i have a sigma slipper and accossato slave. i cannot seem to feather the clutch so 1st gear is very grabby which is both annoying and also slightly embarassing when being waved onto track by grumpy marshalls with my almost kangarooing from a standstill fluid changed very recently and so what do i do - bleed clutch - ?
Beware. If @Nelson says to grease and bake your clutch plates, the consequences are a smoke cloud eminating from your cooker that will betray your location from space.
Archetypal for a ramp based, dry slipper clutch. Cleanliness is essential as is the very sparingly applied lubrication of the ramps that release the compression of the plates. I use (well that’s used to use now) generic articulated lorry, 5th wheel grease but any high temperature grease that doesn’t go runny under strain should do, vary sparingly applied ……. I’ll state that again, very sparingly applied. Andy
It is usual for the clutch pack to contain a single 1.5mm dished steel plate which is denoted by a peening mark. It was also very common to experiment with 2 dished plates, inserted mirror image either side of a friction plate, that often helped with what you are experiencing. IIRC, the ‘ideal’ total pack thickness is 36.5mm and it depends on whether you are using ceramic friction plates or organic friction plates. If your Sigma clutch basket is anodised aluminium, I’d recommend aluminium backed organic friction plates which will help with the life of your clutch basket. If your Sigma basket is steel however, I found the steel backed, ceramic friction plates (which are thinner and you use more of them) was a more reliable and longer lived. Steel compression plates come in 1mm, 1.5 (dished) and 2mm thicknesses. I often ran 2 steel compression plates together as the last plates in the stack to help adjust the stack height. A caveat to all this, it could be a load of bollocks if the Sigma clutch is substantially different to the Bucci style which most clones copied. I’ve never used a Sigma which was marketed by Neil Spalding. There’s a bit of useless trivia Andy
You will need to remove the hub to get to the ramps/balls. Basic gist is to ensure all cleaned, then lightly greased. Followed by careful plate assembly. If anything is badly worn replace it.
The friction discs don't have to be baked in an oven after being smeared with white lithium grease, a hot airgun played over the discs works just as well.
I’m wondering if I can do this with my Sigma 48t clutch, as it’s tricky to get it going from a stand still sometimes. Once moving it’s fine. @RC1 is yours the 12 tooth or 48 tooth version? I don’t want to screwup the clutch pack as they are quite spendy to replace. Also, if yours is the 48t model, any chance you could send me the install pdf that comes on cd. I seem to have mislaid mine!!! thanks in advance Deaks
It works!!!! Pulled the clutch apart this evening and did the spray on wipe off method using wd-40 white lithium grease. Took it out for a blast with a good mix of stop start traffic and ragging it up through the gears. Smooth on take off and no slipping under full load. Happy days, I was getting close to changing to a different slipper!!!! £9.42 very well spent
