Stihl 021 to 025 conversion

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NC Hillbilly

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Feb 23, 2011
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Location
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I have an 021 with the non adjustable "H" jet and am thinking of replacing the jug / piston with one for an 025. I know I will have to replace the carb and crank seals , as far as I can tell everything else will work. If anyone can think of something else I will need to change, please speak up. I assume it will be as simple as tearing everything apart and swapping the pistons / jugs replacing the seals and carb swap am I right? This saw was given to me as a non runninng freebie and is in really good shape, runs well but I am a tinkerer and it would give me something to do on my days off. I would also be gaining about 1hp as far as I can tell:msp_smile:.
 
I have a few extra adjustable carbs for a MS 250 if you need one but I would put a carb kit in it
 
I have just noticed after looking at the ipl for the 025 that it has a heat sheild and uses a gasket also. Would I need these items also?
 
Just get the whole engine off freebay

I've pick up several from there for under $35
 
Guess I looked at the stihl shop manual wrong, I thought it was a 32mm stroke. No worries I'll just leave it alone and pick another to play with. Thanks anyway
 
Guess I looked at the stihl shop manual wrong, I thought it was a 32mm stroke. No worries I'll just leave it alone and pick another to play with. Thanks anyway

Pick up a cheap crank off Ebay, and throw an 025 cylinder and piston on it. You'll love it. Make sure you have the fully adjustable carb (at the offer above I'd jump on it!). Otherwise the stroke and the cranks are different on these saws (021 vs 025). Stihl also made a change in the pistons -- by half a millimeter for the later 025's (if I'm not mistaken). If you're on the skinny side the half mm will drive you crazy. The saw will go together, and slightly crank, but NEVER run. (don't ask me how I know).
 
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Hillbilly, you are right, you have a case of CAD. However, you would not regret the 025 swap. It will bring more life to that particular model saw. How far northwest are you in NC?
 
Hillbilly, you are right, you have a case of CAD. However, you would not regret the 025 swap. It will bring more life to that particular model saw. How far northwest are you in NC?

I have CAD bad!!! I will do the swap but it will have to wait a little while :msp_rolleyes:. I am up in Lansing 3.5 miles as the crow flys to Whitetop Va.
 
I've been out in my barn doing some stuff to a 026 and found 4 adjustable carbs for the MS 250 :msp_wink:

Also two carbs for 026

Two 044 carbs

One 440 carb

Last but not least one 660 carb


JMO
 
howdy hillbilly.i aint too far from ya.i live down butler way next to the lake.came to a cookout up bear tree last year and drove through white top to look around.
 
howdy hillbilly.i aint too far from ya.i live down butler way next to the lake.came to a cookout up bear tree last year and drove through white top to look around.

Howdy back! I use to be down your way alot when I dated a girl that lived in Doe 20 some odd years ago.
 
I have CAD bad!!! I will do the swap but it will have to wait a little while :msp_rolleyes:. I am up in Lansing 3.5 miles as the crow flys to Whitetop Va.

Yep, been there. I love it up there around Ashe county. Many friends in that area. I head up to the N. Wilkesboro Flea Mkt occasionally.
That's some beautiful country up that way and lots of friends as well. Bet its purdy up there today!
 
Yep, been there. I love it up there around Ashe county. Many friends in that area. I head up to the N. Wilkesboro Flea Mkt occasionally.
That's some beautiful country up that way and lots of friends as well. Bet its purdy up there today!

Ever find any deals there? I have never been but plan on going sometime soon.
 
OP check with your local saw shop; saw shops in my area have sales atleast once a year for saws that were fixed and never pick up or saws that the owner of the saw didnt want fixed and never picked up :msp_wink:


JMO
 
OP check with your local saw shop; saw shops in my area have sales atleast once a year for saws that were fixed and never pick up or saws that the owner of the saw didnt want fixed and never picked up :msp_wink:


JMO

I am going to visit a few tomorrow to see what the have :msp_scared: I will just have to say No! No! No!;)
 
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