Jonsered 2172

[duramaxman05]

How many people have ran these or the 372xp? This is my father in laws saw and its 2 1/2 years old and was still running and cutting. He said it was starting to get a little weak. Now he cuts timber full time and 2 1/2yrs I think is pretty darn good. He has had several through the years and this one is actually a redmax version. I have the jonsered my self and cant say enough good about it. Considering the hours and abuse this thing has been through, I'm suprised it still runs.

 

[SpaceBus]

Looks like it found some debris. I've read a lot of good things about the 372xp, but mostly about the earlier models.

 

[duramaxman05]

Looks like it found some debris. I've read a lot of good things about the 372xp, but mostly about the earlier models.

I'm going to do some checking over on it tomorrow. I only had enough time to pull the cylinder off of it. I'm sure its ate it's fair share of saw dust and hard telling how many hours is on it. Really makes a person wander how these saws hold up like they do. 10,000 to 13,000 rpm when they are running not to mention the heat and dirt they are in.

 

[SpaceBus]

Honestly I do find modern chainsaws to be pretty amazing. They make all that power and tolerate wicked heat. The muffler design is totally flawed for a two stroke and holds all that heat right in front of the cylinder. The chewed up area on the piston is definitely why he noticed it losing power. Is there any metal missing from the cylinder? I doubt sawdust did that!

 

[duramaxman05]

Honestly I do find modern chainsaws to be pretty amazing. They make all that power and tolerate wicked heat. The muffler design is totally flawed for a two stroke and holds all that heat right in front of the cylinder. The chewed up area on the piston is definitely why he noticed it losing power. Is there any metal missing from the cylinder? I doubt sawdust did that!

The cylinder actually looks good considering the front of the piston.

 

[duramaxman05]

So I'm gonna guess the piston ring broke and then part of the piston broke off as well. That's the material smashed in to the top of the piston

 

[SpaceBus]

Could have been a victim of detonation from running too lean.

 

[duramaxman05]

Could have been a victim of detonation from running too lean.

That's possible. I just got the new top end put together and ran it. It doesn't show any signs of running lean. Has a nice 4-stroke wide open

 

[SpaceBus]

That's possible. I just got the new top end put together and ran it. It doesn't show any signs of running lean. Has a nice 4-stroke wide open

I'm not sure what else would cause the ringland or ring, to come apart like that. Could have been running it hard in the winter, got the saw hot, and then caused detonation at high RPM. Generally winter calls for a more rich mixture with the increase in air density.

 

[SpaceBus]

I also would imagine it won't have detonation issues with the greatly reduced compression from the damaged piston.

 

[salecker]

That's possible. I just got the new top end put together and ran it. It doesn't show any signs of running lean. Has a nice 4-stroke wide open

What did you use for a top end?
A new OEM piston and Jug?
Thanks

 

[PaulOinMA]

I have never dismantled a chain saw. Piston is bigger than I imagined.

 

[duramaxman05]

I'm not sure what else would cause the ringland or ring, to come apart like that. Could have been running it hard in the winter, got the saw hot, and then caused detonation at high RPM. Generally winter calls for a more rich mixture with the increase in air density.

No doubt the saw gets run hard all year long. I know he is good about adjusting and tuning his saws. He has been cutting for 30+ years. That does make since having to richen it up in the winter.

 

[duramaxman05]

What did you use for a top end?
A new OEM piston and Jug?
Thanks

I used OEM husqvarna. It's not a whole lot more than a good aftermarket set. Husqvarna uses Mahle piston and cylinders. At least on the 372xp anyways. This is actually a redmax gz7100. The 372xp, cs2172 and gz7100 made by husqvarna. Only thing different is color, plastic, and handle bars.

 

[IowaRSFBurner]

Glad you're saving it. I use its little brother, the 2165 and absolutely love it. A friend of mine got me hooked on Jonsered, his dad was a logger and used them exclusively. I had always been a stihl fan but I sure do like the way this 2165 runs and cuts wood.

 

[duramaxman05]

Glad you're saving it. I use its little brother, the 2165 and absolutely love it. A friend of mine got me hooked on Jonsered, his dad was a logger and used them exclusively. I had always been a stihl fan but I sure do like the way this 2165 runs and cuts wood.

