Chain stretch, already?

[precaud]

Sounds to me like he is only turning the drive gear not the entire crankshaft. That in itself would eliminate the bent crank theory.Yes?

Yup, you're right...

So either a 325 on a 375 or a hunk a crap in one of the sproket slots

Nope, neither...

The bar sprocket is fine, so, as Holmes would say, what remains must be the truth

 

[Crofter]

I would get the sprocket off and examine it closely. Make sure the internal spline size is correct too. I have seen some runout on new sprockets.(aftermarket more so than OEM) but not so bad as to give the slack you picture. If the loose and tight spots are always in the same place on sprocket rotation, that kind of narrows the spot to look for the problem.

 

[jhellwig]

My 260 does that same thing. Usually it takes several rotations to get it to happen though. It has done this since I bought it new. Just another reason for me to like hard nose bars.

 

[SawTroll]

There should be play sideways, if it is a rim, but not front to back - sounds like the rim is for a larger spline than is on the saw.......

..does the 401 use the same "mini-7 spline" as the 026 and 024, and not the regular "small-7 spline" ?????

 

[Engineeringnerd]

My saws sometimes does this also. For me it has usually been one of the following:

1. I didn't keep the tip of the bar up while tightening. I now always hold the saw handle in one hand, and put the tip of the bar on a table or tree while I tighten the bar nuts.

2. I've had the chain only partially engaged in the rim sprocket or the nose sprocket. With a partial turn or two, the chain falls into the sprocket making it loose. I now turn the chain about a full rotation to get the chain seated in the nose and the rim sprocket.

3. I tried to make a "fine-tune" on the adjuster without fully loosening the bar nuts. I think it results in a little wiggle room that allows the bar to slide under stress. Now I pretty much adjust the chain so it fully touches the bottom of the bar with the bar nuts finger tight, then tighten fully with the wrench. This results in it lightly "snapping" when plucked.

 

[SawTroll]

....

3. I tried to make a "fine-tune" on the adjuster without fully loosening the bar nuts. I think it results in a little wiggle room that allows the bar to slide under stress. Now I pretty much adjust the chain so it fully touches the bottom of the bar with the bar nuts finger tight, then tighten fully with the wrench. This results in it lightly "snapping" when plucked.

On some saws, you need to use a bit of "Kentucky windage" as the chain tightens up a bit when doing the final tightening of the nuts - but that is not the issue here......:biggrinbounce2:

 

[oldsaw]

On some saws, you need to use a bit of "Kentucky windage" as the chain tightens up a bit when doing the final tightening of the nuts - but that is not the issue here......:biggrinbounce2:

Wow, a Norwegian talking about "Kentucky windage"...it's a cool world we live in when such phrases are "wordwide". You tend to "get a feel for it" after a while, Precaud, which is exactly what "Kw" is. You just kind of know where you need to be. Each saw is a bit different, with each bar length, and even with each bar.

Mark

 

[Fish]

Ky. wind?

 

[clearance]

On some saws, you need to use a bit of "Kentucky windage" as the chain tightens up a bit when doing the final tightening of the nuts - but that is not the issue here......:biggrinbounce2:

Some saws, you mean Stihls, Huskies don't do that. They stay where they lay.

 

[precaud]

On some saws, you need to use a bit of "Kentucky windage"

Hmmm... sounds like something I'd rather be upwind of...

as the chain tightens up a bit when doing the final tightening of the nuts - but that is not the issue here......

Correct. My old 011 did that, but not the 401.

 

[precaud]

..does the 401 use the same "mini-7 spline" as the 026 and 024, and not the regular "small-7 spline" ?????

I don't know if it's an Oregon part, as you're suggesting, I think. The Oregon website shows no sprocket part numbers for it.

 

[precaud]

My saws sometimes does this also. For me it has usually been one of the following:

1. I didn't keep the tip of the bar up while tightening. <snip>

I'm very conscientious of that...

2. I've had the chain only partially engaged in the rim sprocket or the nose sprocket.

Double-checked that too. It's a spur sprocket, btw...

3. I tried to make a "fine-tune" on the adjuster without fully loosening the bar nuts.

I'd NEVER do that!

Now I pretty much adjust the chain so it fully touches the bottom of the bar with the bar nuts finger tight, then tighten fully with the wrench.

Exactly my technique, as well.

 

[scottr]

I'm very conscientious of that...


Double-checked that too. It's a spur sprocket, btw...



I'd NEVER do that!

Exactly my technique, as well.

How deep are the wear marks on the spur ?

 

[precaud]

How deep are the wear marks on the spur ?

It's brand new - I don't see any.

 

[PES+]

I would remove the clutch and check the drum/spur AND the needle bearing and cage

 

[SawTroll]

I don't know if it's an Oregon part, as you're suggesting, I think. The Oregon website shows no sprocket part numbers for it.

As far as I know, Oregon doesn't offer rims for the mini-spline - Stihl does.

I don't know much about spurs, if that's what is on the saw.........

 

[SawTroll]

Some saws, you mean Stihls, Huskies don't do that. They stay where they lay.

In my case, it is the Stihl 353 then..... :rockn: :rockn:

 

[Fish]

Sounds like the trouble is at the sprocket. I am not familar at all with
Dolmars. It sounds like it might be an incorrect sprocket, and by now has
damaged the needle bearings as well. It is probably a spur sprocket, but
that is just a guess. Remove the sprocket, and post a pic and any numbers you can find, and maybe one of our Dolmar experts will chime in.

 

[precaud]

Thanks to everyone for your input. I've written to the dealer and am awaiting their reply.

 

[precaud]

While I'm waiting for the dealer to reply... I examined things more closely last night and the slop is not all caused by the drive sprocket - some may be in the nose spocket also. So I got out my caliper to measure variations in the spurs.

I'm not clear about what variations I should be looking for: in the height of the spurs, the width of the spurs, or in the depth of the valleys between them? (Feel free to correct my terminology...)