Well... This sucks!

[cgraham1]

Bought this very nice Jonsered a few months ago. It had a lot of compression and ran very strong. I found out after I bought it that it had a big bore kit. I'd rather have OEM, but whatever, it ran good and I was happy with it. I've only ran it a few times.
So, I took it out the other day and fired it up, made a couple cuts, and it died. Yesterday, I put the compression tester on it, 135 psi.

I knew something was up, because the rope was much easier to pull than before, but my research said 135-140 was okay on a 372/2171.

Well, I decided to pull the jug and the first thing I find is the damn cylinder bolts are loose. I mean way loose! Like falling out, all 4 of them.
This is what I found...


I guess from now on I'll be checking the cylinder bolts whenever I get a new saw!

 

[fearofpavement]

Yep, that sucks in a bad way. Sorry.

 

[jus2fat]

I don't want to come off as a wiseguy...but as soon as you found out it had a different cylinder on it...

you should have pulled the cylinder and checked everything out...you would have found this problem then.

Looks like the cylinder will clean up OK..add a new piston and hopefully you're back in action...

J2F

 

[cgraham1]

I'm still learning. I can buy a new piston and rings for $40, so it's not the end of the world! I should've checked it out a little better, I'm not trying to blame anyone else.

 

[Chris-PA]

That's a bummer. I always Loctite them.

 

[jus2fat]

I'm still learning. I can buy a new piston and rings for $40, so it's not the end of the world! I should've checked it out a little better, I'm not trying to blame anyone else.

I knew you weren't...I read your posts and I think you are a very good member..!! - you just got screwed on this deal..

I will only buy a used chainsaw from one stihl dealer way up in Michigan..he checks everything out before he sells and stands behind the sale.
( my 192T and 200T and 036 all came from him...this Ebay and Craigslist offerings just aren't my "cup of tea"..!! )

J2F

 

[blsnelling]

I've never used loctite on cylinder bolts, and I've never had one back out.

Put a new piston in it, and you still have a AM topend. Did you contact the seller about this? That should have been disclosed.

 

[cgraham1]

It was a private party deal, so I don't think I can do anything about it. And, Unfortunately I can't spend $300 on a new OEM top end at this time. I guess I learned a hard lesson on this one!

 

[Matt B]

They were loose on my 064. The seller told me it was a dusty old saw he'd forgotten about and had an 066 cylinder on it. Got it for a v good price so took the risk after checking comp and P&C.

Turned out to have an OEM 064 cylinder held down with 2 tightish bolts, the 3rd was loose and the 4th stripped. Luckly didn't run it, was v tempted tho'.

Didn't trust anything the guy told me after that so the saw was torn down and properly fixed. Looking at the job list there were about 23 things which needed work. At least the P&C were good. All turned out well in the end, a good lesson though.

 

[Chris-PA]

I've never used loctite on cylinder bolts, and I've never had one back out.

Put a new piston in it, and you still have a AM topend. Did you contact the seller about this? That should have been disclosed.

Interesting. I only started doing it after taking apart some saws where it had clearly been done at the factory. I believe it was the RedMax saws, but I'm not 100% sure about that either. Anyway, with no locking hardware in a high vibration environment, I don't know what would keep them in.

 

[fearofpavement]

Interesting. I only started doing it after taking apart some saws where it had clearly been done at the factory. I believe it was the RedMax saws, but I'm not 100% sure about that either. Anyway, with no locking hardware in a high vibration environment, I don't know what would keep them in.

Tension from torque. Most things that are held together by nuts and bolts are not "locked". Some critical items are such as on aircraft and so forth. Most of the time that something comes loose, it was because it wasn't properly torqued in the first place.

 

[cgraham1]

Well, Stihl cylinder bolts are "serrated" on the bottom, locking them in place.

 

[Chris-PA]

Tension from torque. Most things that are held together by nuts and bolts are not "locked". Some critical items are such as on aircraft and so forth. Most of the time that something comes loose, it was because it wasn't properly torqued in the first place.

Well, I disagree with that in general terms. Certain fastener types are designed to be anti rotation, and often have larger head diameters, serrations, and/or attached washers, etc. But these are often simple cap screws. Cap screws have a pretty small head diameter, and they are clamping magnesium and aluminum alloys. So you've got different expansion rates and high vibration.

If there was a lock washer, or something, I would not think Loctite would be needed.

 

[jus2fat]

I guess it's just me...but I am just not a believer in these AM "big-bore" kits. Just low quality and too many chances for things to go wrong.

I would never recommend any of them to anyone...If a chainsaw has one on it when brought to me...I just explain and send them elsewhere.

Making a saw a larger saw using OEM parts is completely a different matter.

J2F

 

[roosterhog]

View attachment 348559
Bought this very nice Jonsered a few months ago. It had a lot of compression and ran very strong. I found out after I bought it that it had a big bore kit. I'd rather have OEM, but whatever, it ran good and I was happy with it. I've only ran it a few times.
So, I took it out the other day and fired it up, made a couple cuts, and it died. Yesterday, I put the compression tester on it, 135 psi.
View attachment 348561
I knew something was up, because the rope was much easier to pull than before, but my research said 135-140 was okay on a 372/2171.
View attachment 348560
Well, I decided to pull the jug and the first thing I find is the damn cylinder bolts are loose. I mean way loose! Like falling out, all 4 of them.
This is what I found...
View attachment 348556
View attachment 348558
I guess from now on I'll be checking the cylinder bolts whenever I get a new saw!

Yeah. Dang it. That's the kind of stuff right there that makes me wonder why I don't just have 1 saw like everybody else I personally know and even bother to mess around with a bunch of saws. Hang in there. Take a deep breath and fix it. That is one sharp looking saw.

 

[cgraham1]

I don't think it failed for any other reason than poor installation, and me not checking the saw over good when I got it home.

The saw was really clean and didn't look to be abused at all. I'm not sure why it needed a top end, but I asked the guy about it later and he told me that a "shop" had installed it and he bought the saw from them.

If I'd known then what I know now, I would've asked more questions, and I probably wouldn't have bought the saw.

 

[weedkilla]

Well, it's in bits now, it has an am cylinder of minimal value, it's time to get porting!!!!!!

 

[nmurph]

I've never used loctite on cylinder bolts, and I've never had one back out.

Put a new piston in it, and you still have a AM topend. Did you contact the seller about this? That should have been disclosed.

Ditto.

 

[cedarshark]

I had this happen to me recently on an 038. Had a Chinese cheap kit. I tore it down cleaned the parts really well and sold it for a parts saw, noting it had an am top end. Made $30 but glad to see it go.

 

[burnses]

on the up side at least you figured it out before it really blew up! As to the cylinder bolts....a bolt in that situation stays tight by the stretch on the bolt when it is tight. That means the bolt needs to be tightened enough to stretch the bolt longer so it is in tension....that's why there are torque specs to get enough tension on the bolt.....I have found that if you retorque to tighten the cylinder bolts after break in and the gasket settles then that's it it'll stay tight.

good luck