Clutch slow to engage

[Traveler]

Ok, I have been reading and searching all evening. Just got done reading OoPEZoO's postings of replacing his clutch and spline shaft. Don't really want to do that, but... Am keeping the bike come hell or high water and will be going to the Grand Canyon with it in June, so I need it to be right before then.

 

So, here are the symptoms. When I am taking off (mostly with wife on board taking off from dead start on a slight up hill) the clutch will slip taking off. What I mean is, I can completely release the clutch and it slips and then catches itself in a second. Sort of like having a semi-automatic.

 

The clutch shows NO signs of slipping any other times. I have tried everything today on our 120 mile ride two-up to make it slip. It ONLY slips on takeoff and only for a second until the clutch seems to completely engage.

 

So, what can cause the clutch to "slowly" engage despite letting go of the clutch lever completely?

 

BTW, the clutch engagment point vs lever position does not seem to have changed in the last 40K miles at all.

 

Bike: 2004 RT

Miles: 40K

Oil: Mobil 1. Never any of the Amsoil crap... :>)

 

Any and all advise will be appreciated.

[Traveler]

Wow! People are slow to comment this evening. Must be nice out and everyone is tired from riding all day?

[Haynes]

If your clutch is not worn and all hydraulics and freeplay are correct then some oil on the clutch is a possible cause of slippage.

Do you smell anything other than heated friction material?

 

I too have a 2004RT and carrying my wife on an uphill start requires careful throttle/clutch co-ordination. I try to keep the revs fairly low and get the clutch right out and into direct drive as quickly as I can. Mine doesn't give the excessive slip that you describe.

Is it possible that you're using too many rpm on takeoff?

[RTCHIEF]

The clutch cable.

[Haynes]

The clutch cable.

The clutch is hydraulic.

[Traveler]

No. I am doing nothing different than I have done for the last 40K miles. It is literally like the clutch will not engage quickly. I let go of the clutch lever completely while at about 2K revs. The bike goes and over about 1-2 seconds, the clutch engages and then off we go.

 

It did not used to do this at all. Is there something that can cause the clutch to stick disengaged? Once it DOES engage, there is definately positive engagement. No slip at all under any load or RPM. Just the physical clutch does NOT engage at the rate that the lever is released.

 

BTW, been riding for over 350,000 miles in my life. This is something new to me. I have had bad clutches on bikes before, but this one is weird.

 

If it were a cable type clutch actuator, I would think that the cable was sticking. But with hydraulic actuation and the fluid level being the same as always and the release point not having shifted, I am at a loss.

[realshelby]

Traveler, the way the pressure plate/disc/release method is set up on your RT would not likely be causing your problem. If you cannot get the clutch to slip in the higher gears it probably does not have the dreaded oil leaks affecting it. I would look closely at the slave cylinder and master cylinder. Do a fluid flush first as that is easy and the pumping of the master cylinder and moving the slave back and forth as you blead it may make a difference. I am guessing you have one or the other sticking.

 

I say this because holding in the clutch lever at a stop light holds the piston in place for a while allowing it to "stick" whereas shifting up and down while moving is a steady motion not allowing it to stop in one place long enough.

[OoPEZoO]

When mine started slipping, it was not noticeable either until I had a day of riding with my fiance on the back with lots of stop and go traffic. It did it especially when the bike had cooled off, and when taking off on an incline. Once we got moving and the disk got heated up, it seemed to perform a lot better. When riding solo after that, I could get it to slip a little under hard acceleration in the middle gears, but not 5th-6th. I could also only get it to do it at the beginning of a ride. Once I got everything heated up, I couldn't get it to slip at all. This is what was confusing to me.......I knew what a "typical" clutch failure feels like from years of driving old high mileage crappy beater cars, but this was completely different.

 

40k miles seems to be a pretty early failure for one of these bikes. Mine made it 101k miles, and was technically still within BMW spec of being "good". But it was worn down to the point that a few of the rivets in the clutch disk were nice and shiny. So I don't care what BMW's spec is, it was shot. Then I found the two leaky seals (engine and transmission) and the almost stripped out spline shaft. So I don't know if it was hitting the rivets that was making it slip, or the oil contamination that was causing it. Either way, it was time for an overhaul.

