Hydraulic Clutch Fluid Issue

[Ron1000]

Originally Posted by Luddite

Don't write off the cylinder just yet!

I think the problem may be that it's still connected and the piston will have eased out a few millimetres making it difficult for you to screw the cap on.

Ideally, you should remove the slave completely but, if you don't want the extra hassle of bleeding, try this in situ first.

Try to push the piston back into the body as far as possible, (making sure your reservoir isn't going to overflow when you push the piston back in), and then try to refit the back plate.

If that fails, I'd definitely get in touch with Oberon.

Good luck!

I’ll have one last play about with it and completely remove it, I don’t mind bleeding it up again. Pretty easy. I’ll defo phone Oberon on Monday.

[Ron1000]

Originally Posted by Luddite

PS I don't think it matters at what position the pushrod sits as, without the slave, it's free to rotate at both ends. As long as the anti-rotation pin is engaged, it'll be ok.

That’s good to know.

I’m off for a blast…on the streety…was supposed to be predominantly using the evo this season too

[Luddite]

Originally Posted by Ron1000

…was supposed to be predominantly using the evo this season too

And I'm sure you will!

If you can't get it sorted straightaway, (if you have to send the slave back to Oberon for a refurb for example), I'm happy to lend you my OE slave to keep you on the road.

[Luddite]

Originally Posted by Ron1000

I’ll have one last play about with it and completely remove it, I don’t mind bleeding it up again. Pretty easy. I’ll defo phone Oberon on Monday.

PPS if you clamp the feed tube between the reservoir and master cylinder, that should minimise fluid loss and make it easier to bleed as you won't be refilling the whole system.

[Ron1000]

With it off this is as tight as i can get it. Suspect they use some sort of calibrated impact tool in the factory to drive it home.



You can see the two indents are still fairly far apart. I’ll leave it alone now until i speak to Oberon.

[Luddite]

Some progress at least!

Did you manage to push the piston back in at all?

[Mr Gazza]

I reckon they probably have a tool that looks a bit like a pushrod with a pin across it.

I also reckon you could get it tighter if you dunked the body in some boiling water and left the inner in a freezer for an hour or so.
I'd put some locktite on the thead as well if you're determined to persevere with that slave, but it would be good to find out what is unscrewing it first.

[Ron1000]

Just off the phone to oberon.

Very nice to deal with and very helpful, i’ve to send it back for inspection to check for manufacturing defects and stuff as a precaution…and also to check if it’s damaged from the chain in any way. They will fit a new aluminium inner part too.

As for a potential cause (if it’s not the slave cylinder) he’s saying potentially chain slap over time could maybe cause it to loose but other than that he can’t think of anything and even that is unlikely.

Sooooo I’m thinking I’ll send it back but might just buy a different brand. One that is fully round to eliminate the possibility of re-occurrence. I belive CNC Racing do one.

[Chriswilly]

Had a similar issue a while ago on the M900.

Clutch operating well - level seemed fine - no obvious leak.
Inspected the master cylinder and came across a small amount of fluid and VERY worn
master cylinder rubbers.
Replaced the rubbers on the master cylinder and away we went.

Not obvious at first because any fluid leaking would have been dispersed on riding.

[Darren69]

I'd check the pressure plate bearing isn't worn/seized; it looks like the pushrod might have been turning the slave inner.

[Ron1000]

How would i check for that?

[Luddite]

Originally Posted by Darren69

I'd check the pressure plate bearing isn't worn/seized; it looks like the pushrod might have been turning the slave inner.

Originally Posted by Ron1000

How would i check for that?

I don't think it's necessary, Ron. You've already established that the pushrod is not stuck and we have a wet clutch on the Evo, so it's unlikely that the bearing would have failed. If you wanted to access the clutch, it's not the 30 second job that it is on the dry clutch models, you'd have to remove the right side crankcase cover.

I fully expect your Oberon to come back perfect and I'd stick with it. There's a large proportion of Ducatis out there with Oberon slaves and, on the whole, they seem to be pretty reliable. I'd put the company Oberon in the same category as Evotech in that they produce well designed products backed up by good customer service. And of course they're UK based.

Anyway, if you need an OE slave to keep you on the road while the Oberon is being refurbed, my earlier offer stands.

[Ron1000]

Thanks Lud and thanks for the offer.

I’m going to leave it as is until they send it back…I’ve got my other two bikes to use so not a problem getting out and about.

And it’s probably best if I don’t look at the evo for awhile, I’m getting frustrated with it and losing confidence in it…I’m going to pop out to the shed, stick it on it’s stands and cover it over for awhile.

[Mr Gazza]

I wouldn't be able to sleep if were mine until I had looked at the pressure plate bearing, in fact I'd change it anyway, as I often do on my dry clutch.

The thing is that the rotational force on the pushrod is greatest when the lever is pulled in to disengage the clutch and that's when the bearing is under load. If it's doing it's job it will spin in the pressure plate while the rod does not rotate.
Any problems and the pressure plate will try and spin the rod. I believe that the clutch spins anti-clockwise when veiwed from the clutch side, so that would be the force to undo the slave inner.
Thoughts of engine vibration undoing the slave are nonsense, as are suggestions of the chain catching unless there is something very wrong in both departments.

Quite how you would test it under load is beyond me, I hardly dare suggest pushing on the rod with the engine running with the rod gripped in pliers perhaps. I doubt you could apply the same pressure as the slave in any case?

Maybe I would try and construct some sort of bridge that was bolted on using the slave bolts? You would only have to push the rod about 2mm to replicate the slave's action.

Another option for you might be to knock the anti-rotation pin out of the rod. It would then have the effect of spinning the piston in the slave (which the pin prevents), but as the early models had no pin anyway it would no worse than those.

[Darren69]

I'm with Gazza, I think it's most likely been spun by the pushrod when loaded and not anything else that I can think of. The pin was added to stop the pushrod spinning and drilling through the slave cylinder, which they can do.