Chain slack driving me crazy......

[avalancher]

This week I am working with some logs that were dragged a bit through the mud, and even after a good bit of brushing they dull the chisel chain quickly, so I stopped by the local saw shop and picked up two new semi chisel chains, one for the 455, one for the 372.
Used the 455 first, and after 30 seconds of sawing, the saw bogged down. Pulled it out of the log, chain was too tight. No problem. Loosened the chain up and went back to work. then the chain was too loose. Okay, I loosened it up too much, right?
Back to the truck, tightened just a smidge, and spun the chain around the bar.then right before my eyes, the chain tightened itself to the point I could not run the chain by hand. I took the cover off, examined and cleaned everything and reassembled. Still the same thing.
Set the 455 aside, mounted the other new chain to the 372 and the same results. The chain can be slack enough to have a droop, but if you turn the chain by hand, it will tighten back up to the point that you cant turn it any further by hand around the bar.
Okay, what the heck is going on here? I have never seen anything like it. Anyone got any ideas?
Just a side note, the chain had been sitting around the shop of over 6 years according to the guy behind the counter, he said he never sells semi chisel anymore, and I was the first to ask for it for 6 years. He really had to search for it to find the reel. It was covered in dust, and I gave it a good cleaning with solvent before I tried it out.

 

[super3]

check drivers

Wrong gage drive links? .063 maybe

 

[Kneejerk Bombas]

That sounds like what happens when you are not getting oil.

 

[avalancher]

Wrong gage drive links? .063 maybe

There is no stampings on the drive links, even though this is supposed to be an Oregon chain. The box was handwritten 72LG84. I thought the 72 series was .050 gauge. If the gauge was too big, it wouldnt fit between the rails, would it?

 

[blsnelling]

A few things to check for come to mind.

1. Check your chain to make sure it isn't dry and kinking
2. Check your sprocket to make sure it's not worn out and binding the chain
3. Bent crankshaft

 

[Torquin]

I'm with Super3, but I think he means pitch. If you have the incorrect pitch chain for your sprocket it will be loose when the drive links are seated just right in the sprocket but as the chain moves around the drive links will ride up the sprocket teeth and tighten the chain on the bar.
That's the first thing I'd look for.
Then there would be a bent crankshaft, or the sprocket bearing on the clutch going bad, causing the clutch to no longer run true.

Chris

 

[Log Splitter]

He had the same results on two different saws, so I doubt he's chasing a saw problem.

Wrong pitch chain.....

 

[Zodiac45]

72 is 3/8 chain. Is that what you run on your 455? If so then I would check my sprocket drive next. That maybe worn, or the chain is not seating quite right into the spur or floater. You are right 72 is 50 gauge and anything else wouldn't fit the rails of your .50 bar. You said no markings at all on the drive links? That's strange but I can tell you that I've had that very same problem on my motorcycle when my chain wore out. I couldn't adjust it properly same as you. In one position it was perfect and when I spun the wheel it would tighten up due too chain stretch or bound links. I'd take it back and get replacments. Let us know what the outcome is.

 

[huskydave]

He had the same results on two different saws, so I doubt he's chasing a saw problem.

Wrong pitch chain.....

+1 check the box .404 instead of .375.

 

[Zodiac45]

+1 check the box .404 instead of .375.

Good call Dave. Bet that's it.

 

[cuttinscott]

There is no stampings on the drive links, even though this is supposed to be an Oregon chain. The box was handwritten 72LG84. I thought the 72 series was .050 gauge. If the gauge was too big, it wouldnt fit between the rails, would it?

you have been dooooped, All Oregon chain has id numbers on the drive tangs, sure you have a Oregon box but not a oregon chain, you either have wrong pitch like .325 instead on .375 or like dave sain you might have .404 instead on .375 or wrong gague like .058 or .063 instead of .050 post a pic



Scott

 

[super3]

If the gauge was too big, it wouldnt fit between the rails, would it?[/QUOTE]

Depends on how bad the wear on bar is. .063 will go into an .050 worn out bar but it won't spin well

 

[SteveH]

These guys gotta be onto the answer. I don't see how you'd have bent cranks on BOTH saws. That would be one for the record books. And you'd likely know it anyway. Same with the sprockets. Both saws? Oil? Not the problem if you are just pulling the chain thru by hand just after setting up the saw. I'm bettin' on it being the wrong chain in some manner. But this is a really interesting post and series of opinions, I'll be watching to see what the final answer is. By the way, seems to me the shop would know the chain. I'm not accusing anyone of anything [yet], but you go to a pro to know what he's doing.

