Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 998 / 996 / 916 / 748 > slipper clutch / slipping

[Bungi]

ive fitted a second had (seems pretty good knick) slipper clutch to my track bike, its a ball and ramp type.

not hundred percent sure ive got it all together right especially the plates?

so what i did was (after getting the std clutch off) took off the collered spacer with the oring in and changed that as it was a differant depth.
then placed a washer thing on the shaft and then the clutch then the spider spring thingy then the retaining nut. ok so far i think.

now the plates
normally i belive one should fit a metal plate but such is the case with slipper clutches i understand this is not so, ( as they can pop themselve behind the centre)
so fibre plate metal plate all the way through till im almost out of space & finish with 2 metal plates before the centre plate.

SO IS THIS RIGHT? coz it slips a bit at high revs.

i could squeeze another fibre plate between the last 2 metal ones but then the clutch lever will only pull in half way at the handle bars. (so i didnt try runing it like this)

i assume that i cant run a fibre plate next to the pressure plate??? being alloy?

all the fibre plates seem to have plenty of meat on them by the way.

i was wondering if im missing something like has the differant spacer meant that i need a different push rod?

any ideas peeps?

[Gizmo]

I've spent the last 2 weeks taking my S/H slipper and apart and putting it back together to try and stop the thing slipping when it shouldn't

your first plate should be a friction, if you look at the centre drum back plate you'll see it actually has a steel plate held on by 8 bolts so go friction, steel friction until you build it up to between 4 and 5 mm at the end. the first steel in should be a convex plate with the dot facing outwards, the last steel touching a friction should also be a convex but with dot facing centre. Number of plates varies according to friction plate thickness, some only have thinner 2.3mm plates, some 3mm and you can get 1.5mm and 2mm steels so there isn't an exact order that will wokr for everythign. i added an article to the upnorth tech library on this. Most important thing is to get the pack to between 4 and 5mm off the end that should allow the pushrod to open the pack and not slip if its isn't pushing out it sounds like you have too much preload on springs and plate can't go out far enough cos spring coil binds or bolt cap is too far in.

If its slipping at high revs its more than likely the plates worn as if springs are coil bound you must have a reasonable amount of pressure on the plate and pack, if you took a plate out to get lever to move it might be you haven't got enough pressure on so thats why it slips check the pack is between 4 and 5 mm off end.

it Took me a while to work out how the slipper worksbut think i understand it now but I need to mess around with the tolerances on the plates and where the pressure plate sits, the spider spring controls slip at launch but by moving pressure plate away from the centre drum it should be possible to alter the point the centre drum pushes the plate and opens pack by adding an extra steel plate, might hit same problem you have with springs and caps then though

[Bungi]

Originally Posted by Gizmo

If its slipping at high revs its more than likely the plates worn as if springs are coil bound you must have a reasonable amount of pressure on the plate and pack, if you took a plate out to get lever to move it might be you haven't got enough pressure on so thats why it slips check the pack is between 4 and 5 mm off end.

where do you mean by taking measurement "off end"
is this off edge of basket of centre of hub?
sorry i dont mean to appear thick!! please explain

[Gizmo]

Originally Posted by Bungi

where do you mean by taking measurement "off end"
is this off edge of basket of centre of hub?
sorry i dont mean to appear thick!! please explain

i take mine off the centre drum, the plates rest against the backing plate attached to it and build up from there and the slipper releases by the action of the centre drum pushing against the inside of the pressure plate. you can measure maximum "lift" by the distance from centre drum flat to the end of the shaft on the backing plate it slides on without the spring in place, the distance from edge of presure plate where it sits against pack to the inside diameter the drum pushes is 7mm. by altering pack with 1.5 and 2 mm plates it might be possible to reduce this distance and get the plate away from drum so if your spring weakens the first bit of drum movement don't release pressure, it might need small washers under the caps or different spring caps, i've got 3 sets of caps and each is a different height so alters preload pressure. Same thing with springs, some seem to be thicker coils and bind more easily, they seem to need a taller cap.

TBH the basket should have little to do with it other than retaining the friction plate tangs. Saying that mines still slipping but i'm waiting for new plates arriving.......

[razz]

You're better off measuring the the distance between the pressure plate and the drum centre with the clutch fully assembled. That way all of the plates are compressed (including the dished steel ones) and you get a truer picture. Does your pressure plate have holes in it so that you can see the centre with the clutch assembled? If so, measure the depth through one of the holes to the clutch centre, then subtract the thickness of the pressure plate at the hole. Neil Spalding @ Sigma recommended a gap of 1 to 1.5 mm (in other words the clutch centre has to rise up the ramps between 1 and 1.5 mm before it starts to push against the pressure plate and make the clutch slip).

[Bungi]

this is all a bit higher tech than im used to (never had a slipper clutch b4) will try and take a look and see what i can apply from your advice, thanks guys.
will let you know how i get on

[Jon]

You should examine your steel plates also. They should be totally smooth, any scoring and they should be discarded. Because you say it s/h, I would change the friction plates as you do not know the full history of them. The doner bike could have been raced or spent many an hour on trackdays. If they are your own std plates with X amount of miles on them, treat yourself to a nice set of carbon plates.

[Gizmo]

Originally Posted by razz

Neil Spalding @ Sigma recommended a gap of 1 to 1.5 mm (in other words the clutch centre has to rise up the ramps between 1 and 1.5 mm before it starts to push against the pressure plate and make the clutch slip).

thanks for that, i'd thought it was 2 to 3mm between drum and plate if you use the 4- 5mm from end everyone suggests. might see if i can measure it internally

[Bungi]

so clutches run with 8 friction plates,

q is it ok to run it with 9 as they seem to fit in?

or does this mean oops ive got something wrong

[Gizmo]

Originally Posted by Bungi

so clutches run with 8 friction plates,

q is it ok to run it with 9 as they seem to fit in?

or does this mean oops ive got something wrong

i think the RS version runs 9..... as ong as you have the 4 - 5mm play i can't see why not but i'm sure someone who really knows will be along shortly.......