First impressions after recently fitting a different engine which included a STM slipper clutch to my 748 are that I am feeling a kick back or pulse through the clutch leaver and a loud clunk when changing down, if I blip the throttle open enough I can avoid this happening. Is this normal.Changing up is the same as a normal clutch. Steve
I've just had bikes with slipper clutches fitted as standard. I've never experienced anything like that.
Thanks ET, I know there are different types of slipper and wonder whether it is something to do with the ball and ramp design of the STM. Perhaps one of the racers or Nelly will be along soon. Steve
I have an stm evolution slipper clutch and I have always had a click through the lever I think this is normal to stm slipper clutches. The loud clunk when changing down however isnt normal . Slipper clutches need quite a bit of maintenance and the stack height needs to be correct. Ramps need greasing etc. I often shuffle my plates around when I take it apart for cleaning . It sounds as though yours isnt quite disengaging fully . shuffle them round a bit but make sure you start with a friction plate and have at least 2 concave steel plates in there.
the STM evoluzione uses a spider spring that are known to break with use <http://motowheels.com/i-6921093-stm-slipper-clutch-springs-spider.html> if its broken, the clutch wont slip and work basically like a dry clutch
if its a 48tooth you will need special tool to get off <http://www.ebay.co.uk/itm/DUCATI-DRY-CLUTCH-TOOL-WORKS-WITH-OEM-AND-T48-BASKET-STM-/281056885589?pt=Motorcycles_Parts_Accessories&hash=item41704bbb55> the STM workshop tools are silly money
I have broke the spider spring on my sigma ballan ramp a few times. It results in the clutch slipping like mad. check the spider spring, the condition of the ramps and balls etc. I use a tiny bit of moly grease on the ramps to aid the balls moving. dont try and push the bike , thats how I brake spider springs.
I think it's the basic model, just had the plates out but cant undo the center nut, ( just ordered a holding tool from machine mart) all looks ok from what I've seen so far. Thanks for the replies so far. Steve
Not unusual tbh. It's the drum settling back down against the drive faces on the back plate. Could be a weak or broken spider spring, could be due a service but I wouldn't worry over it unless its slipping or it's not releasing properly when you ask it to. The ball and ramp type tend to do it more than the plain ramp type? The slipper in my 748 has always tended to do it when pushed and its worked fine for a good few years now.
