Need help with odd chain tightening issue

[cjnspecial]

So my chain tightens up significantly after adjusting it and I'm stumped as to why.
Brand new 3/8 rmc chain.
Bar is excellent shape, chain runs freely through the rails when off the bar with no wobble.
Swapped rim out and it still does the same thing.
Bar and chain are both 3/8-.050. Rim is 3/8-7


<iframe width="560" height="315" src="http://www.youtube.com/embed/TjKkue4R2RY" frameborder="0" allowfullscreen></iframe>

 

[old 040]

this would normally indicate a worn sprocket, but as you stated, a new rim installed, i would try a differant chain. was the new chain premade or put together?:msp_confused: would also suggest wearing gloves when working with chainsaw chains

 

[Fish]

take a close look at the chain, take a close pic, or tell us what numbers you can see, same as bar and rim.

 

[jus2fat]

Good video actually showing your problem.

Having changed the rim...got to be a chain problem.

Is that a Stihl manufactured chain or some other brand..??
(Stihl chains are supposedly pre-stretched)..??

J2F

 

[brokenbudget]

could be your not tightening the bar as much as you shoud be. if you lift the end of the bar 'up', the chain will loosen a bit. if you push it down it will tighten. are you doing under cuts when this is happening?

 

[In The Weeds]

I agree about wearing gloves when handling the chain on the bar, I've learned that the hard way and gotten some good slices as a result. I also would tighten the chain with the bar resting on a block of wood or something holding the bar up like the last guy said cuz this has happened to me as well but went away when I paid more attention to the angle of the bar

 

[cjnspecial]

take a close look at the chain, take a close pic, or tell us what numbers you can see, same as bar and rim.

Bar is 3/8 050, # is 3003 000 8822. Chain says 3/8. It's a brand new loop of rmc3. I thought it was the chain at first and swapped from an old loop of rsc to this chain and it's doing the same thing. The rim is a 3/8-7 oregon. The oiler is working great too.

 

[Fish]

It is an oregon rim, on a Stihl sprocket? That may be the problem.

 

[cjnspecial]

It's a pre-made loop. I normally wear gloves, can't find em though....they are probably underneath my 3 year old's bed. :hmm3grin2orange:

 

[brokenbudget]

It is an oregon rim, on a Stihl sprocket? That may be the problem.

i doubt that.

 

[Fish]

i doubt that.

Why is that?

 

[cjnspecial]

It is an oregon rim, on a Stihl sprocket? That may be the problem.

The stihl one was doing the same thing. It had a little wear on it but wasn't wore out.

 

[bushwackr]

make sure ur oiler is working , mine 036 did funny chain tension things when the pump was bad. It was still oiling just not properly, or check out the sprocket in the nose of the bar.

 

[Fish]

So it is an Oregon rim on a Stihl sprocket?

 

[Fish]

take the new one off and sit it on top of the old one.

 

[Fish]

Here is a pic of an Oregon small spline next to a Stihl.


View attachment 211900

 

[cjnspecial]

Here's a pic showing the wear on the old rim.

View attachment 211902View attachment 211902

 

[Fish]

Looks like a Stihl rim.

 

[brokenbudget]

Why is that?

if the rim fits properly (never once in 20 years seen one that didn't between stihl and oregon) and is perfectly round, why would it?
this sounds like a tightening issue, either the inner bar plate is hiding a bunch of crud behind it and not letting the bar to be tightened properly or he just isn't tightening the bar properly. if the chain isn't stretching, and the clutch is still in the same place, that only leaves either the adjuster isn't holding the bar in place, or he's grinding the chain and bar to dust form lack of oil. if everything is kosher with the parts, the only way for that chain to become loose (other than stretch) is for the bar to move either in/out or up/down.
lots and lots of stihls out there that don't have the oem clutch drums and spurs brand matched and they seem to just tick along just fine.

 

[zr900]

Here is a pic of an Oregon small spline next to a Stihl.


View attachment 211900

Fish

Your pic shows a 3/8 and a .325

my 3/8 pin rims in stihl and oregon look identical other than the name.

I have also heard that oregon makes the rims for stihl.