Ducati.ms - The Ultimate Ducati Forum banner

1 - 4 of 4 Posts

·
Registered
Joined
·
3,642 Posts
Discussion Starter #1 (Edited)
"Honk", "Squeal", "Chatter", call it what you will. For any Ducati owner with a dry clutch, you will have a shitty feeling clutch at some time during your ownership. There are a number of reasons for this: dirty plates, "glazed" plates, worn-out plates; and sometimes the plates just need to be shuffled. Before you proceed check out Shazaam's thread in the HoW: http://www.ducati.ms/forums/showthread.php?t=73438

Fixing your shitty clutch is basic maintenance that can be accomplished by (pretty much) any owner.

Tools you'll need:
Metric Allen keys (3-5mm at least)
Measuring calipers (cheap ones work fine)
Brake cleaner
Shallow bucket (to clean parts)
Shop rags (paper towels are okay)
Basic screwdrivers
220 grit sandpaper
Flat plate mirror (one you don't plan to use later)

Begin by gaining access to your clutch. You may or may not have to remove bodywork to do this.

Remove the four 5mm Allen head bolts that secure your clutch cover. There are six total; the bolts at 8 o'clock and (nearest to) 12 o'clock stay in place.


Remove the six 4mm Allen bolts that secure the clutch springs and caps, then the pressure plate. If the push rod comes out with the pressure plate, don’t worry. You can use a deep 17-19mm and 12mm sockets as a slide hammer and bushing to separate the push-rod and pressure plate. It is preferable to reinstall the rod through the slave cylinder side of the engine.

Check the plate-to-basket clearance. If your gap is getting over 2mm, replace the clutch pack now, or soon. Wear on the basket is exponential as the gap increases.


Remove the clutch plates and keep them in order as they come out. Mine was arrange much like the SPS pack in Shazaam's write-up. It’s good to have a magnetic retriever for the steel (driven) plates; and a couple flat-tip screwdrivers, or Allen wrenches for the friction (drive) plates. Look for any oil leaks. If oil appears to be flinging from the center-outward, it’s possible the pushrod seal needs to be replaced. Oil pooling on the bottom of the case could indicate clutch case inner seal is leaking (not common). Your clutch will look something like this… the outer basket and in the center is the “drum” or “hub” (slipper clutch shown for photo purposes):


Measure the thickness of all the plates as they were installed or the “stack” so to speak. They should, collectively, measure 36-40mm. Clean all your plates with brake cleaner, or denatured alcohol. Inspect friction material for wear according to Shazaam’s write-up. Check the steel plates for warping, and scuff them using a “random orbit” circular motion on a sheet of 220 grit sandpaper layer upon a mirror (the mirror is used as a flat surface). It’s good to scuff them to get rid of any “glaze” and also to look for warping. Warped plates will not scuff evenly. Check for any excessive bluing… it’s normal on the splines of the plate, but any blue plates and chances are the plates are cooked.


Separate your plates by type and relative thickness. Shown below are eight 1.5mm sintered plates (left) and a 3mm Barnett organic material plate:


Below are the different steels. In this pack, I had four 2mm plates, three 1.5mm plates and two 1.5mm “convex” plates. The convex plates are indicated by a dot stamped into a spline; their purpose is to make the engagement more progressive, or smoother.



My stack measured out to 37.8mm, and all the plates were serviceable, even the nasty-looking steels. I still had shitty engagement, so it’s time to shuffle ‘em up.

NOTE! : While most of this info applies to all Ducati dry clutches, standard clutches begin the stack with one or two steel plates; where as SLIPPER CLUTCHES begin innermost with a FRICTION plate. If a steel plate is innermost on a slipper clutch, it may drop off the hub and lock-up the clutch when the slipper engages. ALWAYS end with a steel plate on the pressure plate.

I split the groupings of plates into “stages” separated by the convex plates. I’ve used this method with very good results compared to the OE arrangement. Also, I replaced the innermost sintered plate with the Barnett plate – the reason for this was to minimize wear on the hub where the friction plate rides on the flange (this pertains to slipper clutches only!) Friction plates will always be separated by a steel plate. This is my example of how I rearanged the stack in stages. Note how the convex plates and steel plates are distibuted evenly :

Inboard

Barnett (3mm) Friction #1
2mm
Friction #2
1.5
Friction #3
1.5mm Convex
Friction #4
2mm
Friction #5
1.5mm
Friction #6
1.5mm Convex
Friction #7
2mm
Friction #8
1.5mm steel (shim
Pressure plate

Since I replaced a 1.5mm Sintered plate with the 3mm Barnett plate, I had to remove a 2mm flat and then “shim” the stack with the last steel plate to maintain stack height (keep old steels for shims). If your clutch was slipping, and your stack is less than 36mm, add an additional steel plate shim, or two to make up the difference


After the plates have been arranged and reinstalled, replace the pressure plate (grease the end of the push-rod and anti-sieze the spring bolts), tighten the springs down in alternating stages to keep the tension even on the plate, don't over-torque the spring bolts! Reinstall your clutch cover and bodywork, if necessary. Go for a ride and enjoy!
 

·
Super Senior Poster
Joined
·
6,328 Posts
Great stuff Bella! Thanks for taking the time to post the pics and captions. I have a Barnett clutch pack from DesmoTimes. I just cleaned it up and put it back together, wave disk in the center, the rest of the deck I just shuffled. It does help the feel after you clean the dirt, dust off the plates.
 

·
Registered
Joined
·
3,642 Posts
Discussion Starter #4
Some additional notes...

The purpose behind shuffling the plates two-fold: First, is to re-distribute the wear of the plates more evenly. Second, it's been my experience that the OE stack order is not always smoothest. If you notice in Shazaam's thread, Ducati recommend the convex plate be positioned on the end(s) of the stack. I've found that when the convex plate(s) are distributed toward the center, engagement is smoother. Sometimes you have to experiment with the position of the plates; if it works, roll with it.

Reiterate: keep a few old plates of varied thickness for spares and shims; especially the convex plates, they are hard to come by.

Replacement clutch packs, OE or aftermarket, come in different configuarations. Sometime, when you order a clutch, you don't know what you're getting. Dont worry if the replacement pack is different from what came out as long as the stack height is within spec (36~40mm). It's been my experience that OEM and Surflex offer the best feel. Barnett is the least expensive, but the feel has suffered since they changed to the new red-colored material (circa 2005-ish).

Some racing/slipper packs come with very thin 1mm steel plates to accommodate an additional friction plate... I have not been able to get one of those packs to work smoothly. Generally, the thicker steels will have less chatter.

The dot on the convex plate goes OUTWARD, for proper orientation. Two convex plates in the stack are usually smoother than one, or none. You can substitute a convex plate for a flat plate, just maintain stack height within spec.

Don't neglect your clutch springs. Check that the free length is proper spec (may vary) for each; and try to arrange them so the springs distribute force evenly to the pressure plate, i.e. shuffle the springs too. It's a good idea to keep some old springs for spares.
 
1 - 4 of 4 Posts
Top