<-=- Club Bevel Heaven -=->

While not specific to the clutch basket bearing questions, my question is clutch related:

I'm in the midst of replacing the clutch on my 1978 900SS (Ducati Elettrotecnica version) with the Surflex SC S1425 competition alloy clutch & springs and now have the pressure plate, plates, center hub, and outer clutch housing drums removed.

I noticed that the pressure plate has Surflex clutch fibre material bonded to the plate. Since this is a newbie installation for me, it seems counter-intuitive to install new clutch plates whilst retaining the old material bonded to the pressure plate.

Am I overlooking something with this installation?

Cheers,
Herb...

That end of the clutch pack is the last to wear. Usually the plates about 2 discs in are the ones that take the brunt of the abuse. Install it and don't look back, it'll be fine.

Herbg,
In my case the friction material on the pressure plate (although somewhat worn) seemed serviceable to me. I did not replace it. Actually I am not sure if new (NOS) pressure plates are available(?), and buying used parts puts you back in the same position. Then the only other option would be to find a reliable vendor to refurbish the pressure plate with new friction material. I tend to agree with wdietz186 ..... you should be OK reusing the pressure plate ; unless you have noticed extreme wear or other damage to the friction material or pressure plate overall.

Thanks for the clarification. The fiber looks a bit thin but no obvious scoring. Since replacing it is not an option, I will proceed with this one!

Thanks for your help!

Cheers,
Herb...

Did some digging around and found a heavy duty replacement pressure plate - with kevlar fiber - at Gowanloch Australia. Since I'm very picky about these things, I decided to order it so that all parts are new.

The new pressure plate is about twice as heavy as the stock piece so that there is no flex. Apparently, the stock pressure plate can flex enough to contribute to 1st gear slippage. We'll see how it works out!

Before I install the new pressure plate and Surflex clutch, I'm wondering about the merits of "pre-soaking" the clutch in oil before installation. I've read various opinions on this - both for and against - so looking for some consensus.

IMHO, I don't see much downside to pre-soaking the plates before installation since this is a wet clutch setup.

Cheers,
Herb...

Hi,
When I redid my clutch I pre-soaked the new friction plates. My thinking was like yours ....... since it is a wet clutch what can it hurt? I don't have a strong opinion however. I am curious though about any negative opinions that you heard WRT pre-soakimg. What might be the percieved down side? As for the pressure plate I do agree that the stock unit is a little flimsy .... especially with stronger springs. So, sounds like a good move to go with a heavier unit. You will have a mix of friction materials in the clutch now, but probably not an issue. Did Gowanloch have an opinion on this? Again just curious.

Happy riding....
Old905Duc

yes - pre soak you fiber plates in oil before installing.

What is the correct torque specification for the Clutch Drum Nut/Washer? Ian Falloon, in "Ducati Bevel Twins 1971-1986", on the bottom of Page 214 mentions that this nut comes loose frequently - so much so, that the factory increased torque assembly ratings in 1979.

My engine is a 1978 crossover model (late 1977 engine) and the torque recommendation is listed at 50.7 to 57.9 ft/lbs. But from 1979, the rating increases to 87-95 ft./lbs.

Does that mean the nut/washer combo in post-1979 engines are heavier - able to tolerate the higher torque specs? Or, is it the same nut/washer?
Anyway, interested in what torque spec I should be using for this engine.

Thanks,
Herb...

Hello Herbg,
I think that you post a good question. I followed my Ducati 860GT/GTS factory manual which called out a torque of 7Kgm (approx 50.6 pound feet).
This manual was for the early 860 models. I did notice however that the nut was loose when I disassembled the clutch for my upgrade, which is one more data point suggesting that this nut can come loose. As for possible part changes with a higher torque, I think that you can use the manuals index on Steve's site to research any change to the washer or nut P/N's or nominal dimensions. I would speculate that there is no change, but I have not done the research myself.

Good luck and happy riding!
Old905Duc

Upon further investigation, I notice that the tab washer no longer has the "tab". Then, upon glancing over to the crankshaft primary gear, I noticed the tab washer under the 36mm nut was also sheared. So, now ordering new replacements before I torque both nuts down to spec.

I'm adding 222 Loctite to the 30mm clutch drum nut and will torque it down to the high side of the specification (about 60 ft/lbs) unless I can get some consensus on going to the higher spec that Falloon is quoting in his book.

Cheers,
Herb...

I'd say go with the consensus. Your plan sounds good. In my case the tabs were not missing, although the clutch drum nut was loose. Wondering if the "tabs" are residing somewhere in the clutch cover area?

Happy riding!

Old905Duc

Sometimes, depending on the finish of the contact area of the nut, the lock tab will move with the nut tearing the tab out of the notch it sits in. I've taken to marking the washer and the location of the notch to check for movement after torquing. I also try to bend the tab 180 deg. from the location of the tab. It seems the nuts that were machined quickly have a spiral pattern on the contact face that will tend to grab the washer. I sand them a bit on a piece of plate glass to knock the sharp edges off.

So I've now got everything buttoned up and ready to sort out the bugs.

At the same time, I've been preoccupied with carb issues so have not actually had the bike on the road yet.

As previous posts noted, I installed a Surflex Modifica S1425 competition clutch, the kevlar heavy duty pressure plate, a Brancato extended clutch lever, new gearbox spring, along with new rods and balls.

Effectively, the whole bottom end was apart to replace these parts. Roughed everything in so that I can select neutral and move through the gears.

So, while sorting out my carb issues today, I thought I'd ride up my driveway to see if I could select 2nd gear. Instead, the bike stalled immediately once I put it into 1st gear from Neutral. And, yes, the clutch was pulled in.

I'm scratching my head but something obviously needs to be adjusted. Any ideas on where to start troubleshooting this?

Thanks,
Herb...

I had a similar problem with the extended clutch arm. Although the lever force is decreased it is accomplished by a reduced throw. So the pressure plate does not lift as far as with the stock lever. I modified the clutch lever at the handle bar to slightly increase the overall travel. This did help, but still the clutch never fully disengaged. My bike would not stall when clicking into 1st gear, but finding neutral at a stop was almost impossible. Once underway shifting was OK ......... just could not get full and clean disengagement. I finally went back to the original lever. It is a manly pull, but does
disengage fully. Maybe others have found a way to work around this. Another important point is to confirm that the pressure plate is lifting uniformly and is not tilting. I had to rotate springs to alternate positions to optimize the lift and eliminate the tilting.

Good luck working through this and happy riding!

Old905Duc

When adjusting the adjuster for all the rods etc on the clutch pressure plate, you want to turn the thing in as far as you can so that when you push in the actuator arm towards the center of the bike, you have only a couple mm gap between it and the sprocket cover. The smaller the gap the more throw you will get. If this is adjusted correctly then you should be able to easily find neutral or click into any gear etc assuming everything else is adjusted correctly.