Adjusted the clutch after replacing the friction plate/o-ring and for some reason, the minute I pull the clutch-lever in and put the bike in gear on the center stand, the wheel spins. Readjusted it many times following the adjustment procedure exactly, but get the same result. Thoughts on what might be causing this? I surly hope I don't have to take the tranny off again. It's almost like the clutch rod isn't floating the clutch plate.

is it spinning with some force behind it or if you were to just stop the wheel with your hand does it just stop?

twincarb wrote:is it spinning with some force behind it or if you were to just stop the wheel with your hand does it just stop?

Good question, guess that would mean the clutch is somewhat engaged if I can stop it with my hand, I'll check and let you know.

reason i ask is i cant remember if it was my k that did it as well.... I put it down to just vibration through the bike causing it to happen with there being nothing in line to actually stop it...

If there is no "force" needed to stop it i wouldn't have said there is anything to worry about...

May be easier to use the rear brake than your hand TSBT.

sidecar paul wrote:May be easier to use the rear brake than your hand TSBT.

Thanks Sidecar I was going to say don't want to loose a good arm.

I wouldn't worry if you can easily stop the wheel with your hand.
The best test is to try to shift gears. if it's smooth, it means that the clutch is doing the job.
You may have a high spot on the disk, and that would drag the clutch if there is no resistance. When the friction plate will wear a bit, everything should be OK.
Just go for a 10km ride and see what's happen after that.

CF

Crazy Frog wrote:I wouldn't worry if you can easily stop the wheel with your hand.
The best test is to try to shift gears. if it's smooth, it means that the clutch is doing the job.
You may have a high spot on the disk, and that would drag the clutch if there is no resistance. When the friction plate will wear a bit, everything should be OK.
Just go for a 10km ride and see what's happen after that.

Thanks for the suggestion Crazy Frog, any excuse to go for a ride! Guess I'd better keep my hand and foot on the brake eh? Hopefully that's all it is. The bike actually moved sitting on it and I had to hold the brake in last night when I put it in gear. The gears do shift all the way up to 5th and back down on the center stand. I'll try that after the hand test. thanks a lot.

All 3 Ks of mine have done that especially the 75 which was very bad but they all settled very quickly and are OK now

Rick G wrote:All 3 Ks of mine have done that especially the 75 which was very bad but they all settled very quickly and are OK now

It's funny Rick, tried the Crazy Frog/Twin Carb suggestion and held the wheel and she just won't stop spinning with the clutch in. Taking it apart to see if there was something inside the boot/bearing/rod area that wasn't seated properly maybe the rod got hung up on something. Failing that I guess I'm talking the @$*%#* tranny off again :bom:

None of mine were that bad even the 75 wouldn't do that. It just was hard to find neutral and down changes were a bit clunky if you can tell the difference.
I would have to investigate a bit futher. You didn't by chance hang the gearbox on the spline and buckle the plate. Haven't seen a K do it but some cars.

Boot off. Clutch rod out. Still no clue. Next step: commit to removing the tranny again. This is killing me.

Rick G wrote:
I would have to investigate a bit futher. You didn't by chance hang the gearbox on the spline and buckle the plate. Haven't seen a K do it but some cars.

Might be at that point.

Check the pushrod for straightness, it can affect the clutch adjustment.
Roll it on a piece of glass.

I'm wondering what the resolution to this issue was. I'm experiencing the same thing. I pulled the transmission to lube the input splines and when I put it back together I can't get the clutch to disengage.

I pulled the transmission off again and the release pushrod is straight. Everything lines up correctly in terms of adjustment. I had a "spare" (new) clutch cable previously installed on the bike so I replaced the "old" cable but that didn't help.

Other than hard downshifting, the reason for lubing the input splines, the bike shifted correctly prior to doing this work.

If I have a helper hold the rear brake and I put it in first, the engine speed is cut in half and I cannot get the transmission back into neutral until I have my helper release the rear brake.

Anyway, if anyone knows the resolution to this thread, that may provide me with some more information on how to resolve this.

Thanks,
Tom

All good. Had the clutch assembly in the wrong order. Friction plate was in the wrong spot. Had a feeling it was after reassembly. Fixed. Gut was right. Went on a 2k ride afterwords. Good luck!

Bummer, for me (great for you). I have not touched the clutch itself and was working so it should be assembled correctly.

That's where I'm prolly headed though. Pull the transmission again and pull the clutch for inspection.

Thanks for the response,
Tom

When you get it sorted Tom, jump a plane and come over here, you;ll be able to do mine in a flash.
Good luck mate
RT

Have also seen your thread at motobrick, and that you need to turn the
adjuster screw way to far in.