 

With what to do......I would stick with the above advice and do a complete inspection of the master, slave, and a fluid flush. If you don't find anything, or it doesn't fix the problem, then I would prepare to swing the tail in the air and get your hands dirty. The only way to make 100% sure everything is OK, is to take it apart and check it out.

 

Another thought. Pull the starter and shine a light in there while working the clutch lever. That will at least give you a look at how everything is moving. I don't know if it will tell you anything, but it will give you a better idea of how everything works. Best of luck, and don't be a stranger if you have questions.

[philbytx]

Before having a mental/financial meltdown , when was the last time you did a clutch bleed?

 

I would heartily recommend you bleed your clutch first .

 

 

 

 

[skinny_tom (aka boney)]

I'm in the "flush the fluid" camp. Make sure you do it well.

[Traveler]

I flushed the clutch circuit when I did the brakes/abs system last spring. That was about 12K miles ago.

 

I will try to get out to the garage tomorrow and begin the clutch adjustment and perhaps pull the starter.

 

Oh boy... Why didn't this issue come up last fall when I had all winter to work on the thing...

[Traveler]

If your clutch is not worn and all hydraulics and freeplay are correct then some oil on the clutch is a possible cause of slippage.

Do you smell anything other than heated friction material?

 

Why yes, I do smell burnt oil on occasion at stop signs and when pulling into the garge now that you mention it. I had assumed that it was the leaking Ohlins shock adjuster that was dripping occasionally onto the Cat. Maybe not?

[realshelby]

[quote=Traveler

 

Why yes, I do smell burnt oil on occasion at stop signs and when pulling into the garge now that you mention it. I had assumed that it was the leaking Ohlins shock adjuster that was dripping occasionally onto the Cat. Maybe not?

 

That occasional whiff of hot oil smell is exactly what I now know was the transmission oil getting on my '04 RT's clutch at 14K miles! I could get mine to slip in higher gears, not just first. Pull the slave cylinder and see if there is oil in the housing where it mounts. You can replace the seal without splitting the transmission apart. I removed the transmission in my RT and replaced the clutch disc. If I had to do over I would have tried replacing the seal while on the bike and cleaning the disc thru the starter opening with brake cleaner!

[OoPEZoO]

Oh boy... Why didn't this issue come up last fall when I had all winter to work on the thing...

 

Come on now.......you know the answer. Its because these bikes love to screw with your emotions. Love em' or hate em' (depending on the day), you have to admit that there is always some sort of emotion involved

 

Don't stress out about it. If you can spin a wrench, we can talk you through whatever needs to be done. Just keep your fingers crossed that your clutch splines are in good shape.

[Traveler]

It's not the money that bothers me. It is the time. It is now riding season and I believe that I need to take the bike down for a few weeks.

 

Or, I could always go trade it in for a 1200...

 

After reading OoPEZoO's post on his festivities, I'm not so sure I will have the patience... Already started looking at the fische to get part numbers. I'm soooo excited about this...

 

 

[Unhofliche_Gesundheit]

re; "Just keep your fingers crossed that your clutch splines are in good shape"

+1 on that.

i understand poor clutch engagement when pulling away from a standstill can be caused by splines (badly worn or simply crudded up).

not sure how to verify for this other than splitting the bike (aka the 'tail in the air procedure') for an inspection and a lube.

 

[Traveler]

Ok, so the starter is out. What am I able to tell from this view?

 

 

 

All that I can tell is that everything looks to be in it's place and that there is no sign of oil anywhere...

 

And thank you all so much for the input.

 

Randy

[Traveler]

And if the clutch splines are NOT in good shape, what is the worst that can happen? I do the same as you had to Keith?

 

So long as I don't have to open the engine, I feel pretty comfortable in my abilities. But after that, It goes to the dealer in pieces...

 

So, since I have a hydraulic clutch, there in no adjustment to make correct? And since I replaced the fluid last year it should still NOT be the issue.

 

I have not pulled the slave cylinder since I am waiting for a possible response on these pictures. BTW, they are two seperate pics at different ISO settings for different brightness.

 

Took about 45 mins to get the starter out. Once I figured that I needed to remove the footpeg mounts to get to the rear starter bolt, everything went quickly. The Haynes manual was actually OK for this procedure...

[T__]

 

Difficult to tell from angle of the picture but the front side of disk looks worn more than the rear.. See if you can get in there & measure the disk thickness..

