Joined Oct 2010
85 Posts | 3+
lock up ward
I have heard this before , i think its to do with the rubber seals [ i may be wrong ] but its not going to stop your brakes or clutch from working properly, i havent had this with mine and i think im right in saying that its dot5.1 and not dot 4 , ARE YOU A BRAKE FLUID RACIST? someone else will give you more gen , i have an oberon slave cylinder and hell lines i dont know if thats why it doesnt seem to effect mine.pippip
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well mine was black too
after emptying the res and cleaning the black crap out and bleeding all's well .
the black comes from the little hose as it degrades so it will return after a while .
if you bleed it do it slow as you need to wait for the mc to refill between pumps.
undo bleeder at slave half turn pull lever and hold nip up release lever and wait for fluid to drop in res !! repeat till clear at slave
hth
after emptying the res and cleaning the black crap out and bleeding all's well .
the black comes from the little hose as it degrades so it will return after a while .
if you bleed it do it slow as you need to wait for the mc to refill between pumps.
undo bleeder at slave half turn pull lever and hold nip up release lever and wait for fluid to drop in res !! repeat till clear at slave
hth
Joined Mar 2008
3K Posts | 0+
Lincolnshire
Its will turn black, worry when you cant see anything cos your clutch is gonna stop working pretty sharpish.
Joined Sep 2011
141 Posts | 0+
Portsmouth, Hampshire, UK
It's all working fine apart from being a heavy *******, easy into neutral, smooth gear changes, no signs of slipping or anything, just greyish fluid.
Joined Sep 2009
140 Posts | 0+
Suffolk and Morecambe, (Lancs)
Leave well alone most do it, mine went black within weeks and has done on both occasions I have change the fluid. Still works OK.
Joined Mar 2008
3K Posts | 0+
Lincolnshire
Rub uncoated aluminium with a cloth and a bit of fluid. what colour does the cloth go ?
Rub an uncoated aluminium M/C bore with a piston and a rubber seal immersed in fluid, 200 times a ride and what colour does the fluid go. = Aluminium Oxide colour
Unless the M/C and slave bores are hard anodised which they aren't on the oem kit you won't stop it. Every Brembo based bike i have had does the same. If you fit an aftermarket slave it slows down the process as they are hard anodised but it still comes back from the m/c.
The clutch has a much longer stroke with each use than the brake so the process is quicker and the caliper pistons of the brake are steel not aluminium.
Rub an uncoated aluminium M/C bore with a piston and a rubber seal immersed in fluid, 200 times a ride and what colour does the fluid go. = Aluminium Oxide colour
Unless the M/C and slave bores are hard anodised which they aren't on the oem kit you won't stop it. Every Brembo based bike i have had does the same. If you fit an aftermarket slave it slows down the process as they are hard anodised but it still comes back from the m/c.
The clutch has a much longer stroke with each use than the brake so the process is quicker and the caliper pistons of the brake are steel not aluminium.
Joined Aug 2011
901 Posts | 0+
West Sussex
Spoonz, here a question for you and anyone else..
I`v noticed that if I sit at lights, or railway crossing say, engine running, in gear, holding clutch in. Over time its seems as though the biting point of my clutch come in more and more.
I normally use two fingers on the clutch, with the others behind the lever gripping the bar. But after about 2mins I guess I have to move them so I can pull the lever back to the bar to stop it dragging, even then after awhile it will start to drag. Its actually stalled the bike before. Is this just a change of fluid needed you think? or a by product of the crazy vacum clutch system these have??
As soon as I can release the clutch out again its back to normal. Must be fluid? I`m used to cable clutch...
I`v noticed that if I sit at lights, or railway crossing say, engine running, in gear, holding clutch in. Over time its seems as though the biting point of my clutch come in more and more.
I normally use two fingers on the clutch, with the others behind the lever gripping the bar. But after about 2mins I guess I have to move them so I can pull the lever back to the bar to stop it dragging, even then after awhile it will start to drag. Its actually stalled the bike before. Is this just a change of fluid needed you think? or a by product of the crazy vacum clutch system these have??
As soon as I can release the clutch out again its back to normal. Must be fluid? I`m used to cable clutch...
Assuming it's not a leak then it's probably the fluid. The slave gets very hot generally but very much so in traffic at idle. Any microscopic air particles or moisture in the fluid will expand and reduce the fluid pressure as they do. when you release and re apply the clutch you temporarily re pressurise it.
On my 04 bike when i toured Spain every year i carried a spanner for the M/C bleed nipple. Every time i had been in major traffic in spanish heat i would stop and crack the nipple and a tiny amount of air would pop out. You always knew when to do it for exactly the reason you mention (creeping etc). I had an MPL slave, 2 different M/C revisions under warranty and it still did it. In the end i had an aftermarket M/C and Brembo Gold fluid and all good.
The early Brembo radial M/C's were the worst, the heat of the fluid would cause the seals to soften and allow air in. Pre radial m/c's are pretty good and it's usually fluid degradation or air that causes issues. Only recently have Brembo cracked the issue on the radial stuff (Ducati etc had same issue at the time so it wasn't an Aprilia issue). Hence the RSV4 went cable as it runs hot hot hot.
Generally top notch fluid changed more frequently is the best way to minimise it.
There was some testing done on Af1 trying to reduce the slave temp to help the issue. A spacer of heat resistant material between slave and casing was machined. Without it using a laser thermometer to test the temps the slave ran at 106 degrees on the test steed. The engine casings at about 100. That's a lot of temp for the clutch fluid to be subjected to almost the entire time you are riding. At least the brakes have no heat when not used. The spacer did help by all accounts but a Brembo racing M/C also was a fix as it's designed for high temp engines and that is the route i took.
Bit of a long winded reply to the question but basically whack some new fluid in there. When you bleed it use a syringe and don't immediately recycle the expelled new fluid back into the system, keep using fresh. The air bubbles in it take up to 24 hours to rise out of the fluid so you will just recycle tiny air bubbles back into the system.
Joined Aug 2011
901 Posts | 0+
West Sussex
Cheers bud
...thats what I thought
hahaha
Must get meself a syringe!
How much was you m/c? always fancied an uprated one, but so pricey...
Joined Oct 2010
646 Posts | 0+
cheers Spoonz, I wondered why the v4 was cable clutch!.
SteveR matey, go for it RE the Brembo radial brake and clutch pumps, makes a huuuge differnece in operation and feel, priceyish new but s/h theyre not too bad
ck
SteveR matey, go for it RE the Brembo radial brake and clutch pumps, makes a huuuge differnece in operation and feel, priceyish new but s/h theyre not too bad
ck
They do lots of versions of the Race m/c 's The cast versions are the cheapest which is what i had. I think i paid about £190 but it was 5 years ago. The forged versions are quite a lot more and the folding lever adjustable ratio ones are mega.
Mine came from these bods Clutch M/C's
Mine came from these bods Clutch M/C's
Joined Aug 2011
901 Posts | 0+
West Sussex
CK - "priceyish" says the man who is happy to replace everything with carbon fibre!
Spoonz - which ratio etc did you get? I think this bike is a keeper so will probably invest at some point as always fancied a fierce brake set up for when I`m on track.
£190 is pretty good for a new one! did it have a brake light switch?
Spoonz - which ratio etc did you get? I think this bike is a keeper so will probably invest at some point as always fancied a fierce brake set up for when I`m on track.
£190 is pretty good for a new one! did it have a brake light switch?