Since the clutch haven't been disturbed, it isn't that much possibilities...........
wrong adjusted cable, or incomplete/wrong mounted throw out bearing/piston.

Tom when you pull the clutch lever in does it pull all the way to the grip easily or does the last bit get tight.
If it is like that then the throwout bearing and piston may be bottoming out in ite bore thus preventing the clutch fron disengaging. I recently had the gearbox out of my K11 and the pushrod came apart (the steel insert on the clutch end came out of the alloy pushrod) now I just replaced it but on thinking if yours is the same then where the insert fits into the pushrod could be spinning with the clutch and wearing away till it is too short. Only an educated guess but it came to me when Inge said about the adjuster being in too far.

Inge,

I keep thinking the same thing. But, I've inspected and adjusted the clutch eight ways to Sunday and everything looks "right". It just won't disengage.

Rick,
When I pull the lever it is smooth as buttah all the way to the grip. Part of this odyssey has been replacing the clutch cable with the new "spare" I had previously installed on the bike. While the old cable didn't seem stiff, it is much easier and smoother to pull now that the new cable is connected.

I don't see any unusual wear on any of the mating surfaces on either end of the pushrod.

Also, as Inge mentioned, if I adjust the screw "in" too far, the clutch will disengage (the plates are not "stuck"). In that configuration, the cable is very tight (w/o touching the lever) and if I attempt to ride it, the clutch slips (bad). Essentially, it is "disengaged" by virtue of the screw in too far and the cable holding up the other end of the lever.

I'm going to head out to the garage and start pulling it apart [again]. I'll post pictures of the parts in question before I pull the clutch. Maybe someone can see something I don't.

Thanks for the inputs,
Tom

What's the clutch arm like.

ungaas wrote:What's the clutch arm like.

It appears to be fine. It fits and rotates on its fulcrum easily.

When this is over, I'll prolly replace the clips with something better. Regular snap-rings or something. The factory clips are pretty cheap.

I got the transmission out and took some pictures. It'll take me a bit to get them sized and attached to this thread. But they'll be here soon.

Tom

As I think about it. Increasing the length of the pushrod won't change anything, it'll just require less "adjustment" of the screw. What it seems to need is a longer arm on the adjustment side of the fulcrum. That would allow longer travel when the lever is pulled.

Tom

those clips are really crap ...surely for another 5 cents something better ....

I have been thinking about this and no matter which way I go I keep comming back to the pushrod being too short (or that effect) and that prevents the clutch disengaging when the adjuster screw is in the correct position and the cable and handlebar lever are OK. Then you adjust the screw in so that it does disengage and the cable is real tight and the lever wont come to the handlebar. What this says to me is the throwout bearing under the rubber boot is going too far down its hole and bottoming out so making the cable tight and not far enough back so causing the clutch to slip. If the throwout bearing was bad it could have the effect of the pushrod being shorter than it should be. Is the back half of the throwout bearing in place, that would be just the right thickness to have the effect if it was missing.
I have a pushrod here which is from a K75s that I am fixing for a friend and measured it
LOA, 253mm, spigot on front end is a gnats dick short of 35mm and the spigot on the back end is the same amount under 7mm.

I have been sitting and looking at the K75 I have here for ages and it is the only conclusion that I can come up with. The whole thing has me intrigued.

If you haven't taken the rubber boot off then the back bit of the throwout bearing could slip down into the boot if the clutch arm was folded back. You possibly wouldnt notice this unless you took the boot off.

Here are some pictures I took.

[img][/img]
This is the piston in the transmission before I pulled the transmission. It is sitting against the pushrod which is sitting against the friction plate.

[img][/img]
This is the cylinder after removing the piston. Transmission is still installed as is the pushrod.

[img][/img]
This picture shows the throwout bearing in the piston. It is basically flush with the end of the piston.

[img][/img]
This picture shows the back-end of the piston where the spring sits in the groove.

[img][/img]
Here is the pushrod next to a ruler. Sorry, I'm not much of a photographer.

[img][/img]
Here's another picture of the pushrod next to the ruler. It appears to be about 250mm long.

I didn't take any pictures of the arm but it looks pretty much like any other.

Rick,
I'll take some better measurements of the pushrod, but as you can see, the T-out bearing is flush with the piston. One thought I had was to place a washer on the pushrod between the shoulder (on the pushrod) and the friction plate to increase the effective length. But that is excessive, "red-neck engineering" even for me.

The pushrod, from the end to the shoulder on the rear end is 6.9mm and the other end to the shoulder is 35.2mm. The overall length is probably between 250 & 253mm.

