Jonsered Chainsaws

[Bob Hedgecutter]

It was thin paper. When I measured the thickness the difference was small, in the range of 0.05 mm.

Cut an oversized square out of a paper grocery bag, cut a hole in the middle for the rod to poke through, ink the case cylinder mounting surface, do an ink transfer onto the paper, cut out your new gasket with a razor or similar. Hollow punches can be handy to make the holes- but not a must have.

 

[ErnieG]

Working on a 2171 ...full disassembly for a rebuild and I noticed some mag rot in the case ...what's everyone's thoughts?
Thanks
Ernie

 

[Real1shepherd]

Working on a 2171 ...full disassembly for a rebuild and I noticed some mag rot in the case ...what's everyone's thoughts?
Thanks
Ernie

Weird.....everything else in there looks so clean. I wonder if that's from ethanol being in there for an extended period of time?

I'd get in there and scrape it down to good mag and reevaluate. It 'looks' surface, but you've gotta get all that bubbling out of there. Honestly, I'd split the case and go after it. If not, use a Dremel/Forstner with different bits to eat away the rotting mag and then re-polish it. If the rot goes really deep, I'd consider the cases toast.

Kevin

 

[ErnieG]

Weird.....everything else in there looks so clean. I wonder if that's from ethanol being in there for an extended period of time?

I'd get in there and scrape it down to good mag and reevaluate. It 'looks' surface, but you've gotta get all that bubbling out of there. Honestly, I'd split the case and go after it. If not, use a Dremel/Forstner with different bits to eat away the rotting mag and then re-polish it. If the rot goes really deep, I'd consider the cases toast.

Kevin

Hopefully it's not to deep ..it looks more surface but not completely sure till I get the case split and get it cleaned up .
Would you recommend a repaint just inside the case where the rot is ..and what paint would I use ?

Thanks
Ernie

 

[numnutz6383]

@Cantdog, @Real1shepherd or anyone else that may have the info, what's the torque spec for the head bolts on a Jonsered?

 

[Real1shepherd]

@Cantdog, @Real1shepherd or anyone else that may have the info, what's the torque spec for the head bolts on a Jonsered?

12-13Nm......which is like 8.9-9.6 ft/lbs. That's for the Husky 2100.....Jonsered should be similar. I've always done it by 'feel' with a long T-handle Allen.

By comparison, the spark plug is supposed to be 20Nm....technically. You gotta think of the diameter size of those bolts and that they're going into soft mag.

Kevin

 

[Real1shepherd]

Hopefully it's not to deep ..it looks more surface but not completely sure till I get the case split and get it cleaned up .
Would you recommend a repaint just inside the case where the rot is ..and what paint would I use ?

Thanks
Ernie

You don't really need to repaint, but for the inside, I'd use high-heat engine paint. But to get it to stick you'll have to heat it with a propane torch, clean the surface and repeat three or four times. You're heat cycling the mag to ooze all the oil out.

In the pics, some of the blisterings looks pretty intense.....hope not!

Kevin

 

[numnutz6383]

12-13Nm......which is like 8.9-9.6 ft/lbs. That's for the Husky 2100.....Jonsered should be similar. I've always done it by 'feel' with a long T-handle Allen.

By comparison, the spark plug is supposed to be 20Nm....technically. You gotta think of the diameter size of those bolts and that they're going into soft mag.

Kevin

I don't trust myself not to over-tighten the bolts, I have a tendency to hamfist things.

I have the saw about 90% put together, all I have left is to fix the heated handle switch, 2nd coat of Redkote, mount the flywheel and run the fuel line.

 

[numnutz6383]

So I got the piston and cylinder mounted the other day. During the installation I tried using the brand new wrist pin (came with the P&C kit) and a brand new OEM bearing I was able to locate, and the wrist pin was REALLY tight going in, couldn't get it installed

Got me thinking, how tight is too tight? How loose is too lose?

Ironhorse over on YT had a video in which he talks about using valve grinding compound to lap a new wrist pin in these situations. I wasn't sure how good of an idea that is so used the old wrist pin and bearing. I have to take the cylinder off anyway (I realized I didn't make sure the circlips were at 12/6 O'clock positions). Should I try lapping the new wrist pin and installing it and the new bearing?

 

[Real1shepherd]

So I got the piston and cylinder mounted the other day. During the installation I tried using the brand new wrist pin (came with the P&C kit) and a brand new OEM bearing I was able to locate, and the wrist pin was REALLY tight going in, couldn't get it installed

Got me thinking, how tight is too tight? How loose is too lose?

Ironhorse over on YT had a video in which he talks about using valve grinding compound to lap a new wrist pin in these situations. I wasn't sure how good of an idea that is so used the old wrist pin and bearing. I have to take the cylinder off anyway (I realized I didn't make sure the circlips where at 12/6 O'clock positions). Should I try lapping the new wrist pin and installing it and the new bearing?

Ironhorse is the last person on Earth you need to get advice from....you'd be better off getting advice from guys shooting craps on a street corner.....'nough said. It's OK to drift in a wrist pin as long as it doesn't get scored. Use mix oil or prelube. Drift it in and then back out......check for scoring. If you did have to lap it at that point, do it on a stout piece of plate glass.

If the old wrist pin has no appreciable wear across its length, I'd use that and the old bearing....they're worn in together. Yrs ago, I put back my used wrist pin on a Hsuky 2100. Hated to, but nothing was available new. And it did have some wear where it rode in the bearing. I've poured the coals to it many times since then...no issues or noise from a loose wrist pin.

