590 jonsered

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manostihl

manostihl

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I'm planning on rebuilding my tired old 590 this winter and I was wondering where I can get a piston and possibly a cylinder as well depending on the damagei was thinking about hot rodding it a little as well are there and big bore kits or any bigger j red cylinders that will bolt on ??? Will post pics tmw
 
RedneckChainsawRepair
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If not impossible.

Just a guess, but would a 254XP piston work in a 590?

I'm thinking I was told the wrist pin on the 254 was bigger then 590 at one time. Not sure with my memory anymore though.

Yep found it in the thread where we were talking about this last year. 254 has 12mm pin and I think 590 is 10mm (not sure there again).
 
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RedneckChainsawRepair
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490590a.jpg

Copyof590piston.jpg
 
rbmopar

rbmopar

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View attachment 248606 Here's a new 590 top end I found a while ago. The lip on the cylinder that goes into the crankcase is 50mm on the 590, and 48mm on the 490/5000. To put a 590 jug on a 490/5000 you have to open up the crankcase. I don't see any problems putting a 490 jug on a 590, but have never done it.
 
Arrowhead

Arrowhead

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Between Partner 500/5000, Jred 490/590, Poulan 325 I have over 20 of these saws. (my favorite smaller saw)
The Partner 5000 closed port is the identical to the Jred 490. The 590 is better in my opinion... same compression (my running 590 has almost 200lbs) same port timing, the 590 is 45mm and the 5000+ is 44mm. Many people think a Husky 55 45mm closed port is the same as a 590. It is not, they use the same mold, but the Husky's have different timing numbers and a larger combustion chamber. They are still good, just not as hot as a true 590 top.
In my opinion the 325 Poulan/Partner 5500 is king of these style saws. At 46mm and basically the same timing numbers, they rock. :rock:

ModifiedMark is the only person I know with a 5500 Partner. :drool:
 
manostihl

manostihl

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i think id like to do some serious portwork to the 590 if i can get a piston :cool2:i guess ill jus have to tear her down when i got the money and see what i got to work with
 
Arrowhead

Arrowhead

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is this the open and closed port piston ???? whats the difference

Both are closed port. The 5000 on the left uses a full circle piston skirt. The 590 on the right uses the more traditional style piston.
All 590's are closed port. Open port is a solid piston and the transfers are completely open on the cylinder. In the pic, the 590 jug appears to be an open port on that angle, but they are closed. They came with the skirt cut back from the factory.... at least most of them. One of my 590's has a completely skirted jug like the 490/5000.
 

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