Duff Bar/saw?

[Spencer]

Ive just replaced the 20"bar and chain on my stihl MS360 cause it was getting really hot and I thought I`d bent it.
BUT the new bar does just the same!! I cant understand why its getting so hot. The chain sprocket/clutch is all too hot to touch.
The oil is feeding onto the chain and it seems to cut ok, so what could be causing the problem...? Would appreciate to hear from anyone with any ideas....Thanks

Spencer.

 

[ORclimber]

Bent chain brake strap rubbing against the clutch assembly? Had that happening on a husky 266.

 

[Ryan Willock]

How tight do you have the chain?? Is the bar groove the right size for the chain gauge or vise versa??? Do you have the oiler turned up enough?? Are you using BAR oil (not motor oil or transmission fluid!!)??? Is your chain sharp? If not then you are probably pushing the saw through the cut. Is the bar sprocket working properly??

 

[Spencer]

The chain/bar/sprocket are all matching 3/8 pitch, the oil is turned up to full (stihl chain oil) and the 20"rollomatic E bar and Rapid super chain are all new. The bar gets very hot when just revving the saw for a few minutes.
The only thing I didnt change was the sprocket which has some wear . maybey the chain isnt running smoothly on it and so generating alot of heat??

 

[cbfarmall]

I agree with ORclimber. An Echo I was working on did the very same thing and I found the chain brake strap to be too tight. A quick glance at the drum showed where the strap was rubbing. My main concern, unfounded or not, was that the sprocket would get too hot and damage the crank seals. See if you can temporarily bypass the brake.

I imagine that a messed would make a whole lot of racket and mess up your chain before it ever got really hot.

Is the chain hard to pull around the bar by hand? Do you have to rev the engine pretty high before the chain starts to move?

Chris B.

 

[Crofter]

Have had new bar that had groove really filled with paint, enough so that chain was binding. Make sure that chain is not .058 and bar .050. Check chain brake band binding as suggested and make sure clutch is not slipping. Chain should be free to pull around bar by hand. Make sure exhaust opening deflector is not bent and putting the exhaust down onto chain. We will assume you have the chain on the right direction, so we won't go there! LOL! Let us know what you find.

Frank

 

[stihltech]

chain guage

Stihl 3/8 is normally .050. 325 is .063.

 

[glens]

Thanks for the clarification, Stihltech.  It saves me from having to say it and thereby look like I'm attacking Brian's integrity.

All the other stuff covered here sounds plausible, for sure, but one thing I haven't heard yet is that maybe there's just plain so much heat being generated by the lean-running, clogged-exhaust-system engine that it's using the bar as a quite good heat sink.  I know my 036 20" bar gets a little warm to the touch too, even though everything else is in perfect to good working order.

I've had a couple of recent Stihl bars need minor stomping right out of the box, so I'd also suggest holding a good straight edge against it and see how much light gets through, just to cover all bases.

If the cooling system is clean and free-flowing, and if you can grab and hold the bar with bare-skin fingers, even only for a short while, I wouldn't worry about it.

Glen

 

[Spencer]

Thank for the advice guys. I`ve ticked of most of the suggestions..that is..

The chain brake strap is not rubbing,
The clutch is not slipping
The exhaust pioints away from the chain,
The chain is tensioned fine - not too tight/loose,
The Chain/bar/rim sprocket all match - 3/8pitch/.063 gauge
though the rim sprocket has some wear i`ll replace this as its the 3rd chain on the same sprocket.


BTW I also have a 026, MS200T, + MS 180-small saw and dont encounter any problems with these..
I think if the sprocket dosent work the new bar must be warped?

Spencer

 

[cbfarmall]

Can you try a known good bar and chain on this saw? Maybe what's on the 026 or you might have a friend who'll help you out. You'll find out which way to head.

 

[Gypo Logger]

Hi Spencer, it is commonplace for the bar and chain to be so hot after cutting, that you cant touch the bar for a few minutes. This happens during hot temps, such as above 75. I have even seen the gas actually boil in the tank of a Husky.
Hope I am on the right track.
John