660 Clutch loosening ?

[Racerboy832]

A friend brought over his 1 year old 660. Motorspins but chain didn't. Tried to pull the sprocket and the E clip was locked on. We ground the clip off , pulled the sprocket and the clutch was loose. Tightened the clutch up, new clip and fired it up. Clutch backed off. Same deal. I found a clutch on one of the 2) donor saws he gave me. Installed it and seems to be ok. The clutch that came on the saw looks like it has engaging ramps, the donor clutch was the same old style. Why would it back the clutch off? I've never seen this. The saw was never taken apart before.

 

[albert]

If it is tightened properly, it shouldn't come loose. Running it without the bar and chain can make it loosen. Always install the bar and chain especially after clutch installation, and rev the saw aliitle and apply the brake.

 

[splitpost]

If its not torqued down to spec it will come loose ,a cracked spider or damaged threads will do the same

 

[Racerboy832]

I've never seen one loosen up this quick. It was one burp of the throttle and it was loose. I've seen guys spin these on with their fingers and they don't fall off. They are reverse thread so I assume they tighten themselves. I torqued this one pretty good. I was just curious if this was something someone has seen. The saw was less then a year old and the treeman has been doing this for 25yrs and never had one come off.

 

[tlandrum]

would also guess broken spider

 

[Racerboy832]

Well your guess was right. Spider was cracked in 3 spots. This looks like a new style of clutch with tapered ramps where the clutch paws touch each other.