 

 

Twisty

[Traveler]

Ok, off to see if I can fit in some caliper or something in there. Maybe even a different angle on the pictures.

 

Thanks! BBS! (Be back soon)

[T__]

Traveler, pull the clutch lever in to move the plates apart then use a tie strap to hold it there.. Then look to see if there is lip on the front plate that is skewing how much of the clutch disk we are seeing..

 

 

Twisty

 

[Traveler]

Ok, so the clutch thickness came out at 14/64ths. AKA 5.56mm. Close as I can get with the sliding machinists rule that I have.

 

Here is a slightly fuzzy picture that shows better that the clutch seems to be even on both sides.

 

 

So, the clutch wear is not the issue?

[Traveler]

The "brighter" of the 1st two pictures was taken with the clutch lever pulled in. No lip there.

[T__]

Traveler, that is a much better view of the disk thickness.. Well I don’t see any signs of oil or clutch fluid in there & not a lot of rust & the wear seems low..

 

What happens when you pull the clutch lever in then quickly release it while watching the clamping action on the pressure plate & disk? Can you see it snap quickly & tightly together?

 

Twisty

 

[Traveler]

Twisty,

 

I just went out and played with the clutch for a while.

 

The clutch seems to exactly follow whatever I do with the lever. Snaps shut when I let the lever snap etc. I even held it for a while and then let it snap and it follows exactly.

 

WTF?...

[OoPEZoO]

Hmm......like Twisty said, it doesn't look like you have any oil contamination. Beats me man, everything looks like it is in order. The only way to be sure is to get that tail up in the air and start unbolting stuff. I hate to say it, but any thing else is just speculation. If you just have to replace the clutch, you could do it over a weekend if you really want to get it done.

 

and yes, if you get in there and find that the clutch splines are going out......then you will have the choice of replacing the input shaft, or finding a replacement transmission. Been there, done that, and I wouldn't wish that decision on anyone.

[T__]

Traveler, baring some fairly heavy clutch disk glazing or weak pressure plate spring I sure can’t see any signs of heat damage,, engine oil,, or clutch fluid..

 

About the only thing I can think of & a long shot at that would be a plugged take up port hole in the bottom of the clutch master cylinder..

 

When the clutch lever is let all the way up the piston uncovers a very small hole to allow either more fluid to enter the cylinder or allow any fluid pressure from heat expansion of the fluid in the system to escape back into the master cylinder..

 

If that hole is plugged or the piston isn’t returning far enough to uncover that hole it could allow pressure to build in the lower clutch hydraulic line & slave cylinder & hinder a full clutch engagement..

 

If you want to check that-- first completely cover your Tupperware & dash under & around the master cylinder with plastic bags & newspaper.. Brake fluid is a fantastic paint remover..

 

Then remove most (but not all) of the clutch fluid from the master cylinder..

 

Then work the clutch lever slowly (watch for fluid shooting up so start off easy).. If you can see fluid flowing back into the reservoir just as the lever is released all the way (a little shooting up through the small hole) then it is open & the piston is uncovering the hole..

 

Otherwise I don’t have much to offer you.. Hopefully with the pictures maybe someone will notice something fro you..

 

Twisty

 

[Traveler]

Ok guys. So, for now, I am going to pull the cover off the reservior and inspect as Twisty suggested. (done with tupperware still off to preserve it from flying brake fluid...)

 

If that looks good, I am going to put it back together and ride it like I stole it for a week. If the clutch only slips on rare occasion and NOT during driving, (just take-off with wife on board up hill) then I am going to leave it alone until it gets worse.

 

Just hope that the "gets worse" doesn't happen while 2000 miles away in AZ this June...

 

Thanks all. I am really happy that I got the advice to remove the starter and take a look. Since the clutch thickness is way above mimimal, I am not going to worry too much.

 

Back to the occasional burnt oil smell, I can only imagine that I might have a very small leak in a seal that puts a small amount on the clutch that builds up minimally during longer stops and allows for slipping during take-offs. May burn off once underway?

 

Anyhoo, I'll put it back together tomorrow night. 4:30 comes early tomorrow morning.

[Traveler]

Keith, if it gets worse...

 

I'll be asking you for a "parts to order" list...

 

Thanks all!

[OoPEZoO]

Its all good man.....best of luck. I have my fingers crossed for ya.

