Chain Sprocket Conversion

[08dirtdigger]

Bought a supposed Great Running - Quick starting Stihl MS390 off eBay to complement my MS290. When I get the thing, I realize it is much older model than my 4 yr old 290. I wanted to be able to interchange bars and chains and get a 25" for the 390.
After I get the not so quick to start thing going, I less than happy but then I realize that the bar and chains are different pitch.
Older 390 has 3/8 sprocket - newer 290 has .325.
Here is the famous dumb question pharse again.
Can I just change the chain sprocket on the older 390 so it takes the .325 8t reduced kickback bar and blades?

 

[breymeyerfam]

yes

 

[njforestfire]

Just make sure that the bar rail gauge is the same - the 039 could always be running a .058 chain drive instead of the more common .050. The .325 is .050. That is the width of the drive tooth.

 

[sugarbush]

Just make sure that the bar rail gauge is the same - the 039 could always be running a .058 chain drive instead of the more common .050. The .325 is .050. That is the width of the drive tooth.

.058 would be a strange set up for an 039.

 

[BC_Logger]

.58 is a huskey set up

 

[08dirtdigger]

Feeling And Will Be Felling Better Now

not so annoyed now about other aspects of the as advertised "Great Running - Quick Start MS390" which isn't - not including the blade and bar part. Chain rotates at idle. Fix could be just carb adjustment or maybe clutch. Wouldn't cut butter. Probably same fix. Concerns of chain brake too. Not so easy a fix. Compress OK.

Like my Stihls but expected more when I bought this 390. I could of got a '08 model with the decompression valve for $30 more if I hadn't bid so quick. Feeling stupid for not asking more questions and timing my bids better.

Oh well, You can always fix a Stihl- just take time.
Thanks

 

[Poley4]

Just make sure that the bar rail gauge is the same - the 039 could always be running a .058 chain drive instead of the more common .050. The .325 is .050. That is the width of the drive tooth.

Even if the gage of the chain is the same, the sprocket nose on the bar wouldn't be, would it?

 

[SawTroll]

Bought a supposed Great Running - Quick starting Stihl MS390 off eBay to complement my MS290. When I get the thing, I realize it is much older model than my 4 yr old 290. I wanted to be able to interchange bars and chains and get a 25" for the 390.
After I get the not so quick to start thing going, I less than happy but then I realize that the bar and chains are different pitch.
Older 390 has 3/8 sprocket - newer 290 has .325.
Here is the famous dumb question pharse again.
Can I just change the chain sprocket on the older 390 so it takes the .325 8t reduced kickback bar and blades?

They come with .325 here, so yes!

...but I am not sure that is a good move.....

 

[GASoline71]

I would change the 290 to take the 3/8". Not the other way around.

The 029/290's out here in the PNW usually come with 3/8". They handle it no problem.

Gary

 

[njforestfire]

.58 is a huskey set up

Not necessarily just a husky set-up. I've seen plenty of Stihl's with that gage.





Get rid of that .325 and go to the 3/8!!

 

[njforestfire]

.058 would be a strange set up for an 039.

Strange yes - but I'm sure someone has done it! It's something I wouldn't do.

 

[Jacob J.]

Not necessarily just a husky set-up. I've seen plenty of Stihl's with that gage.

Must be an East Coast thing. We've never sold a saw in our shop; Stihl, Husky, Jonsered, Solo, or Echo with any kind of .058" gauge chain- either .325" or .375" pitch.

I know .058" gauge is common in Canada, Lord knows why. I bought a couple of 385xpgw saws from B.C. a few years back and they both came with 32" .375"p x .058"g bars.:censored:

 

[nmurph]

08,
i would check the idle and the look at the clutch springs. they are simple to change and only cost about $6 OEM.
i would change the 290 to the .375 setup.