A couple weeks ago my clutch began slipping when rolling on the throttle around 5k rpms. Only really noticeable when the bike is warm after 20 minutes or so of riding. I typically baby the clutch and have never had it to the track but I bought the bike used so there's no telling how the guy before me rode. Been doing some reading and it seems like I may need to rebuild the clutch or replace the master cylinder. What are ya'lls thoughts? And if I do need to get a clutch kit what are your recommendations on parts/ brands?

As long as your clutch slave cylinder is not seized,( which would be unusual), then your plates are probably toast. I havent changed mine yet but in the past have used Barnett plates. But they do have a tendency to drag more than stock. The stock plates seem to work good on our bikes, so maybe use those. Use a manual because I think there are some important measurements you need when setting up the new plates.

Mad

I typically baby the clutch and have never had it to the track but I bought the bike used so there's no telling how the guy before me rode.

I'm with Mad, if you're sure the clutch is slipping it's toast. As Mad said, unless there's some problem with binding there is no adjustments for the clutch on our bikes.

Impossible to tell what caused it to wear out so prematurely. My experience with a people that "baby" the clutch often are trashing them. They think the "babying" they're doing is good when it's like the worst stuff you can do to a clutch. For example, gently accelerating from a stop and gently and slowly engaging the clutch.

Mileage?

Slips more in a higher gear than a lower gear? No difference which gear?

Only slips when hot? No slip whatsoever cold?

Aftermarket clutch lever?

Using engine oil or additives with high levels of anti-friction components?

Mine did exactly the same thing.EXACTLY.It wasn't plates...FWIW...it was the master had a plugged return hole in there.Somehow I guess the rubber internals were wearing...a piece got stuck in there...Replaced Master(you could probably just disassemble yours and check the holes in there)...it worked excellent after that and still working at 20K+ miles.It did not slip...when cold.It started slipping about 20 minutes into the rides.3rd,4th,5th.Checked for air in the lines first...that wasn't it.

Personally,I'd put off checking the plates until you can inspect that master(not the slave).Save ya a LOT of work if that's all it is.That bike looks very well taken care of...Probably nothing wrong with the plates.

* Last updated by: Grn14 on 7/24/2015 @ 7:27 PM *

Mine did exactly the same thing.EXACTLY.It wasn't plates...FWIW...it was the master had a plugged return hole in there.Somehow I guess the rubber internals were wearing...a piece got stuck in there...Replaced Master(you could probably just disassemble yours and check the holes in there)...it worked excellent after that and still working at 20K+ miles.It did not slip...when cold.It started slipping about 20 minutes into the rides.3rd,4th,5th.Checked for air in the lines first...that wasn't it.

Personally,I'd put off checking the plates until you can inspect that master(not the slave).Save ya a LOT of work if that's all it is.That bike looks very well taken care of...Probably nothing wrong with the plates.

Great point Grn. If his bike is still under warranty would that issue be covered? Would it be best to take it in?

It's got just over 10,000, it slips in 2nd and up only when the bikes warm, stock levers and I run amsoil full syn.

Thanks Grn I'll check that first. I have noticed a kind of rubber squeezing noise when I pull in the clutch lever. If there is something going on in there is it something I can get parts for or am I replacing the whole thing?

You can get the rebuild kit.Any small siltlike black particles in the bottom of the reservoir?

Fozz how about this. Take some pics of your reservoir from side and with the cap off. Any chance of making a video showing the slipping?

Consider: if the master cylinder is at fault, via blockage or otherwise, would not the slip condition (due to reduced pressure plate engagement) be ever present, regardless of oil temperature?

No.Not always.When it's cold...the 'particle'is smaller.Allows some clutch action.Once everything starts heating up...the 'particle' expands with it.Stopping flow.

Would he be wise to start with the basics first? Bleed it or just change fluid, then move onto rebuild? DOT is cheap and it maybe worth a try.
Thoughts?

I think your fluid is probably okay(no air).Unless it looks like brown sewage:0

Hey guys sorry for the delay, still waiting on the rebuild kit to come in. Pulled the master apart, there were no obvious clogged holes but there was some black deposits in the cylinder and the fluid was on the darker side. How often should it be drained and flushed?

Supposed to be every 2 years according to the service interval. I just bled my clutch system last night, that's the 3rd time this season. Somethings causing it to turn very dark, smokey. Not sure if maybe heat is burning the fluid or possibly the master cylinder piston/bore wearing down prematurely.

