066 troubleshooting

[Exmasonite]

Hey everybody... having a little issue with my 066 and looking for advice.

First question: Are there different sized bar nuts? I stupidly dropped one off the bench last night and stopped by the shop to pick another one up today. So, i had some trouble getting the replacement on. To be honest, i was in a bit of a hurry today (out to cut some scrounge) and just threw it on there. In hindsight, the bar nut wasn't on very tight and I think it's because the threads weren't matching up. As in, i put it on until i got resistance, but it wasn't on very tight. So, are there different sized bar nuts or is the bar "bolt" getting stripped?

So, this leads me to my 2nd question:
The chain tensioner broke, twice. The first time, i figured was my fault. Again, probably taking things for granted and over tightened last week. Couldn't get around to picking up a new one until today. I also picked up a replacement sprocket since the guy at the shop said it looked worn. Tension post broke like in the first picture below. So, replaced that piece of metal, also replaced the metal threaded bolt underneath since the one in there seemed a little bent/warped. Put both of those on and went cutting, along with my new bar nut that wasn't seeded right. Here's what happened:

I was cutting for about 1/2 hr, everything going fine when all of a sudden the chain (newly sharpened, btw) jumped off the bar and bound while cutting. I think the chain and bar may be pretty screwed up... the chain is stuck in about 1/3-1/2 the bar and the under side of the chain looks chewed up. That may be due to the old worn sprocket it was running on but it's a pretty new chain.

So, here's what i found upon inspecting the saw: One of the bar nuts (the old one) had fallen off and the tensioner was broken AGAIN, same as first one. In addition, the newly purchased tension screw was broken (see 2nd pic).

Here are the rest of my questions (aside from whether i might have the wrong bar nuts. If it matters, the bar nuts thread VERY well on my 260 pro):

1) I can make the case that this is all related to using the wrong bar nut which didn't seat well and allow enough vibration for the other bar nut to come off which put a LOT of instability in the bar and broke the newly replaced tension parts.

2) Is there anything ELSE i should be worried about? As in, persistent breaking of tension apparatus is indicative of some other problem?

 

[smokinj]

I would like to see the sprocket? Fool me once............

 

[Exmasonite]

will work on getting some pics of the chain and sprocket, jay

You think they gave me the wrong sprocket? Could that explain the issues, too?

In the "sprocket's" defense, the first tensioner broke on the old/original sprocket. but then again, i am not sure if tensioner broke and then i tried to tighten chain or if my tightening of the chain caused the problem. Last week, chain seemed lose so i tightened it but it didn't run for very long after that so maybe tensioner was already broke?

Also, any answer on whether bar nuts are universal or if i could have the wrong one?

 

[Exmasonite]

Alrighty... snapped a few more pics. First 2 are of the sprocket.... old sprocket on the left, new sprocket on the right. I think they're pretty much identical.

Third picture is the SHREDDED chain. It was jammed in bar good but i think it's just the chain. I took another chain and put it on the bar and i think the bar will be ok... but chain is done. I imagine the sprocket just shredded to chain once it loosened up too much.

 

[Naandme]

My first thought is slow down before you get hurt. And then before you go out to cut make sure the equipment is ready not half ready. Look at the new sproket and tensoner as a cheap lesson. By not doing proper maintenance the chain could have fliped off and whacked you which could have been a disater. So now you are going for a new bar, chain, sproket, and tensoner. And maybe 2 new bar studs if the pic is acurate which all this maybe could have been avoided if you had fixed the one that was loose the first time. My point to this is, The saws need preventive maintenance, cleaned, adjusted, and sometimes rebuilt. If we fall to do that they will let us down and can even hurt or possibly kill us. I am glad you didnt get cut by the chain when it kicked off (chain catcher must have been on saw) seen a chain flip off and cut a old boy wide open by just the slap of the chain. PLEASE BE CAREFUL and PROPER PREVENTIVE MAINTENANCE!!

 

[smokinj]

WOW That chains a mess! Is there a chain catcher on this saw?

 

[Danno77]

WOW That chains a mess! Is there a chain catcher on this saw?

hope so, $10 can save some pain.

 

[smokinj]

WOW That chains a mess! Is there a chain catcher on this saw?

hope so, $10 can save some pain.

Lots of things going on here....lol

 

[southbound]

All I can say is WOW..............

 

[Danno77]

you aren't cranking the chain tensioner with the bolts tight on the bar? I just have to ask cause that's one way to break a tensioner.

 

[holland_patrick]

That's what i was thinking also but he did say it the nut seemed loose?

