Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 998 / 996 / 916 / 748 > JHP clutch slave cyl

[final_edition]

I have fitted a JHP clutch slave cyl to my '04 998s and I am having a few problems with it.
What I've noticed is that it is hard to get into neutral, when stopping at lights etc. When changing down, the gears feel notchy as if the clutch isn't fully dis-engaging. If I have the bike on the paddock-stand and select 1st gear while the engine is running, when I pull the lever in the back wheel still spins and will only stop with the back brake applied. If the brake is released the wheel will spin again.
I've read other threads with regard to rod length (oeer missus) but I thought having a later bike mine should be ok.
I've bled the system correctly.
Any ideas?
FE

[dave996]

The push rod for the clutch will be fine, if it was too short then you would be able to engage the clutch at all.

Not too much help, sorry.

[final_edition]

It seems as if the piston isn't travelling far enough to fully dis-engage the clutch.

[Jools]

Any Ideas?

Yes...All of these aftermarket slave cylinders work to make the clutch pull lighter by having a bigger bore. Your master cylinder, however, is still the same size it always was and, therefore, will still only pump the same amount of fluid. This means that because the slave cylinder now has a bigger bore it will now have a shorter stroke for the given volume your master cylinder can pump - therefore it won't push the plates as far apart and therefore they may drag.

It is a question of bleeding I'm afraid, all these aftermarket jobbies are VERY sensitive to the merest bubble of air and sometimes (as was the case with the standard master cylinder on my ST trying to push an STM slave) the master cylinder is just too small - KeefyB fitted it to his 999, which has a bigger volume master, with no hassle.

You just need to keep bleeding I'm afraid.

[butch890]

Sounds like a longer rod is needed
Butch

[chicken]

Is this the lighter clutch action slave? if so, the throw will be shorter (it's the trade-off for having a wider bore).

The wheel will probably still turn if you are in first gear and it is on a paddock stand with the wheel in the air. Does the bike want to move forward when the wheel is on the ground with you sat on the bike?

I don't know about the superbikes but my STM slave for the SS came with a small insert that takes up the initial part of the slack - it may be that you need one of these?

[final_edition]

It is the lighter action one.
The bike will not creep when in gear with the clutch pulled in. I have bled correctly and even had a cable tie on the lever overnight.
I can physically see that the pressure plate doesn't travel as far with the new cyl as it did with the old one.
How can i measure what size of spacing rod I will need?
Maybe a call to JHP tomorrow is needed.

[Jools]

Chi, you only needed the spacer because your bike was pre 2001 when all the bikes had shorter actuator rods. The aftermarket cylinders all need the longer rod of the post 2001 models, which of course an '04 998 is.

So FE, you already have the longer rod. Think about what a spacer will do...all that will happen if you put in a longer rod or spacer is that when you let the clutch lever out the clutch springs will push the actuator rod back towards the slave side of the bike as far as it needs for the clutch to engage. All you'll be doing in effect is to move the starting position of the piston further towards the end of the cylinder - I tried this with the STM and only succeeded in packing the slave out so far that the piston was pushed back further than the cylinder inlet and wouldn't move at all. You'll get more shove on the very first stroke of the lever but then the pressure will equalise, the starting position of the slave piston will just move back resulting in nothing more than a bit more fluid being pumped back into the reservoir.

You may think that you've bled it properly, but very often these things need to be vacuum or pressure bled.

[final_edition]

I will try pessure bleeding it, if all fails an up-rated master cyl is on the cards.

[Rob B]

try knocking it in to nuetral as you roll to a halt. It'll be easier than when you are stationar with one half of the geartrain static