Clutch not working properly

Hi, got a problem with the clutch. If I pull it in quick the clutch works ok but if I pull the lever slowly with little pressure it will go all the way back to the bars without activating the clutch. I'm thinking master cylinder seals gone but has anyone else had this problem before I start spending money.

Without actually giving it a grope I'd say you are spot on.

How many times in its life has it had it's clutch fluid bled? What year bike? Sadly, and for some reason we've never managed to work, CARC bikes are murder on clutch fluid. If you bleed it clean within a few weeks it'll be black as coal!

We bleed all hydraulics every 10,000km service or yearly. Is that overkill? Well, it seems to save the seals on the bikes we do regularly. (Shrug?)

The original master cylinders are still available but are poisonously expensive. The clutch master on my Tenni beast is dodgy at best, (Although since bleeding several times it seems *Better* but not right/perfect.) I'm seriously considering going to radial masters on the yellow bike and transferring the clutch master over to the Tenni. Problem is I hate those 'Piss cup' reservoirs the radials usually use and while I know that *Solid Mount* ones are available because Mark has them I can't remember their actual cost as it was so absurdly astronomical that I fainted when he told me and had to spend three months in therapy to cope! I seem to remember something like €400+ was the figure quoted!

€420 a pair plus shipping.


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Wouldn't it be better to get a seal kit?

Well yes, it would.

BUT.......

I bought one off the innerneck and it's incorrect.

Brembo don't market a kit for the MC used on the CARC bikes specifically but I'm hoping I can find a cross reference.

Often the problem isn't actually the seals, it's the bore of the MC. Now if you're lucky you can sleeve it but if you can't then a new MC is the only choice.

Fully agree with Pete's diagnosis, mine did exactly the same. Luckily I scored a known, good 2nd hand unit.

I think the reason that the clutch fluid goes black (and that the standard clutch reservoirs corrode really quickly) is that the rubber boot in the clutch reservoir does not expand as the fluid moves - it gets sucked in and leaks air and water inwards and a bit of brake fluid outwards.

If you look at the boot in the brake reservoir it is the normal sort that is folded so it can expand as the fluid goes down. the one in the clutch cylinder is not folded - it can't expand it just gets sucked in as the fluid goes down.

Well my one does and with the oberon cylinder at the bottom when i bleed it the lower fluid comes out clear then the darker fluid comes down from the reservoir.

My two pennorth

Thanks for the input guys. I'll have a think about my next move. Luckily I have other bike's so there's no rush.

No matter what, if you own a 8V, you're in to bleed the clutch fluid periodically like Pete says.
It's not hard so not a pain in the butt.
I bleed mine at every service intervals but I replace the fluid twice in between... I basically suck it out of the reservoir with a syringe (not completely) and top it up with new fluid.

Dammit. I bled the clutch, new Dot 4, rode around the block, all good. But while writing the note into the GRiSO’s journal, I noticed my handwritten note that last February, Desmoto (shop) billed me for 500ml of Dot 5…. wtf? Pulled the bike out again and flushed all 350 ml of the Dot 4 through the clutch lines. Will I be good? I’ve another unopened 350 ml bottle of Dot4 with me…

Let's hope that they actually used DOT 5.1.......

Must have. I’d’ve had problems by now.
So I’ve had a scotch, and calmed down a little.

I agree. You'd have issues by now...
Just keep an eye on the fluid, as soon as it gets too dark, just replace it.