I also re-read your last post. And, I have one correction. When I adjust the screw in such that the clutch will disengage enough to take the bike out of gear with the rear-wheel stopped (no load on the gears). When I let off the lever, the cable is still tight (of course, the clutch isn't really engaged as it slips by virtue of its ill-adjustment). And, the lever DOES go all the way to the grip.

The T-out bearing seems to roll smoothly too.

Any ideas are appreciated.
Tom

I missread what you posted there, Sorry.
Possibly the center of the diaphram spring is worn but as it was working OK it doesn't seem likely.
I'm sorta right out of ideas but it wont stop me pondering it.

To my jaundiced eye the picture of the push rod looks different to what motorworks carry, have a look on their site and compare.

ungaas wrote:To my jaundiced eye the picture of the push rod looks different to what motorworks carry, have a look on their site and compare.

That is a K100 pushrod the K75 is different.

Hi there
Mi guess is that if you can operate the clutch but need more travel than default, the problem is the spring diaphragm.
Best regards
JAP

Rick G wrote:

ungaas wrote:To my jaundiced eye the picture of the push rod looks different to what motorworks carry, have a look on their site and compare.

That is a K100 pushrod the K75 is different.

OK - did look at the original post but did not see a 75 listed on his profile.

My apologies, 1) I usurped the original thread and 2) my bike is a '95 K75RT.

Tom

japuentes wrote:Hi there
Mi guess is that if you can operate the clutch but need more travel than default, the problem is the spring diaphragm.
Best regards
JAP

The spring appears to be in good shape. And, when the clutch linkage is properly adjusted, the spring is mostly compressed.

And, if I adjust it to the point where the spring is completely compressed (no "slack" at the lever), the clutch still won't release completely.

I'm either doing something wrong or there's something wrong with the parts. But, the instructions for adjusting the clutch are not that complicated and the parts look good (to me).

Rick G wrote:I missread what you posted there, Sorry.
Possibly the center of the diaphram spring is worn but as it was working OK it doesn't seem likely.

That's what I originally thought too. The bronze (looking) center of the spring is recessed "in" a bit (1.5 - 2.0 mm) but I saw a picture of a new one and it was recessed too. So, I don't _think_ that is the problem either.

I'm outa ideas. I suppose I could be doing something wrong, but I can't imagine what.

Tom

This could be a touch difficult as you need to have the spring out but have you measured the hight of the centre of the spring sitting flat on the bench. I have found 2 K100 springs over the years that have lost some tension by collapsing. 3-4 mm made a lot of difference but only made the clutch slip but the K75 is thicker in the center and it might bottom on the end of the main shaft.

Thanks Rick.

I've pulled the clutch. At least everything but the housing (the part held in by the single 30mm nut. The friction plate is well within spec for thickness.

I looked in my manual but it stated that BMW does not have a spec for the height of the spring.

Prior to all that I pulled the arm, rubber "cup" and piston out of my '90 K75 to see if there was any difference and I didn't see any.
1) The depth of the piston in the cylinder when pushed forward was about the same.
2) I did notice that its cable was adjusted to about 84mm on the end instead of 75mm. The arm was almost hitting the exhaust can when the lever is released. I had noticed that earlier and attempted that setting on the '95 K75 but that didn't solve the problem
3) I noticed that the adjuster screw on the '90 was "hand tight" once the lock-nut was loosened. This was in line with how I had been setting the screw. Screwing it as far as I could by hand which was compressing the coil spring all the way until the screw was tight against the piston and all the slack was taken out of the pushrod, cable, etc. So, if this other K75 was correct, I think I was doing it right.

I'm going to replace the friction plate and the spring (and the 6 bolts). Put it all back together and see what happens. I'm still not sure what the problem was though. Maybe I'll see a difference between the old and new spring.

Tom

I just measured the height of the spring from flat surface to the upper surface of the bronze bush in the center at 14.2mm.
Something I will never understand with BMW is why they didn't use the same clutch as on the K100, seems like they just can't help themselves and have to be different.

Hi Rick,

I measured the one I removed. from the "big end" to the "top" I get anywhere from ~16.5mm to ~17.5mm depending on where which radii I measure across (I'm callin' it ~17.0mm). The drop from the "top" to the "upper surface of the bronze bush in the center" is about 5.5mm. For a total of ~11.5mm.

I gotta specify "mm" cuz I usually measure in inches.

I'm not sure what 11.5mm means compared to 14.2mm other than this spring is shorter that yours. Maybe that somehow contributed to its inability to release completely?