 

[spacemule]

Worn sprockets will cause that, and it's very likely that both saws have worn sprockets.

Overheating a chain and then tightening it up and then leaving it tight has been known to bend cranks. In that sense, it is not inconceivable to have two bent cranks, but I doubt it. I'd check the sprockets.

 

[docshank]

Either the wrong chain or a worn sprocket

Your saws weren't giving this type of problem before you started using the chains in question, right? Also remember when you roll the chain around the bar by hand, the crankshaft is not even being turned, only the clutch hub. Forget about a problem with the crankshaft.

docshank

 

[maccall]

The chain can be slack enough to have a droop, but if you turn the chain by hand, it will tighten back up to the point that you cant turn it any further by hand around the bar.

I have experienced the exact same thing, only difference it's on my Stihl saws!!!

I bought a new 15" Stihl bar for my 026, and a new 16" Stihl bar for my 250 together with 2 26RMC and 2 26RSC chains, and the purpose was to be able to switch chains between the two saws (the bars are actually the same lengths). I also got a new clutch drum and rim setup for the 250 and a new rim for the 026.

However, I was close to going berserk when trying to tighten the chain, it just wouldn't do! If I go back to the old bars, chains and drive sprockets the problem is gone, so whatever it is, it does not seem to be the saws.

I was just out in the shed checking on the 250 and the difference is quite big: When the chain is the most saggy the whole drive tang comes out of the groove, and when it's the least saggy the chassis of the chain are flush against the bar rails. I'm pretty sure both saws were the same, but for now I only confirmed on the 250.

As I couldn't find an explanation to this I decided to just don't care, I've tightened the chain so that it still rotates freely from hand power, and it hasn't been thrown yet. Don't look too good but since it cut's wood I'm just ignoring it.

 

[avalancher]

I listened to all your suggestions, and here is what i did to eliminate what I could.
First, took both bars off, cleaned all the rails and dressed them. Greased the nose sprocket, cleaned the oil ports and inside the side cover. Blew it all out with compressed air. Ran both saws with the nose down at a piece of cardboard, both spraying oil.
Next, I called the shop where i bought them, and had the read to me what it said on the spool. .375 pitch, .050 gauge.
Then I explained the problem to the owner. He said it was the sprocket.
Naw, maybe on the 372, its getting a little worn, but the sprocket and the bar on the 455 have less than 10 hours on both. Replaced them both at the same time last month.
he said, oh, you have sawdust stuck in the front nose sprocket. On both saws? Yep, thats it. Explained that I cleaned everything out, blew it out, and reassembled everything. Also, both saws running full chisel do the same thing, they both work fine until I mount the semi chisel.
he then said something really stupid like maybe my saws were not set up to run semi chisel......:censored:
then I asked him why every oregon chain I have ever had in my lifetime had markings on the drive tabs, and these chains do not. Had him look on the spool that he had, no markings on the drive tabs. Then had him look at all the rest of the oregon chain that he had in stock, all had markings on the drive tabs.
I am beginning to suspect that someone coiled a chain other than what was supposed to be on that spool, and sold it off. On purpose? dont know. I told him that i would be down there in the morning with both saws in tow so that he could take a look at em.
Thanks for all your suggestions and thoughts on the matter. I will post what comes of it tomorrow morning.

 

[avalancher]

Oh, and by the way MCCALL, that little bug down in your signature drove me crazy! Thought it was a bug on my screen, took two stabs at it before I realized that it was a ghost I was chasing.

 

[Mad Professor]

+1 check the box .404 instead of .375.

I don't think it's 0.404 as it's (0.404) 0.063 gauge (or 0.080 harvester) and would not fit the bars 0.050 gauge groove.

Any chance he sold you a "picco style" 3/8 0.050 ? Picco runs different sprockets.

 

[avalancher]

I don't think it's 0.404 as it's (0.404) 0.063 gauge (or 0.080 harvester) and would not fit the bars 0.050 gauge groove.

Any chance he sold you a "picco style" 3/8 0.050 ? Picco runs different sprockets.

Okay, you are going to have to educate me on this one, what is a Picco style chain?
Please excuse my ignorance! I have heard the term, but dont know what it is.