"black deposits in the cylinder and the fluid was on the darker side"...rubber parts wearing.There should be NO black particles anywhere.

Dumb question probably...BUT...you guys ARE using the DOT4 straight fluid,right?No 'this works better' type stuff that's out there on the internet?

I've not had any wear issues on my master(s) in 21,000 miles.Fine from the beginning.

* Last updated by: Grn14 on 8/4/2015 @ 5:39 PM *

This is my first time changing the fluid since I've owned it so I can't be sure but I've got DOT 4 to put in it. Still waiting on the kit.

This is the only noticeable wear I've found, the rubber parts seemed fine, just the marks on the metal and nothing on the inside of the cylinder walls.

Hope this works for ya.I think it will.

There were some clutch issues at one time several years ago...where the castings were NOT accurate.I had one.On my 07.Somehow the return hole was offset...brand new part.Replaced it and all was good.It was a factory part.Not aftermarket.It displayed the same symptoms as yours.So any blockage can cause a clutch mechanism to not work properly.

* Last updated by: Grn14 on 8/5/2015 @ 10:58 PM *

I'm pretty certain my issue is related to piston/bore wear. It's tough to find information online about the fluid turning grey but what I've seen mostly which best describes my issue is it turning smokey grey. This pic is from the time before, only about 2700 miles ago (7500 mile service) and the fluid looked just like this again.

Something's goin on...it should stay a clear for a while,then begin to turn a mild yellowish.It shouldn't be grey...especially with the low miles you have on this new batch.

You are getting the cap seated all the way,yes?(no moisture getting in?)How about running your finger on the cap material(the rubber diaphram).

Any black residue on your finger?

* Last updated by: Grn14 on 8/6/2015 @ 9:49 PM *

My bore hole should have a 'mirror finish' and I never clean that bore with anything rougher than what I wipe past my asshole with. If I sand down the finish I increase the bore by millionths of a... Asshole! You broke-out of the tolerance. Who told you to 'sandaflor?'

Oh, you mean only wax on and wax off? Basically, the less you touch it, the better off both of you are. I think Dear Abby said the black has to come from line or rubber decomposing and would aluminum cause the color or would black induced oil is how rubber is made from a rubber tree, right? White sap, now add oil for so and so compounds, yes?

Dear Abby wrote too about how about you contact clean the aluminum dust off of that polished finish and what remains is gray powder. Is there gray powder off of a polished finished bore or is the bore kind of scruffed off and now looks [as] gray and is the same as the larger--darker gray ring of the plunger [scroll up].

Would aluminum float in the oil and cause the color or would a darker color like hose line, plunger rubber parts more point the way. I'll take 'make my parts out of pure rubber to last forever, oops, wrong answer.'

Oh and just for laughs, when I worked up that ape site, guys crying how black their oil became in such a short time was the OE oil on mine too.. and wink-wink, I do not use the rear brakes so no aluminum wear, correct-dough-moon-dough is to bet me.

Then dis one; 'I had to hang my caliper up on the rafters,' kind of follow the leader now on this site. They tried every which way to get the bubbles out once they saw how black the oil became. From the dealer--site owner to the clown they followed about removing parts off a bike for a bleed, tell me this is flat the fuck out frightening is; no it is not.

It is what it is, will be, always will is rafter boys refuse to milk a titty without tool in hand, is this one simple move they refuse to apply. Some have it and others find some sort of vertical validation... place hand over mouth and begin

Syn is the slip? Where is the clutch pressure plate in relation to the clutch outer fork tangs? Remove oil cap and inspect. Maybe the OE was just as much a baby to the clutch and not too much wear... Only a capull tell.

* Last updated by: Hub on 8/6/2015 @ 9:45 PM *

Senior moment said he remembered removing the seat on the 14, has the same MO attacking that rear foot pedal. Disc is hardly scuffed, pads are brand new that came with the bike. Oh would you lookey there, same black oil might be from the rubber cap? If I do not plunge down on the rear pedal so as to whoosh the oil to circulate, might be the rubber cap and look how the rez shows this oil turning black, I better flush just so it keeps clean. So he came back from the garage and the color is... Clear as when I replaced it... oops, senior moment again was to write it down bit didn't... so say a year or close to it; since I gave it a better look just now.

Alright gang. I changed out the replaceable parts in the master cylinder... same results. The clutch is still slipping when accelerating. So what's next? Changing the entire master assembly?

Have you looked at the slave cylinder?Possibly something going on it there.Maybe the piston isn't working right.It pushes against that shift shaft.Maybe it's not returning all the way?