Chainbrake/Clutch drum contact issue

[nnero]

I recently sold my 120si locally. I explained that if anything went wrong with the saw right away and it wasnt something he did stupid, I would make it right. Maybe thats too far to go with a craigslist sale but i feel its the right thing to do. Especially since the fellow had one of these saws in the past and was excited to get one again (If I got a bad vibe I wouldn't have made that offer). He also has a Dolmar 420 and Husqvarna 2100.

Anyways, he ran a few tanks through last weeked and emailed me that the clutch cover was getting very hot. We eliminated operator error (chain tension, leaving brake on, pusing too hard, dull chain etc). The brake handle engages and disengages properly. But you can see where part of the brake band is rubbing on the drum.

I didnt notice this issue when I used the saw but I replaced clutch shoes, spring, drum and bearing before I sold the saw and didnt run it in wood. My first terrifying thought was crank bearing but that doesnt seem to be the case. I picked the saw up and am going to look into this week. I ll get some pictures when i get into it. I want to be timely so I thought I would try to get some suggestions. Thanks

 

[Mastermind]

I'm not sure if the band is adjustable on that saw. It is on a few others though. The 3120XP comes to mind.

 

[Mastermind]

You might post this queary in the Dolmar thread in the Brand Specific area......

 

[Adirondackstihl]

@166
@cuttinscott

 

[jacob j.]

Look to see if the brake band has a slight bend in it anywhere that is causing it to contact the drum. That's the most common cause.

 

[Adirondackstihl]

Perhaps the drum has a slightly larger OD?

 

[nnero]

Thanks I will look into all that. I do have an extra chainbrake to compare to. Since it is only rubbing on one spot of the band maybe it is a bend or tweak.

 

[old guy]

Once when converting a 5020 poulan to .325 chain I got the proper echo clutch drum that others were using, it was an after market Oregon drum and the pressure of the clutch would expand it enough to reach the brake band causing great warmth in that area, I just went back to .375 chain.
Others were using genuine echo drums were not having the problem.

 

[Adirondackstihl]

Any aftermarket drum I have tried in the past year or two have had fitment issues.
To the point where I would prefer a used OEM over new AM.

Not saying you used AM, but if you did it may be something to look into.

 

[nnero]

I think it was an oregon. I have to dig around and see if I can find the original

 

[nnero]

I found the original drum so now I can compare everything

 

[Backtroller]

I had a Farmtec 024 clutch drum that gave me grief.

Any aftermarket drum I have tried in the past year or two have had fitment issues.
To the point where I would prefer a used OEM over new AM.

Not saying you used AM, but if you did it may be something to look into.

 

[nnero]

Started to look into this. The drum only contacted the band at the top portion, where the band connects to the spring. There was no contact on 50% of the band. If it was a drum or bearing issue then it should have been rubbing across the entire band?? I'm gonna have to swap the brake band too because it's thinned at the trouble spot.

What I'm gonna do first is mark the band on my spare cover with a sharpie and then run the saw and see if and how the marks are affected. That should tell me of the band or the drum is the problem. I will update with pics later. I hate issues like this...I'm so glad I sold this saw locally and didn't ship it half way across the country. I would feel like a real scumbag

 

[nnero]

Ran it some with the spare cover after marking the band. Didn't have any wood to cut so so just ran it for a minute or too. The cover did start to get warm to the touch. How hot does a cover get normally?? There was slight rubbing on the 12:00 mark I made. Both drums are the same Oregon number and measure the same with calipers. Both for onside the band disengaged with room to spare. Crank bearing is toght, and there is a slight wobble with the drum on. New bearing too. I don't know what to do next besides run it in wood myself. The first pic shows the wear/rubbing on the original band. It's the area between my marks. There is no running on any other part of the band. You can see the excessive wear on the band where I am pointing.