Jonsered 490 Advice

[MotoMax]

pull the cylinder, that takes some minutes on this saws, and take pictures, then we will see :msp_smile:
I rescued 4 partner 5000/jonsered 490 cylinders with scored pistons, and one of the pistons will likely also be used again. I slightly grinded it with emery cloth.
If the piston is not saveable, you can use a Husqvarna 246 piston, but you have to work that. I did that on one of my 5000, the saw runs really great.

regarding the cylinders used on this saws:
Open Port:
Partner 500 44mm
Partner 5000 (early) , 44mm
Partner 500 Formula ,45mm
Partner 540 46 mm
Poulan 325 (late, at least it's said) 46mm
I know somebody who has an open port Jonsered 490, and he saiys it's original. Mine 1983 is closed port.

closed port
Partner
5000 (later), 5000 Plus (always), Jonsered 490 (more or less always), all 44mm.
Jonsered 590, 45 mm
Partner 5500, 46mm and early Poulan Pro 325.

Then there where also domed (slightly) and flat top pistons in 5000 Plus. One of my 5000 Plus has a domed piston, the 5000 (late model, closed port) does not and the other 5000 also (by the way, this is a GDR model, exported to eastern germany).
Max

 

[Chainsaw Mark]

pull the cylinder, that takes some minutes on this saws, and take pictures, then we will see :msp_smile:
I rescued 4 partner 5000/jonsered 490 cylinders with scored pistons, and one of the pistons will likely also be used again. I slightly grinded it with emery cloth.
If the piston is not saveable, you can use a Husqvarna 246 piston, but you have to work that. I did that on one of my 5000, the saw runs really great.

regarding the cylinders used on this saws:
Open Port:
Partner 500 44mm
Partner 5000 (early) , 44mm
Partner 500 Formula ,45mm
Partner 540 46 mm
Poulan 325 (late, at least it's said) 46mm
I know somebody who has an open port Jonsered 490, and he saiys it's original. Mine 1983 is closed port.

closed port
Partner
5000 (later), 5000 Plus (always), Jonsered 490 (more or less always), all 44mm.
Jonsered 590, 45 mm
Partner 5500, 46mm and early Poulan Pro 325.

Then there where also domed (slightly) and flat top pistons in 5000 Plus. One of my 5000 Plus has a domed piston, the 5000 (late model, closed port) does not and the other 5000 also (by the way, this is a GDR model, exported to eastern germany).
Max

Hi MotoMax,

Thanks for the great information on the cylinder piston specs. Great information. When I get time to tear it apart I will take pictures and post them. I am a snowmobile nut and have a couple of problem snowmobiles to fix first. But this post has given me hope that the 490 can be resurrected.


Mark

 

[pioneerguy600]

Well Niko, looks like you need a reminder. :msp_tongue:

She's a pretty shade of yellow if you ask me.

They are a pretty saw,..very nice one you have there, Mark. I recently came to own a couple of them, got to clean them up and see what I got.