I am thinking this saw was run too lean or without premix?

 

[Rookie1]

If it ran lean make sure you figure out why or your hard work will be for naught when it happens again.:msp_mellow:

 

[DG2244]

Check eBay.You can get a short block assembly sometimes very reasonable.That looks like a nasty straight gas job.

 

[stihl86]

It looks more like a overheat failure than lean.

 

[Fish]

It looks more like a overheat failure than lean.

Or both , or Amsoil failure, or klotz, or all 4.......

 

[K5krawler]

Or both , or Amsoil failure, or klotz, or all 4.......

Ya who knows, I'll run it off of 40:1 but till then, I am going to clean the cylinder tomorrow and see what shape it's in. Hopefully all I am is down a Piston and rings. Cheaper then a new coil!

-K5

 

[K5krawler]

Cleaned up cylinder.

Here is a few views of the cylinder. It cleaned up but I am not sure how well.

INTAKE

EXHAUST

Do you think it is okay to run? If so, I have sourced a few pistons and maybe a spare saw for $70 or so. I'd really like to just invest in a new piston and call it done.

 

[jus2fat]

The cylinder looks toasted to me!

J2F

 

[K5krawler]

Now I have my chance to upgrade to the 42.5 MM Piston/Cylinder. I assume the bolt pattern is the same for the bottom of the clam?

 

[jus2fat]

Now I have my chance to upgrade to the 42.5 MM Piston/Cylinder. I assume the bolt pattern is the same for the bottom of the clam?

Just call Bailey's AND ToolPusher Tools and find out for sure
before ya order...I wouldn't buy one off eBay!

I would try to buy one with a Meteor piston!!!

J2F

 

[sefh3]

I have an Espian piston in my 025 that I bought from Northwood Saw. I have a 3-4 tanks through it and have no problems with it. Piston, rings, clips, and pin for under $30.

 

[jus2fat]

I have an Espian piston in my 025 that I bought from Northwood Saw. I have a 3-4 tanks through it and have no problems with it. Piston, rings, clips, and pin for under $30.

Take a look at the cylinder pics...Looks toasted to me!!...
I don't see how the rings could possibly seal...??

He wants/needs a piston and cylinder combo kit.
And an upgrade to the 42.5mm size.

J2F

 

[ridgerunner97]

Chris you can hit that jug with a hone, it will run. We've done one's worse than that on both 2 stroke bikes and saws and have wound up with some real good runners. I have an 024 Super parts saw over here if you need anything, I think the jug and crank are junk on mine though. I'll look if you need anything or anything will work.

-Jon

 

[sefh3]

Can you "catch" your fingernail on the exhaust side grove? If so, I'm affraid your in need of a new cylinder. It's hard to see in the picture if the grove is "catchable".

 

[K5krawler]

Can you "catch" your fingernail on the exhaust side grove? If so, I'm affraid your in need of a new cylinder. It's hard to see in the picture if the grove is "catchable".

I can't feel anything when I run my fingernail across it. I think this is case of it looks worse than it is. Anybody have a 42mm berry brush?

 

[sefh3]

If you can't feel it I would run it. I think a new piston is cheaper than a short block for those saws. I don't think .5mm is going to make that much difference.

 

[andrethegiant70]

Chris you can hit that jug with a hone, it will run. We've done one's worse than that on both 2 stroke bikes and saws and have wound up with some real good runners. I have an 024 Super parts saw over here if you need anything, I think the jug and crank are junk on mine though. I'll look if you need anything or anything will work.

-Jon

Yes, difficult to say from pictures, but I think that cylinder needs a bunch more elbow grease before I'd call it toasted. That groove in the middle does look worrisome, but maybe that will come out also. Keep grinding on that thing 'till you get a MIRROR finish... THEN closely inspect anything that didn't come out.