I was always a stihl guy myself. My father in law uses dolmar and jonsered. That's how I got acquainted with them. He's had several 2166's as well. Same saw just a little less power. I like the anti vibe on the jonsered better than the stihl. I also like the jonsered straight handle bar vs the husqvarna angled. That's the only thing I dont like about my 550xp.

 

[ABMax24]

Those pictures of that piston are textbook detonation failure, likely due to poor fuel, running lean or a combination of the 2. It could also be from too far advanced ignition timing.

I'd be having a hard look at the carb and the hall effect sensor that triggers the spark.

Here's one of mine from my 800cc snowmobile engine. This was caused by a lean condition, and then a failure of the operator (me) to let out of the throttle when the detonation light came on during a hard WOT pull.

 

[salecker]

I used OEM husqvarna. It's not a whole lot more than a good aftermarket set. Husqvarna uses Mahle piston and cylinders. At least on the 372xp anyways. This is actually a redmax gz7100. The 372xp, cs2172 and gz7100 made by husqvarna. Only thing different is color, plastic, and handle bars.

Do you still have the original jug?

 

[duramaxman05]

Do you still have the original jug?

Yes I do.

 

[duramaxman05]

Those pictures of that piston are textbook detonation failure, likely due to poor fuel, running lean or a combination of the 2. It could also be from too far advanced ignition timing.

I'd be having a hard look at the carb and the hall effect sensor that triggers the spark.

Here's one of mine from my 800cc snowmobile engine. This was caused by a lean condition, and then a failure of the operator (me) to let out of the throttle when the detonation light came on during a hard WOT pull.

View attachment 270006

Thanks for the info. I am still learning on these things. Spacebus said the same thing.

 

[BIGChrisNH]

Great saw and worth saving if you can. I love my 2166.

 

[3fordasho]

Those pictures of that piston are textbook detonation failure, likely due to poor fuel, running lean or a combination of the 2. It could also be from too far advanced ignition timing.

I'd be having a hard look at the carb and the hall effect sensor that triggers the spark.

Here's one of mine from my 800cc snowmobile engine. This was caused by a lean condition, and then a failure of the operator (me) to let out of the throttle when the detonation light came on during a hard WOT pull.

View attachment 270006

My buddy and I both bought new 2172 when the local hardware store decided to close out Jonsered. Mines still great but my buddy managed to burn his up, scored piston on the exhaust side. Same store we bought from said it wasn't worth fixing so he sold it to me for parts. I told him he could fix it himself but he's not inclined to do such things. Cleaned up the cylinder (this one was worse than yours) and installed a new meteor piston. Also installed new crank seals since that's probably what caused the lean scoring on the piston. Got a 2nd good running 2172 now and learned a little about the internals of these saws.

Got $40 in the piston and maybe another $35 in seals, gaskets and assembly materials. Had to modify a socket to get the clutch off. Only thing time consuming was cleaning the saw up.

 

[Nealm66]

I’d like to find a good used 372. Didn’t know johnsereds were the same! The new saws have a different stud mount so I can’t run chisel bit until 562 which I bought and tried but just a little to big when I switch from my little one handed saw for tree work ( I’m getting old and weak) . Great saws! Now I know I can also look for the johnsered. Thanks for posting

 

[SpaceBus]

I’d like to find a good used 372. Didn’t know johnsereds were the same! The new saws have a different stud mount so I can’t run chisel bit until 562 which I bought and tried but just a little to big when I switch from my little one handed saw for tree work ( I’m getting old and weak) . Great saws! Now I know I can also look for the johnsered. Thanks for posting

Are you sure about that? I run full chisel on my Husqvarna 460 and my 395xp came with full chisel. Most folks running 372's and getting paid for it are running full chisel as well.

 

[Nealm66]

The 372 can run chisel. The new replacement size can’t. Although I’m not exactly sure weight/size would be comparison. The smallest newer model is the 562 and I probably should have tried a shorter bar on it before I got rid of it. I might end up going back to stihl 26 size. Haven’t decided