Can anyone tell me if this is normal? I was tuning the saw last night and the clutch cover got pretty hot. The needle bearing and springs look fine?
Looks like some heat discoloration on the clutch as if the chain was really tight or binding but I imagine you already looked into that. Strange indeed. The cover could be from the muffler.
The clutch cover is from the exhaust and I cannot imagine getting the spider hot enough for it to turn blue 700° if I recall. My bet is when it was heat treated.
The clutch itself is not even close to where that discoloration is located. Like others have mentioned it is the exhaust causing it.
Had a similar problem with my 260, exhaust got so hot it melted some of the top cover. Put in new fuel line, fuel filter, and an exhaust cooling plate. No heat problems since.
That will help make it run cooler not hotter. If the exhaust exit is toward that clutch cover some it may be blowing on the cover. No big deal.
I have done a bunch of muffler mods because they make the saw run cooler. It is when you start porting and bumping up the compression, advancing the timing that starts to make them run hotter. But a other wise stock saw with a muffler mod is good for it even though it will become louder. There is a lot of designs that go into a saw because of EPA regulations and not all of those make the saw run better.
Your first picture shows black discoloration around the top of the brake strap. Does your brake work ok? Does the chain move freely when the brake is released? When you are cutting does the chain stop moving even when you are at wide open throttle (hogging into the cut too much and stopping the chain)? If the clutch is slipping a lot it could build up some heat on the clutch drum. Is the clutch drum (not pictured) discolored from heat? Is the bar accepting the oil from the chain oiler pump or building up around the clutch / brake area? Do you keep your chains sharp all the time? Are the depth guages (rakers) set properly? Sorry for what seems like silly questions, but if the brake is dragging or clutch is slipping there could be excess heat building in the clutch area. The black plastic in the second picture looks exhaust related like others mentioned. My first muffler mod I had directed the exhaust gasses forward and down from the muffler and when bucking large logs, the hot gasses would get trapped and pushed on the oil tank just below the muffler to the point it was melting / burning the surface plastic there. I changed that real quick to get the gasses away from anything that they could harm. I hadn't thought of when the power head was up against a 30" log... Lesson learned...
That black discoloring was already there after I bought the saw. Chain brake works. Saw oils fine. Chain is sharp. Drum doesn’t appear to be discolored? Chain moves freely. The only thing I’ve noticed is the saw bogging when In a cut at times but I assumed that was maybe too rich a setting on the high carb?
That clutch cover is made from magnesium not plastic and the discoloration is on the outside of the cover and not from the inside out by turning hot.
To me, the melted plastic around the brake band is troubling. Why only 10-2 o'c? If previous owner pizz revved with brake on - you'd think more generalized melting. 1st pic - If the brake is OFF, I don't see enough room between clutch and band for the drum sprocket to get in there and move freely. Maybe I'm wrong and it's just close tolerances on the 260.