 

If you have a small/slow leak........you can usually tell by shining a light in between the transmission and catalytic converter. If you have a leak, then you should see some sort of grime built up on the bottom of the transmission. I always dismissed mine as collected road grime, but after my adventure I realized that it was sludge built up from miles and miles of oil seepage. Since the rebuild, the bottom of my transmission is dirty and dusty, but there is no sludge/grime.

[Boffin]

I have just read through the posts. FWIW, when loaded or trying to pull off withslightly too-high RPM, both of my RTs have done this. What I do now is just to back-off the throttle slightly. This lets the clutch hook-up and then you can open the throttle and go. I aim to have the clutch fully engaged by 1500RPM.

 

Andy

[RTCHIEF]

When at speed what RPM is the tach showing? Shifting gears?

[Traveler]

This has only occured at take-off. Only once warmed up.

 

Never occurs at any other time but during take off.

 

I'm going to check the master cylinder and look for leakage at the slave as well as leakage under the tranny.

 

I am thinking that I might have an issue with air in the hydraulics that expands once heated up.

 

Or at least I'm hoping...

 

I will do a bit more investigating this evening. Gotta go get some brake fluid on the way home and will empty the master cylinder and check for proper operation and will do another complete bleed of the system after checking for leakage at the slave and under the tranny.

 

[Traveler]

I never rev the engine above 1.5 - 2K during any take-off. Generaly don't apply much throttle at all either.

 

Weird that it will allow complete release of the clutch lever and will slip for a second and then completely catch and never slip again during shifting or under any load at any RPM either.

 

I have tried to fully load it at all RPM and never get any slip at all once underway.

[Traveler]

Boffin, what are you doing up at 3 in the morning!

[Traveler]

Boffin, what are you doing up at 3 in the morning!

 

Oh, nevermind, I just saw where you are from... Imagine it is raining there. :>)

[Boffin]

Boffin, what are you doing up at 3 in the morning!

 

Oh, nevermind, I just saw where you are from... Imagine it is raining there. :>)

 

It has been a nice spring day here so far, but clouding over now.

 

Andy

[realshelby]

My RT did not show ANY sign of oil leaks externally. The hot smell was from the disc itself, as even during normal cruise the oil was causing some amount of slippage and therefore heat=hot oil smell when stopping. Only got a whiff of this the moment I stopped. There was no heavy evidence of oil on the clutch assembly. It was obvious on the disc once apart. You might be able to see a sign of the oil ( if any) on the clutch hub. The only way to know if it is the rear seal ( most common ) causing the problem is to pull the slave cylinder. If it is not dry, there is your problem.

 

[Traveler]

Ok, so I just got done inspecting under the tranny and around the slave cylinder. Nothing but dry road dust. No grime at all.

 

I then put a BUNCH of fluid through the hydraulics to bleed it after doing the inspection on the master cylinder that Twisty recommended. The fluid was as clean as the day I put it in, but I figured that I would bleed it just in case I had air in the system. (I used the same speed bleeder that I used when I did this same procedure last year). Not sure if the bubbles I saw come out were from leaking around the speed bleeder or from the slave cylinder. But, eventually there were no more (tiny) bubbles and I put another 1/3 of a quart through it to be sure. "If some is good, more is better" right?

 

I will look at the hub.

 

Thanks guys! Still moving forward...

[Traveler]

Ok, just looked at the hub. Dry as dust. I could actually see behind the hub and see the splines that come out of the tranny. Also dry as dust.

 

I'm thinking that any leakage out of the tranny seal would drool out while she has been sitting there or at least would show evidence of leakage that had occured during the last ride.

 

I could actually get down under/beside the bike and see around quite a bit of the splines that go into the hub and come out of the tranny and there is no evidence of any oil ever being there.

 

Still hoping that bleeding the clutch hydraulics will have done the trick. I see no evidence leading me strongly in any other direction at this time.

[Boffin]

One point to remember - the clutch fluid should be filled to the {b]lower[/b] mark on the level indicator, as the level rises with clutch wear. The resevoir is often incorrectly filled to the top-mark, even my dealer used to do it. I have seen over-full clutch reservoirs cause slippage.

 

Andy

[Ken H.]

The only way to know if it is the rear seal ( most common ) causing the problem is to pull the slave cylinder.