It took a bit of prying to get the clutch parts out of the bell housing but I suspect that is pretty normal. No oil or grease residue but a lot of black dust (friction plate residue). The dealer was closed Sunday & Monday so tomorrow I'll swing by after work and pick up a new friction plate, spring & bolts. We'll see.

Thanks,
Tom

Dealership didn't have the clutch plate or spring in stock. It'll be Saturday before they're in and I can get over there to pick them up.

[quote="Rick G"]I just measured the height of the spring from flat surface to the upper surface of the bronze bush in the center at 14.2mm.
Something I will never understand with BMW is why they didn't use the same clutch as on the K100, seems like they just can't help themselves and have to be different.[/quote]

It is a long story, told to me by someone who was in Research at BMW building and testing K75 prototypes, but a K100 clutch will not last in a K75. The original prototype K75s had K100 output shafts and clutches. Those blew out after an hour of high speed running. To make a long story short, the balance weight on the output shaft of the K75 is not there to eliminate vibration from the engine. This engine is naturally smooth. The balance weight is there to stop a high rpm harmonic in the output shaft of the triple that is not there in the K100 that was destroying clutches during road tests. This is why the clutch of a K75 is unique and why you need a clutch centering arbor to correctly install a K75 clutch plate where none is needed with the K100 or K1100.

motodude wrote:

3) I noticed that the adjuster screw on the '90 was "hand tight" once the lock-nut was loosened. This was in line with how I had been setting the screw. Screwing it as far as I could by hand which was compressing the coil spring all the way until the screw was tight against the piston and all the slack was taken out of the pushrod, cable, etc. So, if this other K75 was correct, I think I was doing it right.

Tom,

I don't want to question your competence but that doesn't sound right to me. Perhaps it's just the way that you have worded it.

The sequence I follow is from a BMW service manual:

1. Disconnect the cable from the actuating lever at the gearbox.

2. Push the gaiter back and measure the exposed cable length from the edge of the nipple to the exposed end of the inner sleeve.



3. Adjust the length of the exposed cable at 2 (above) by the knurled adjuster at the handlebar lever until the distance is 75mm +/- 1mm.

4. Loosen the locknut on the pushrod adjuster and loosen the adjuster bolt until it is just out of contact with the pushrod bearing.

5. Screw the adjuster bolt in until it is just touching the pushrod bearing and tighten the locknut without allowing the adjuster to turn.

6. Re-fit the cable at the release lever.

7. Adjust the lever free play to 4mm by means of the handlebar-end knurled adjuster:

Yup. That's the same procedure in my Clymers manual. I tried that and the Brian Curry method on ibmwr. Which I like a little better but they both accomplish pretty much the same thing.

The other ('90) K75 was adjusted (functionally) correct the last time I rode it. I was just examining it. The most significant difference was the 84mm instead of 75mm at the cable end. There really isn't much difference except it allows the lever to lay back more allowing (or requiring) the adjuster screw to be screwed in farther.

Tom

I learnt the hard way with the cable length in that if the adjuster is in too far because the cable is too long the surface on the actuation lever that contacts the rubber boot is at too much angle to make an oil tight seal and of course it will leak oil. Not very much but just a few drips to make a mess.

Well, the parts came in but I had to work most of this weekend so it took a while to get the bike back together.

I didn't measure the spring height as before but the bronze center was definitely not as "sunken" as on the old spring. Also measuring the height across the "top" of the old spring and turning it and measuring again always resulted in significantly different results. The new spring resulted in pretty much the same results.

Off and on over the last two days, between going into work, I got the bike back together and the initial tests have the transmission slipping and an out of gear very smoothly. Just like it should.

I wrapped some electrical tape around a drill bit to make a clutch alignment tool. Worked like charm.

I will road-test it tomorrow.

I'm pretty convinced that the spring was toast and that what was causing it to not adjust properly. Why the spring was toast when the bike was shifting properly before I have no idea. Maybe I damaged it somehow? I dunno.

Tom

Forgive me. Much thanks to all who responded, especially Rick.

Tom

Thanks Tom I really find it good when I know I have helped.
Maybe when you took it apart it was just about over the edge but as you had been riding it regularly it felt normal and then when it was put back together the fine edge adjustment point it was at just could not be found again.
I have just done a drive shaft for a friend and looking at it one would reckon that it could not possibly have been working but it was ridden here and it wasn't even the reason I was working on it.
Good to see it all OK

Took the bike for a ride today and it shifts excellently. The lever is much easier to pull which I think is a function of the new cable more than anything. I don't know why the spring went bad. The new one works as it should, so...time to ride!

Thanks,
Tom

Hooray for the ride!
Congratulations and great thread.
UJ