Clutch Help!!!

[codywood806]

Hey everyone,

I am new to the forum and am looking for some much needed help. I recently changed the clutch on my 1998 Ducati Monster 750 and am having issues with it not completely disengaging. The bike has 33,000 miles and the original clutch was going out. I replaced the OE clutch with a Barnett Kevlar unit, part #306-25-10001. I pre-soaked in motor oil for a couple hours prior to install. The install went smoothly and I made sure to align the notch on the clutch basket and clutch plate. Torqued the clutch springs to 5 ft-lbs and buttoned it back up. At first the clutch was working perfectly and everything seemed great. Then as the bike warmed up the clutch wasn't disengaging completely to the point where I couldn't get neutral at a dead stop. Today, I pulled back off the case cover and inspected to make sure I had put everything in properly. The pressure plate is coming off contact with the clutch disks but now the clutch pressure plate/basket will not skin freely when it is disengaged like before. I took a video of me trying to spin the basket and you can see just how hard it is. Is there a possibility that the clutch disks are sticking together because of the pre-soaking? Any suggestions/help would be awesome.

Here is the video of me spinning the pressure plate and showing that it comes off contact with the clutch disks.
https://drive.google.com/file/d/1_HXVWRuMN9kh9Uw74iFg5K6XTBpFWI-2/view?usp=sharing

Thank you, Cody.

[Howie]

Stack height needs to be checked and corrected.  Better yet, get OEM clutch disks, IMO, they work best on wet clutch Ducs.

[koko64]

+1 on Howies suggestion. What weight oil you using?

[codywood806]

Alright, I just got done tearing it all back apart and here is what I got...

1. I am using Mobil 1 20W-50 "V-Twin oil"
2. The clutch stack is about 1-3/4" the best measuring device that I have is a measuring tape need to get a set of calipers.
3. The disk order is as follows, starting with the inside disk that is pressed against the clutch basket: F - D - F - D - F - D - F - D - F - D - F - D - F - D - F - D - F
    (F) = Friction Disks [9]
    (D) = Disks [8]
    Total Disks [17]

Finally, when I went to pull the stack all of the disks where stuck together. I had to manually separate them and it was quite difficult. It was a suction effect.

How wet should a "wet clutch" be? I mean these were pretty soaked from the oil bath prior to install. Should I give them a wipe down and call it good or is something blatantly wrong with the specs that I listed above?

[koko64]

Just checking something. Friction plates have the brake lining material with outside tabs and the Driven or plain plates are the plain steel plates.
I think Motul 10/40 would work better with a wet clutch.

[ducpainter]

Pre-soaking wet discs is the correct method to ensure they don't burn up before they can get wet.

20/50 is what I used in my 750 when I had it. I had no issues with OEM discs. Mobil 1 V-Twin wouldn't be my choice, but it should work.

I'd try bleeding the slave, and if that doesn't work, I'd be looking for an OEM clutch pack. The Barnett clutches don't seem to work well in Ducs.

[koko64]

The stack looks right according to the manual (kind of opposite to dry clutch plate order). These clutches are sensitive to oil type. The clutch is dragging not slipping?
Its true that Barnett wet clutch packs don't have as good a record here as their dry clutch kits. Before buying a new clutch pack consider changing oil brand andh viscosity.
If its dragging and not slipping I would try Motul 10/40 Moto oil. If it doesn't work you can drain the oil into a clean container and keep it for next time.

[ducpainter]

It isn't oil weight...maybe type, but not weight. 20/50 synthetic works fine in wet clutches, and in '98 that is the weight oil that Ducati recommended due to the type of cam bearings. The rec was changed when they switched to plain bearing heads.

The fact that it worked fine cold, but not hot, is a clue here.

[koko64]

True. I get it. I run 20/50 or 15/50 in my 900.
The 10/40 Penrite in my 750 drags until its real hot and worse wigh 15/50-20/50 (stock plates on 19,000 miles). The Motul changes slick, so its also additives, etc. Cody has the opposite going on which may be due to the thermal effect on plate expansion or friction material which implicates the Barnett design. I'm giving him an option due to the possibility of oil incompatibility with the finnicky Barnett wet plates as a last ditch effort before buying new plates.
Stack height should be 41.3 according to the Haynes manual for '98 on wet clutch models. 1 3/4 " is about 44.45mm.

[ducpainter]

His dragged hot, not cold. Kind of opposite from the typical oil issue...no?

I'm not discounting the effects of oil type. I just think there's something additional going on here.

[koko64]

Yep for sure.
Will be interesting to see what the stack height can be set to using some of the old packs driven plates.

[Howie]

Normal wet clutch behavior is to drag a bit cold.  In a few blocks drag was gone in all but weather too cold for most riders.  I noticed no difference in drag between 20W-50 and The reverse is happening here.  Drag when hot makes me think the friction material is at fault.  I sold my old 750 about three years ago with over 80K on the original clutch.  Our club president had over 100K on his original plates.  The new owner is still running with those plates, no problems.

Yeah, I would not be anxious the throw out those plates I paid good money and dip into my pocket and by OEM.

Long shot;  Inspect slave for leakage and bleed.  Desperation;  Measure stack height hot and correct to 41.3 mm.

 

[codywood806]

Wow, thank you everyone for those insightful responses.

Just to clarify with everyone, when I first installed the clutch it worked great (no dragging at all) until it got hot. NOW it drags mildly when cold (enough to push bike forward when in gear) and drags so mush when hot that I can't get the bike into neutral.

The first thing I checked was my clutch slave and master cylinder. I took off the slave and it was completely bone dry and then I flushed and bled the entire system.

I think my best and cheapest course of action would be to pick up a set of calipers after work today so I can give you all a definitive answer on the stack height. Unfortunately, I threw out the old stack after I originally tested the clutch (before warming it up)... Dumbass.... Do I have any options to adjust stack height if it is off or am I just SOL?

Thank you again for all the great replies, Cody.

[Speeddog]

Take that Barnett stack out, and try to get your cash back.

The OEM stuff is super reliable in normal use.
Get a good used OEM pack and call it a day.

[koko64]

Do you blokes think it's a thermal issue with these Barnett plates, a chemical issue of their linings in oil or just a wrong stack height Barnett have settled with?