[piercems3]

I was able to get the bike out of the garage for the first time this spring. Most of the work I did on the bike during the winter was cosmetic restoration, with the only motor work being valve adjustment and new belts. The motorcycle only has 3800 miles, and the clutch felt perfect last fall when I purchased it. I only had the bike long enough to put about 800 miles on it, but it did not slip at all.

The only thing that I did related to the clutch was when I replaced the fluid and bleed out the system. The clutch feel is great and disengagement is good.

It only slips at WOT above 7500 rpm. I plan on pulling the cover when I get home from work and inspecting, but does anyone have any ideas why it would be slipping or what might have happened while it was stored in the garage this winter? I am not sure if it has anything to do with it, but it was only about 45 degrees F on the ride.

Thanks for the help!

 

[nlzmo400r]

No point in over thinking this.

1.Make sure the clutch master cylinder is allowing relief of pressure back into the reservoir and not pressurizing the clutch slave cylinder causing it to slip.
2.Check clutch plate condition and stack height.
3.Check for oil leaks behind the clutch basket that could be contaminating the clutch discs.

 

[piercems3]

Thanks for the advice! What is the best method to verify the relief of back pressure?

 

[Strega]

Thanks for the advice! What is the best method to verify the relief of back pressure?

The clutch lever should have some free play before you feel resistance at the lever. This allows fluid to expand and return to the reservoir.

The standard test for detecting worn-out clutch plate friction material is to check for slippage when accelerating WOT in top gear. Some people are just harder on clutches than others, so service mileage will vary over a wide range.

You can often stop slippage by maintaining the force pushing the plates together. The idea here is to maintain the 38 mm new stack height as the friction material wears off and reduces the thickness of each plate. The higher the stack height, the more the springs are shortened/compressed, and the greater the force pushing the plates together. The clutch slips when there's not enough force supplied by the springs or the friction material is worn completely off.

The service limit on 3 mm friction plates is 2.8 mm. For 2.5 mm plates the service limit is 2.3 mm.

The plain metal plates come in stock 2.5 mm or 3 mm thicknesses. When the overall plate stack height wears 0.5 mm, replace one 2.5 mm flat plate with a 3 mm one. At 1 mm stack height wear, repeat for a second flat plate. At 1.4 mm - 1.6 mm wear, replace all the friction plates. Allowable friction plate wear is 0.2 mm (each).

Ducati considers both the plates and clutch basket to be wear items. By the time you need to replace the worn-out clutch plates the basket has been notched from the impact loads of the plates. Ducati specifies the allowable gap between the plates and basket as a quite small 0.6 mm, effectively saying to replace the basket and plates together.

Also check the pressure plate throwout bearing and pushrod for smooth rotation.

 

[piercems3]

Thank you Strega for the great information. I didn't have time for a full tear down last night, but I pulled the cover off and blew out the dust. There wasn't much dust and the basket didn't have any significant notching yet. Clutch actuation seemed smooth, but I don't think there is enough play before it has resistance at the lever. After inspection, I gave it another WOT blast and it didn't slip.

I think I will look at adjusting the actuation point on the lever. It is possible that as things heated up they have even less play.

 

[Strega]

I think I will look at adjusting the actuation point on the lever. It is possible that as things heated up they have even less play.

If the master cylinder and levers are stock, then I caution you against trying to adjust the lever free play. This is adjusted at the factory by Brembo and needs no further adjustment.

You can determine if the tiny compensating port (on the left in the illustration below) in the master cylinder is blocked — or covered by a misadjusted piston — by opening the reservoir cover and checking to see if there is surface movement of the reservoir fluid during the free play portion of the lever pull. You should see a little squirt of fluid before you feel resistance at the lever.

Also see:

http://www.ducati.ms/forums/80-hall...master-cylinder-adjustment-2.html#post5824849