Jonsered 930 Project

[Drive_1305]

I found this Jonsered 930 at a junk shop and I've started on it. Its all there except some nuts and bolts and I noticed two clutch springs are missing. The bar doesn't look bad and seems to be the right one. The piston is scored pretty good on the exhaust side. The cylinder doesn't feel very bad above the port, but its fairly rough below it. The pics of the piston and cylinder aren't very good, but see what you guys think. Maybe I can save the cylinder.

 

[retoocs555]

Looks much better after the cleaning

That piston is GONE! And the cylinder looks pretty bad. If it were me I wouldn't spend any time trying to salvage it but you may get it smoothed out with some elbow grease.

If you need any parts let me know. I have some top ends that will work but I'm not sure if they are 910 920 or 930. If you're interested I can pull a couple and measure the bore. I know one has decomp.

You will end up with a good saw there

 

[Drive_1305]

I put some acid, scuff pad and 400 grit wet sand paper to it. I may have sanded through the chrome for all I know. I can still feel some small groves above the port, below feels pretty good. See what you guys think. Think it will work with a new piston?

 

[amdburner]

I have not tried this on a chromed cylinder only on sleeved bores on snowmobiles and dirt bikes. By the looks of the cylinder in your pics I would say that the cylinder would be fine as long as the plating hasn't been breached. Was the majority of "scoring" on the cylinder actually just aluminum scuffed onto the cylinder wall from the piston? The minor scoring that you are left with shouldn't be an issue.

 

[amdburner]

Can anybody tell if this cylinder is the same as a 920 cylinder? Just curious as I just picked up a 920 on ebay which runs well but should have new rings as the compression is at 130. The cylinder and piston is clean. Looking at this pic has me taking my die grinder out for a little messaging. :biggrinbounce2:

 

[SawTroll]

There are IPLs for both the 920 and 930 here - take a look.

 

[amdburner]

Thanks Troll! The numbers aren't the same partswise but the drawing looks the same. I was just wondering how much meat there was for port matching. Drives pic of the bottom of the cylinder showed there was quite a bit of difference between the cylinder and the gasket outline. I know when I decide to put new rings in I will be putting some carbide to my ports. Anybody have some specs for woods porting on a 920?

 

[SawTroll]

Dennis Greffard is my best guess, but he hasn't been active here for a while.

His username is Dennis.

 

[Drive_1305]

Im still trying to decide to use this cylinder with a new piston or get a used one. I also need to look over some other parts to see what kind of shape they're in and decide if Im going to fix it up or not. Here's a pic of the clutch. Does that look like a Jonsered clutch? It doesn't look like the one in the IPL's. It looks more like a Sthil I've seen in pics. I don't know if they make an aftermarket clutch or not- maybe a Husky or Stihl clutch and drum would fit.

Also do you think I could put a compression release in the top of the cylinder on that flat spot? One fin is broken but I don't think that would hurt anything.

Thanks!

 

[cbfarmall]

I can't think of any Stihls that use a spiral clutch spider. All the ones I've seen have straight legs. That aside, I thought all the 910/920/930s had the single spring looped around the shoes.

Chris B.

 

[amdburner]

It looks like a Husqvarna clutch to me. I think my spring is weak on my 920 so I was thinking of putting a clutch from a Husqvarna 394 on it. The broken fin on your cylinder is no big deal. The same fin on my 920 is broken. I am not sure that mounting a compression release on top of the cylinder would be a good idea. Most are ported off the side of the cylinder. I just put new rings in my 920 and haven't had a chance to start it since. The compression is unreal and I have to put my weight on it to pull it over. Starting it should prove to be really interesting!

 

[Drive_1305]

I've seen a pic of a compression release on the side of the cylinder and it looked like it was down in the cylinder far enough that the rings slide over it- maybe it wasn't. So Im curious, seems like if rings slide over the hole you would lose some compression around the ring at the hole. Unless the diameter of the hole is less than the thickness of the ring which I didn't look like it was.

Hope I made some sense there.

 

[SawTroll]

... If you need any parts let me know. I have some top ends that will work but I'm not sure if they are 910 920 or 930. If you're interested I can pull a couple and measure the bore. I know one has decomp.
....

I am pretty sure that no 920 or 930 left the factory with a decomp valve.

The model 90 did have one on the top of the cylinder, I am not sure about the 910.....

Husky 288xp has the same bore and stroke, and those made after about 1991 have a decomp valve on the side of the cylinder. I don't know if they fit the 930.....