620i.e Sport Clutch Slipping High RPM

[gixer620]

Hello all,

I have tried searching through the forums on the web since buying this little fun bag in April but can find people with same problem but never a conclusion on how it was sorted :-(

Anyway the story so far, collected bike gave it a good hand full to overtake got lots of revs and no traction to move forward bugger.#

Prob: - more so when hot (200+) but evident also from cold in the lower gears up to 3rd no evidence of slip will accelerate with no problem above 7-8K, once in 4th/ 5th then around 5-6K normally as I go to overtake something I get that lovely roar from the engine but a slow motion forward, this revs upward to 7K then catches up with itself.

So this is what I have done:

1. Bleed the hydralics - no real evidence of air or even bad fluid or too much or too little.
2. Dropped the oil & filter - removed the plates some signs of blueing on the steels, had the plate thickness and stack height checked by a Ducati dealer ( nice lads at Snells, Alton) all over height apparently.
3. New oil & filter Shell Advance fully synthetic by the book, also re-bleed the entire hydralics with Shell fluid.

Initial result no slip but not so long after as in less than 50 miles the good old slip returned and has been back ever since.

BTW the clutch is very light and I have to wind the adjuster screw on lever fully out to stop it slipping earlier.

Any help before I start to spend money on clutch springs etc,( any suggestions on springs appreciated).

Thanks

Ian

[antonye]

If I remember correctly, a load of us running with fully synth oil had the same problems in DD racing. We switched to using Shell semi-synth and the problem went. It seems that fully synth is just too good!

[gixer620]

Thanks for that have read many a post talking about the oil being the cause of the problem, I suppose it is not so bad to drop the oil back out and then replace with semi I actually have some Castrol GPS semi which I could use rather than spending more cash :-) On hols at the moment but will do my best to update with a conclusion if I get there.

[Chaz]

Wrong oil mate stick some semi in & the problem will be solved;)

[nelly]

tbh, the shell fully synth has never given me any slippage problems, castrol and slikolene are the usual culprits..
When you say the matter is improved by unscrewing the detent in the lever improves things, are you running stock or pattern/aftermarket levers? These are usually the biggest culprit. especially the cheap pattern levers.
Try cracking the bleed nipple on the slave cylinder after pumping the lever a few times. If fluid comes out at anything more than a dribble, you could have a problem with the clutch hydraulics pumping up.

[gixer620]

Stock lever as far as I could tell still have the araldite in it before I got to work on it in a vice.

Only thing not stock is the clutch master cylinder top cover has one from somewhere in the USA still has I assume the std rubber insert to stop the fluid sloshing around.

Once back in UK I will try the pump and bleed, if it does fire out then whats the next step in the diagnosis ?

Thanks for all comments guys more helpful than I received on other forums so far.

[skidlids]

From one of my previous posts and the outcome was it worked fine and I'm still using the same setup in my current DD bike

http://www.ducatisportingclub.com/showthread.php?t=35525

As for the 620 Class A bike, it suffered from a immense amount of clutch slip at Cadwell as well as a small oil leak from the oil prewssure switch..
Off came the clutch casing, the switch was replaced and then the clutch plates were removed. All looked like new, there was no discolouration of the steel plates and all the friction plates were in a very healthy condition.
So I resorted to the same method of curing the slip as I did with the 750s clutch. Out came two of the stand steel plates and 3 of the standard springs to be replaced with 916 bits which again consisted of one dished steel plate (spring plate) one 2mm steel plate and 3 of the shorter but stiffer clutch springs.
I'll know if its done the trick when I take it out in practice at Pembrey.

[gixer620]

I did find your post when I searched but I was then lost as too how I muster up all the parts to be able to do it.

The springs are cheap and easy, silly question but do you also need shorter bolts when you fit them ?

As for the 916 plates can you buy these separately from a dealer or is it a search fleabay for a some going begging ?

One question I had was can this be converted to a dry clutch style or is it really not worth the cost, also saw in the Haynes there were models with a kind of slipper clutch is this worth considering ?

I have yet to really get to grips with this little toy it feels like it is worth some effort to sort it out as when no slip it rides well all be it an Ugly duckling of the dukes.

[chris.p]

One question I had was can this be converted to a dry clutch style or is it really not worth the cost, also saw in the Haynes there were models with a kind of slipper clutch is this worth considering ?

.


I am sure Dunlop will be along shortly to chat about his conversion, his post regarding how it was done is here.

http://www.ducatisportingclub.com/showthread.php?t=82172&highlight=clutch+conversion


Chris:burn:

[skidlids]

The springs are cheap and easy, silly question but do you also need shorter bolts when you fit them ?


No you use the same bolts as the spring top hats tighten down onto the top of the posts protruding from the clutch drum


As for the 916 plates can you buy these separately from a dealer or is it a search fleabay for a some going begging ?


You can by dished and 2mm plates seperately from Ducati Dealers, but most used clutch packs on Ebay should also contain then

[gixer620]

OK, so back in the lovely weather UK :rolleyes:

Anyway now had a chance to try the clutch pump and open the bleed and to be honest no big bang of fluid just a steady flow once open I assume this is gravity rather than pressure still being applied ?

So unless there is something else to try I guess next is to drop the oil and replace with semi then ultimately move on to the plates /springs approach after that.

Thanks again for all the input

[Spjallen]

If you have tried the oil I would take the time to consider the clutch plates, both priction and plain plates. I had really bad slip on another bike and changing these sorted it out. However, I did use OEM plates and made sure the stack height was spot on. (which is loads of fun and means buying a new tool, which is always cool)