Confusing problem with my MS 261 after changing sprocket and bar

[Harlen]

I had a very large diameter liveoak to drop, and I changed the 20" bar to a 25" to help with the back-cut. I thought I needed to change the sprocket to do this, and it worked fine, and the tree is down. I just changed back to the original bar and sprocket it, and it seems as though the chain runs roughly through the bar? That is, after changing it back it doesn't seem to run as freely through the bar, and it makes an awful sound when I spin it backwards. I am just turning it by hand while off.

I am afraid that running the different sprocket may have caused some damage; can anyone here make sense of this issue? I will be very grateful as I need to buck up that tree soon! Thanks in advance for any sage advice; this seems like a great forum, Harlen.

 

[ballisticdoughnut]

Can you post a picture of the clutch side of the saw with the clutch cover off? Wondering if something got reassembled incorrectly.

 

[Harlen]

ballisticdoughnut wrote:
"Can you post a picture of the clutch side of the saw with the clutch cover off? Wondering if something got reassembled incorrectly."

Thanks for the prompt reply, and willingness to help. Sorry to say my computer skills are pretty weak. As for the changing of the sprocket, it was as simple as popping off the little keeper, and lifting off one sprocket set up, and putting the other one on.

I have tried taking the bar on and off, loosening the tension, and it still makes a clicking sound when I spin the chain backwards, and just doesn't want to go that way. I just tried something else, and got these results: I put the larger sprocket back on, and it spins forward and backward very smoothly.
The original sprocket that goes with the 20" bar is a 325-7, and the other sprocket that I used with the 25" bar is a 3/8-7. I hope that helps sort this out.
Thanks again, Harlen.

Note: I mean that I put the 3/8-7 sprocket on the MS 261, and put the 20" bar on it, and it seems to spin perfectly. Is there any reason not to just use this 3/8-7 sprocket tomorrow, until I figure out why the stock 325-7 doesn't work?

 

[Mad Professor]

Did the 325-7 sprocket ever get ran with the 3/8-7 chain/bar?

Check that things are assembled correctly. I think the oiler drives off the clutch drum on that saw. Make sure the spring is in the slot/notch in the drum.

This is a picture from a 036 clutch. You can barely see the notch in the drum on it's rim, just below the brake band at ~ 4 o'clock.

 

[ballisticdoughnut]

ballisticdoughnut wrote:
"Can you post a picture of the clutch side of the saw with the clutch cover off? Wondering if something got reassembled incorrectly."

Thanks for the prompt reply, and willingness to help. Sorry to say my computer skills are pretty weak. As for the changing of the sprocket, it was as simple as popping off the little keeper, and lifting off one sprocket set up, and putting the other one on.

I have tried taking the bar on and off, loosening the tension, and it still makes a clicking sound when I spin the chain backwards, and just doesn't want to go that way. I just tried something else, and got these results: I put the larger sprocket back on, and it spins forward and backward very smoothly.
The original sprocket that goes with the 20" bar is a 325-7, and the other sprocket that I used with the 25" bar is a 3/8-7. I hope that helps sort this out.
Thanks again, Harlen.

Note: I mean that I put the 3/8-7 sprocket on the MS 261, and put the 20" bar on it, and it seems to spin perfectly. Is there any reason not to just use this 3/8-7 sprocket tomorrow, until I figure out why the stock 325-7 doesn't work?

That saw should have come stock with .325 pitch chain. The rim sprocket, bar, and chain need to match. If you’ve got the 3/8 pitch rim on it now with .325 chain they won’t mesh correctly and you’ll end up ruining both if you run it that way.

 

[Harlen]

I wrote:
"I put the 3/8-7 sprocket on the MS 261, and put the 20" bar on it, and it seems to spin perfectly. Is there any reason not to just use this 3/8-7 sprocket tomorrow, until I figure out why the stock 325-7 doesn't work?"

I believe I had this sprocket installed in an old 311 saw, which strangely came equipped with a 25" bar. I wanted to use it for dropping a big tree, but knew that it would run much better with a 20." I think the guy at the saw shop said that I could have a sprocket that would run either the 20" or the 25" bar. Does this 3/8-7 have that ability, and if so, is it alright to just leave it on the new MS 261,since unlike with the 325-7, it seems to turn the chain smoothly, both forward and backwards?

This all happened the night after I finished working the saw with the 25" bar, and it cut well enough today. I am afraid to try the saw with the 325-7 for fear of causing some damage. What whould you recommend? It is probably obvious by now that I am not an experienced saw mechanic-- far from it. Once again, many thanks for the support, and advice.

Ballisticdonut, I didn't see your reply above till after I wrote the this comment. I must check to see if those 3 all line up....

 

[Harlen]

Thank you BD! You have sorted me out. I just have too many bars and chains, and not enough sense to keep them in order. I did get two 3/8" setups-- one for the 25", and one for the 20." My mistake was grabbing the 3/8" bar and chain instead of the 325 when I put the 20" bar back on the new saw with the 325 sprocket. The 325 sprocket and chain were in the truck, as a backup.

What a relief not to have damaged something by switching to the 25", because the chain, bar and sprocket were all 3/8."
This is a great forum, and now I need to contribute something in appreciation. Harlen.

 

[ballisticdoughnut]

Glad to hear it.

 

[fields_mj]

That's why all of my bars and chains that are 20" and under are .325. Makes it rather difficult (but not impossible) to have a mismatch, and it's easier for me to have spare parts available if I'm in a bind (pun intended).

 

[buzz sawyer]

Glad this worked out for you. Side note, the 25" bar is a little much for the 261. Don't force it in the cut and make sure the chain is sharp. Turn the oiler up to max if not done already.

 

[Harlen]

All good advice, and appreciated. I used the 20" for the face cut on a gnarly old oak with 40" butt, the 25" really helps on the back cut. The hinge had to be just right to pull the tree away from the house. I have used the 25" with good (though slow) success falling some pines and redwoods, but the burly liveoak was really slow going. I just don't do enough tree work anymore to warrant a MS 462, or whatever the 400 series numbers are.
I have a lot to learn about maintaining saws, and even more basic stuff, as my recent problem shows. Thanks for the advice and support, Harlen.