Jonsered Chainsaws

[Modifiedmark]

Glad you joined in on this Mark...you have much more experience with both these saws than I do. I will add that now there is an aftermarket piston for the 490 but still nothing for the 590 and that the 590 had the same exact P&C as the Husky closed port 55.....so an AM P&C for the 590 would bring back a bunch of those saws too or convert the standard 55 into a serious cutting saw.....surprised the AM hasn't figured that one out yet....would sell a bunch I bet...

Robin, I don't think the 55 CP cyl is the same as the 590 cyl. I have never had a 55 cyl to compare it to but Arrowhead has told me the 590 cyl is not the same and is actually a better piece. I have never been able to run the part numbers together either. There were a bunch of numbers to decipher also.

I would like to try one of the 44mm CP pistons, but I can't find any place to buy them but from one guy I won't buy from.

 

[Cantdog]

Robin, I don't think the 55 CP cyl is the same as the 590 cyl. I have never had a 55 cyl to compare it to but Arrowhead has told me the 590 cyl is not the same and is actually a better piece. I have never been able to run the part numbers together either. There were a bunch of numbers to decipher also.

I would like to try one of the 44mm CP pistons, but I can't find any place to buy them but from one guy I won't buy from.

Mark... I had a 590 here a couple yrs ago.....and there was this discussion on AS about the closed port 55 and the 590.....well I had a beat, broken 55 here too so I though I'd take a look.......didn't know it was closed port.....but it was ....the 55 cyl was scored to death with a bunch of fin busted off.......I compared the two......same casting numbers... same threaded holes...same in every way that I could see......didn't try to cc the combustion chamber or check port timing but to the naked eye I couldn't find squat for differences.........the 590 is gone...got traded to bama.......but I still got the beat 55 around somewhere....I'll try and get the numbers...to cheep to throw anything away.......you must have a 590 kicking around....perhaps we can revisit it and compare.....

 

[Cantdog]

Robin, I don't think the 55 CP cyl is the same as the 590 cyl. I have never had a 55 cyl to compare it to but Arrowhead has told me the 590 cyl is not the same and is actually a better piece. I have never been able to run the part numbers together either. There were a bunch of numbers to decipher also.

I would like to try one of the 44mm CP pistons, but I can't find any place to buy them but from one guy I won't buy from.

LOL.... yeah Scott is the only place I've seen them for sale.......

 

[WKEND LUMBERJAK]

Scott???????

 

[Modifiedmark]

Mark... I had a 590 here a couple yrs ago.....and there was this discussion on AS about the closed port 55 and the 590.....well I had a beat, broken 55 here too so I though I'd take a look.......didn't know it was closed port.....but it was ....the 55 cyl was scored to death with a bunch of fin busted off.......I compared the two......same casting numbers... same threaded holes...same in every way that I could see......didn't try to cc the combustion chamber or check port timing but to the naked eye I couldn't find squat for differences.........the 590 is gone...got traded to bama.......but I still got the beat 55 around somewhere....I'll try and get the numbers...to cheep to throw anything away.......you must have a 590 kicking around....perhaps we can revisit it and compare.....

Sure, I'll be up for that, and I do have a 590 here. In fact I traded Arrowhead for it. I learned long ago that I can't go strictly by casting numbers, its the finished product that may or may not be the same. I know I spent hours till my eyes went cross trying to decipher all the part numbers for these cylinders and comparing them to the Partner and Jonsereds numbers at one time.

Not a big deal really but even if the cylinders are different the pistons would probably be the same and it would be nice to have them made again.

 

[Modifiedmark]

LOL.... yeah Scott is the only place I've seen them for sale.......

I'm hearing that might change in the future.

 

[Cantdog]

Sure, I'll be up for that, and I do have a 590 here. In fact I traded Arrowhead for it. I learned long ago that I can't go strictly by casting numbers, its the finished product that may or may not be the same. I know I spent hours till my eyes went cross trying to decipher all the part numbers for these cylinders and comparing them to the Partner and Jonsereds numbers at one time.