+1

 

If it was me, before I’d decide on the ‘just ride it’ option, I’d pull the slave cyl. and see what if anything is up in there.

 

[pjw73nh]

My two cents..

 

First my experience then my thoughts (FWTW).

 

Experience: Before my spline surgery, I would experience what Traveler is experiencing re clutch not fully engaging (locking up) after coming off of a start. MY difference is that I rarely rode 2-up and it would always happen when it was cold outside. IE 35 deg F or lower. As the bike warmed up after 15 miles or so, the symptom would go away. Again, this was only one up riding, only from a stop in first, and only when cold. I would also feel some slight "stiction" in the clutch lever.

 

 

My thoughts: I know there are a lot of variables here but FWIW I thought I would post it. In mid January I had the clutch/spline shaft surgery and all that goes along with it. Including (among many parts) see attached clutch pic items 2-8, a new clutch slave cylinder, a new push rod and felt ring/washer, and new spring.

 

During the repair process I was able to stop in at the dealer a few times and have a look-see. The slave cylinder and pushrod and felt were gummed up with gobs of "chocolate". Most likely a combination of bearing grease and brake (clutch) fluid.

 

When I got the bike back it was still very cold out. Now granted most of the clutch system was brand new so it's hard to say what ULTIMATELY solved the stiction and slipping , but it was totally gone and if felt like I was riding a new bike. Even down as low as 20 deg F.

 

My guess is that it was either the gummed up pushrod and felt, or the slave cylinder, and that as the bike warmed up, the "gum" became thinner.

 

As far as the OP? Could it be a weak spring?, bad slave cyl, or gummed up pushrod?

 

Good luck with it.

 

Paul.../NH

 

PS. Sorry it wouldn't let me add the second pic.

[Traveler]

One point to remember - the clutch fluid should be filled to the {b]lower[/b] mark on the level indicator, as the level rises with clutch wear. The resevoir is often incorrectly filled to the top-mark, even my dealer used to do it. I have seen over-full clutch reservoirs cause slippage.

 

Andy

 

So I wasn't supposed to fill it to the top of the viewing window... Guess its back to the garage. Last time I filled it, it was just above the top of the window when the bars were turned to make the fluid level in the reservior. I will go take some out and put the bike back together this evening. Perhaps this is what is was all along...

 

One can only hope.

[Traveler]

So I took some of the fluid out of the reservoir to make it come 1/2 way up the sight glass. Buttoned it back up, installed the starter. Buffed up the exhaust system with brass wire brush and 0000 steel wool. Then installed the foot peg bracket.

 

Then I got hungry and ate dinner and now it is time to hit it.

 

I sure hope that this does it because I really don't with to take it all back apart again. But, if it comes to that, I will just order the parts for a cylinder replacement and try that next.

 

If that doesn't look like the reason, then I guess I am stuck doing the same as Keith did...

 

Sure was nice out today. Would have been nice to ride to work.

 

Whine whine whine...

[Traveler]

Ok, so I just took it back out to warm up and test from a take-off.

 

Slips at hard take-off bad enough that I had to let off the throttle to get it to catch.

 

Next step?

 

Here are my thoughts:

 

1. The clutch is not worn out.

2. The fluid level did not go down in the clutch hydraulic master cylinder. Nor was the fluid discolored.

3. There is no apparent leakage on the clutch hub or splines.

 

So, I will start by pulling the slave cylinder and inspecting it. If it is good, then I go tail up and remove the tranny. See what parts need replacing.

 

It is 55 degrees and sunny here today. Supposed to be 60 degrees and sunny tomorrow. I miss my Goldwing...

 

[OoPEZoO]

Sounds like a good plan of action. Best of luck

[Traveler]

Now in the process of going "tail in the air". I don't care if it is just the damn cylinder anymore. It's getting fixed. One friggin way or the other.

 

While in there I might as well send off the Ohlins for rebuild. Gonna lose the bike for a few weeks. Might as well do it right.

 

[Traveler]

Did note that Beemer Boneyard has the slave cylinders for $99 however. Have had good luck with them in the past and this represents a savings that would be foolish to ignore.

 

Just for others info...

[realshelby]

What did you find when you removed the slave cylinder? "Tail in the air" is a last resort, I have done it. You mentioned buying a slave cylinder. Make sure you do NOT have a slave cylinder or master cylinder sticking before you tear it all apart.