 

[Danno77]

That's what i was thinking also but he did say it the nut seemed loose?

yeah, you are right. I would think that a loose nut would mean a lot of pressure was on the tensioner when you were pressing down on the bar. I bet that IS how it busted. so, 1st thing on the agenda is getting that nut on there secure. Might mean you need a new set of bolts.

 

[holland_patrick]

I'd love to help out there I know we both have week days off and i have a to stihl dealers close to me so if you want to come over we can have a crack at it.. something has to be very wrong to crack both the bolt and the tensioner

 

[southbound]

I just went threw this with my 440 mag at work...

The chain was stretched beyond the travel of the adjuster and I was miles away from the truck and a new chain. So what do you do ?? I gave it on last try to tighten the chain and to my surprise it did.... The next day I start off by installing a new chain and I notice that the chain adjuster is not moving freely... What had happened was when I over tightened the adjuster (the piece with the pin for the bar) bent.. It now was bent towards the nylon part and was binding...

So here I can see if the adjuster is bent and caught on either on the nylon or the metal cup that covers the worm gear and it is forced something will break..... Or maybe it is not bent but the nylon or worm gear cover is stuck out from something behind it????

 

[Battenkiller]

Ha, ha! That chain looks like the chains my buddy uses on his Dolmar 7900. He runs 3/8" lo-pro with a 16" small tip radius hard-nose carving bar on his woods ported saw. That saw just tears up the drive links way before he ever runs out of cutter plate to sharpen. But he gets about $5000 worth of bears carved with one before it craps on him, so it's still good economy because the big saw cuts so much faster and he can make more bears in a day.

 

[Exmasonite]

Quick update:

So the root of my problem seems to be the bar studs. Can't get any replacement bar nuts to fit on the studs well. Ordering a new pair of those. I think my old bar nuts that came with the saw (one of which i'd lost) had somehow become reprofiled to work "well enough" on the stripped studs.

I think the problem was that i tried to tighten down the bar nuts and the studs were stripped so the nuts couldn't seat well and the case was loose, allowing WAY too much play on the bar and tensioner. I THOUGHT i'd tightened the nuts since i got resistance.

Naandme- Thank you for the advice and insight. I will tell you that I keep very clean gear and am pretty meticulous about keeping all of the gear clean. If it looks dirty in the pics, it's b/c i'd just gotten home from cutting and snapping pics was the first thing i did. I am also a pretty thorough person... i think i got faked out by the stripped studs, lesson learned. I always wear full safety gear and go pretty slow, especially since I am still learning.

One thing the saw doesn't have is a chain catcher... so that's the 2nd thing on order with the bar studs. I was lucky... didn't get hit by the chain when it jumped. I did have full chaps, arm/torso guards, helmet and face shield on so I'd like to think i was as covered as possible.

Going to get the new bar studs in and replace the tensioner system. I think the sprocket looks ok and the guy at the dealership agreed. Any opinions on that front?

Will keep you guys posted and appreciate all the comments.

 

[smokinj]

Quick update:

So the root of my problem seems to be the bar studs. Can't get any replacement bar nuts to fit on the studs well. Ordering a new pair of those. I think my old bar nuts that came with the saw (one of which i'd lost) had somehow become reprofiled to work "well enough" on the stripped studs.

I think the problem was that i tried to tighten down the bar nuts and the studs were stripped so the nuts couldn't seat well and the case was loose, allowing WAY too much play on the bar and tensioner. I THOUGHT i'd tightened the nuts since i got resistance.

Naandme- Thank you for the advice and insight. I will tell you that I keep very clean gear and am pretty meticulous about keeping all of the gear clean. If it looks dirty in the pics, it's b/c i'd just gotten home from cutting and snapping pics was the first thing i did. I am also a pretty thorough person... i think i got faked out by the stripped studs, lesson learned. I always wear full safety gear and go pretty slow, especially since I am still learning.

One thing the saw doesn't have is a chain catcher... so that's the 2nd thing on order with the bar studs. I was lucky... didn't get hit by the chain when it jumped. I did have full chaps, arm/torso guards, helmet and face shield on so I'd like to think i was as covered as possible.

Going to get the new bar studs in and replace the tensioner system. I think the sprocket looks ok and the guy at the dealership agreed. Any opinions on that front?

Will keep you guys posted and appreciate all the comments.

Very difficult to say much unless your on the saw...Chain catcher is a big step in a few ways. Look at the bar to see that its straight and true. Do not have much beyond that. Its just one of those things for a chainsaw Operator that has your head scratching WTF?