Not a big deal really but even if the cylinders are different the pistons would probably be the same and it would be nice to have them made again.

All to true......I'll dig out that busted up 55 cyl and get some pics and numbers......

 

[WoodDean]

"and get 6-7 saws done and out the door for others including Deans 90"

Wahooooo!!!!!! . . . . . .
I'm so excited I can barely hold a thought in my head!!!

 

[Cantdog]

"and get 6-7 saws done and out the door for others including Deans 90"

Wahooooo!!!!!! . . . . . .
I'm so excited I can barely hold a thought in my head!!!

It'll be a bit yet...got the next couple weeks scheduled back to back everything!! Realistically mid to late Aug I'd guess....

 

[Cantdog]

Okay Mark, I got some pics of this beat up 55 closed port cyl.......not the best pics but the best I could do tonight....I'll recite the numbers and location in case you can't make them out in the pics. On the clutch side, down on the base it says MAHLE 44ZN15....above that between the first fin and the base it says W3....above that between the second and third fin it says A5. Over on the flywheel side between the second and third fin, on the transfer bulge it says 9R. That's all there is for numbers except the size code on the top of the cyl.....How does that compare with your 590? If remember rightly, the 590 I had here said MAHLE44ZN15 on the base as well.....don't know about the other numbers but it looked like they would swap from the Husky to the 590 or the other way around without any issues.....at least that's what I thought at the time......what do you think?

 

[tbone75]

Looks like I better keep an eye you guys , I have a few 490s to build , and a 5000 Plus that needs a case gasket , some day ? LOL
Too much stuff and not much of a body to work with . LOL

 

[SawTroll]

Okay Mark, I got some pics of this beat up 55 closed port cyl.......not the best pics but the best I could do tonight....I'll recite the numbers and location in case you can't make them out in the pics. On the clutch side, down on the base it says MAHLE 44ZN15....above that between the first fin and the base it says W3....above that between the second and third fin it says A5. Over on the flywheel side between the second and third fin, on the transfer bulge it says 9R. That's all there is for numbers except the size code on the top of the cyl.....How does that compare with your 590? If remember rightly, the 590 I had here said MAHLE44ZN15 on the base as well.....don't know about the other numbers but it looked like they would swap from the Husky to the 590 or the other way around without any issues.....at least that's what I thought at the time......what do you think?View attachment 361634 View attachment 361635 View attachment 361636 View attachment 361637 View attachment 361638

That sounds right to me, but I understand the combustion chamber is smaller in the 590 ones than the 55 CP ones. Likely the "W" numbers are different?

 

[Cantdog]

Dean.......... Had to run a couple carbs through the USC yesterday....decided to run yours at the same time while I had it going. Found the major issue...the passage between the final filter screen and the needle valve seat was nearly completely clogged...could just barely see any light through it!! That'd be the reason for the finicky carb adjustments and the flat spot off idle when you nailed it......USC took care of that.....I bet she'll purr like a kitten now. Didn't put a kit in the carb as you just did.... everything was fine except the clogged main fuel passage.....you may get your saw back sooner than later....

 

[Cantdog]

That sounds right to me, but I understand the combustion chamber is smaller in the 590 ones than the 55 CP ones. Likely the "W" numbers are different?

Yep that may well be....the 590 may carry a little more compression than the Husky cyl due to combustion chamber cc's and the port timing may be a few degrees different as well but I think the P&C will swap from the 590 to the closed port 55 saws without problems.......have to see what Mark says about his 590 cly numbers/letters......

 

[Modifiedmark]

Yep that may well be....the 590 may carry a little more compression than the Husky cyl due to combustion chamber cc's and the port timing may be a few degrees different as well but I think the P&C will swap from the 590 to the closed port 55 saws without problems.......have to see what Mark says about his 590 cly numbers/letters......

I'll try to get a look at it tomorrow if I can. Not sure I will have time to pull the jug or even if I want to do that.

I dont know if I said it in this thread or another , but the casting numbers mean very little in comparing these things.