Kevin

 

[numnutz6383]

Ironhorse is the last person on Earth you need to get advice from....you'd be better off getting advice from guys shooting craps on a street corner.....'nough said. It's OK to drift in a wrist pin as long as it doesn't get scored. Use mix oil or prelube. Drift it in and then back out......check for scoring. If you did have to lap it at that point, do it on a stout piece of plate glass.

If the old wrist pin has no appreciable wear across its length, I'd use that and the old bearing....they're worn in together. Yrs ago, I put back my used wrist pin on a Hsuky 2100. Hated to, but nothing was available new. And it did have some wear where it rode in the bearing. I've poured the coals to it many times since then...no issues or noise from a loose wrist pin.

Kevin

So once the pin is placed in the bearing and in the connecting small end, what's "too tight"? Should they spin fairly freely? Or, if tight they will wear-in/break-in eventually?

 

[Real1shepherd]

So once the pin is placed in the bearing and in the connecting small end, what's "too tight"? Should they spin fairly freely? Or, if tight they will wear-in/break-in eventually?

So once it's put together if it's anything but smooooooth(like it catches a bit), when you rock the piston back and forth on the conrod.....I'd say it's too tight. Could it break in(?), sure....but I don't that that is the best shop practice.

Kevin

 

[numnutz6383]

So once it's put together if it's anything but smooooooth(like it catches a bit), when you rock the piston back and forth on the conrod.....I'd say it's too tight. Could it break in(?), sure....but I don't that that is the best shop practice.

Kevin

Got ya.

Is this a common occurrence to happen? An OEM wrist pin + OEM bearing being too tight in an OEM piston/connecting rod?

 

[Real1shepherd]

Got ya.

Is this a common occurrence to happen? An OEM wrist pin + OEM bearing being too tight in an OEM piston/connecting rod?

I've never seen it before in OE stuff....it would have been a real fluke. But.....with so much stuff now aftermarket or claiming to be OEM it could be a 'thing'.

Kevin

 

[Cantdog]

So I got the piston and cylinder mounted the other day. During the installation I tried using the brand new wrist pin (came with the P&C kit) and a brand new OEM bearing I was able to locate, and the wrist pin was REALLY tight going in, couldn't get it installed

Got me thinking, how tight is too tight? How loose is too lose?

Ironhorse over on YT had a video in which he talks about using valve grinding compound to lap a new wrist pin in these situations. I wasn't sure how good of an idea that is so used the old wrist pin and bearing. I have to take the cylinder off anyway (I realized I didn't make sure the circlips were at 12/6 O'clock positions). Should I try lapping the new wrist pin and installing it and the new bearing?

What is to tight? The wristpin in the piston or the wristpin in the roller bearing?

 

[Bob Hedgecutter]

What is to tight? The wristpin in the piston or the wristpin in the roller bearing?

Having not read back- if it is piston to pin, is it an aftermarket piston and OEM pin?

 

[Real1shepherd]

I took it to mean the pin and bearing might be too tight together. If the pin can be pressed into the piston(clamp and right-sized sockets work well), but the bearing/pin rotates freely, he's good.

Now if the pin is too tight going into the piston like in cracking it.....no. I am confused now that you brought it up, as to what's aftermarket and what's OE?

Kevin

 

[numnutz6383]

All of it's OEM, at least it was advertised as such when I purchased them. The piston, cylinder, wrist pin and circlips came as a kit and I'm almost certain are OEM. The bearing was advertised as an OEM Husqvarna part (I think I got it on chainsawr.com).

The wrist pin was too tight going into the piston. The bearing rode freely on the wrist pin, but once inserted into the small end of the rod, it was tight.

 

[Cantdog]

All of it's OEM, at least it was advertised as such when I purchased them. The piston, cylinder, wrist pin and circlips came as a kit and I'm almost certain are OEM. The bearing was advertised as an OEM Husqvarna part (I think I got it on chainsawr.com).

The wrist pin was too tight going into the piston. The bearing rode freely on the wrist pin, but once inserted into the small end of the rod, it was tight.

I am confused…. You say the wrist pin is too tight in the piston…. Then you say the bearing is too tight on the wrist pin once assembled. Being tight in the piston bosses is ok…… wrist pin does not need to move. Did you force the wrist pin through the bearing? This can deform the bearing cage. On assemblies that don’t just slide together, I usually insert the old wristpin in from the other side to align the bearing and off side piston boss then slide the néw wrist pin in the other boss forcing the old one out. This keeps everything lined up.

 

[numnutz6383]

I am confused…. You say the wrist pin is too tight in the piston…. Then you say the bearing is too tight on the wrist pin once assembled. Being tight in the piston bosses is ok…… wrist pin does not need to move. Did you force the wrist pin through the bearing? This can deform the bearing cage. On assemblies that don’t just slide together, I usually insert the old wristpin in from the other side to align the bearing and off side piston boss then slide the néw wrist pin in the other boss forcing the old one out. This keeps everything lined up.

I was probably unclear in my explanation. When I was installing the new wrist pin, it felt much tighter going through the piston boss when I compared it to the old one, but I figured it's a press fit so that may be fine. Then I put their respective bearings into the small end of the rod (without the wrist pin in the piston) then put the wrist pin through just to see how they fit in just the rod (first picture). The old one felt subjectively a better fit.


So then I too my calipers and measured across the bearing with the wrist pin installed.
Old wrist pin+bearing was 12.75 mm. New pink bearing was 12.87 mm.


There is a slight difference in the design of the new bearing vs the old one, old one on the right and new one on the left. The old one's cage is recessed a small amount from the edges, where the new one is one same diameter edge to edge.