The casting number is just that, a number for a certain raw casting, how it gets finished is the difference in the companies parts number. Look at the casting number you just posted. Most people would believe that is a 44mm bore when we in fact know a CP 55 and a 590 are both 45mm.

The 55 CP cyl also has a decomp that the 590 does not so if the casting numbers do turn out to be the same, it just proves that it means nothing.

I am pretty certain that the 51-55 Husky top ends will fit a 590 ( the 46mm OP cyls are used on the Partner 540/543 saws) but you have to use a non decomp cyl or plug it as the decomp will not fit with the 590 handle bar setup.

I would have to talk to Ed again as I forget stuff, but I'm certain he said when he compared them the 590 cyl had a smaller cc combustion chamber. I never ran a 55 CP so I dont know how they run. I am not a fan of the 55 OP saws and it seems the same OP cyls run better on the Partner saws like the 540. That could be the case with the 590 as well.

 

[RedneckChainsawRepair]

Looks like I better keep an eye you guys , I have a few 490s to build , and a 5000 Plus that needs a case gasket , some day ? LOL
Too much stuff and not much of a body to work with . LOL

I still have a nos crankcase gasket set and seals. I can be traded out of them or cabbage from the garden.

Had 590 490 5000 325 500 x 100 it seemed at times. Yes the 55 will go on the 590 or other way around.

 

[RedneckChainsawRepair]

Tbone have a 490 crankcase that needs new bearings in it too. Stripped bare to crankcase and crank left.

 

[Cantdog]

I'll try to get a look at it tomorrow if I can. Not sure I will have time to pull the jug or even if I want to do that.

I dont know if I said it in this thread or another , but the casting numbers mean very little in comparing these things.

The casting number is just that, a number for a certain raw casting, how it gets finished is the difference in the companies parts number. Look at the casting number you just posted. Most people would believe that is a 44mm bore when we in fact know a CP 55 and a 590 are both 45mm.

The 55 CP cyl also has a decomp that the 590 does not so if the casting numbers do turn out to be the same, it just proves that it means nothing.

I am pretty certain that the 51-55 Husky top ends will fit a 590 ( the 46mm OP cyls are used on the Partner 540/543 saws) but you have to use a non decomp cyl or plug it as the decomp will not fit with the 590 handle bar setup.

I would have to talk to Ed again as I forget stuff, but I'm certain he said when he compared them the 590 cyl had a smaller cc combustion chamber. I never ran a 55 CP so I dont know how they run. I am not a fan of the 55 OP saws and it seems the same OP cyls run better on the Partner saws like the 540. That could be the case with the 590 as well.

That all sounds about right....I was thinking the decomp would have to be plugged to be used on the 590. Mostly what I was getting at earlier was they were the same to the point of being able to be used on either saw and that would open up another family of saws to the aftermarket that one homogenous AM P&C set could fit....meaning more potential sales. Just surprised the AM hasn't thought of that. There are many, many OP 55s out there that a percentage of those owners would like a little more power/rpm from too, and a number of closed port 55s that are in the same predicament as the 590.....waiting for something that is NLA. I never have run a CP 55 either but from all accounts they are head and shoulders above the bigger OP 55s. I have had several OP 55s and 51s that ran well enough but were rather lackluster in performance....sold every one soon as someone needed a decent running, cheap backup saw...

 

[cwebefree]

Does anyone have pointers on a 49sp?
I'm thinking the seals are shot, drag to stall on throttle up.
Good compression.
Figuring I'm going to have to drop the points to get at the seals.
Gap?
Timing?
I must admit to have never owned a point saw, so any advice as to how to hold my mouth just right would be appreciated.

 

[SawTroll]

Yep that may well be....the 590 may carry a little more compression than the Husky cyl due to combustion chamber cc's and the port timing may be a few degrees different as well but I think the P&C will swap from the 590 to the closed port 55 saws without problems.......have to see what Mark says about his 590 cly numbers/letters......

Yes - why shouldn't it?