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  #1  
Old 06-24-2018, 09:45 PM
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A thought about clutch drag

Iím no engineer nor am I a mechanic. But this clutch drag resulting in that Ďclunkí is occupying my thoughts. Iím very aware many fine minds have been looking into this. This forum is a clearing house for ideas with an impressive worldwide array of contributors.
There seem to be many issues that contribute, on their own or some combination, to this drag. Just looking at the drag, suction created by oil between the friction and steel plates appears to be the first place to look. The plates are not freely separating resulting in the Ďclunkí, especially from neutral into first.
Dimpled steel plates, as has been noted, address this suction. To decrease this suction and encourage the release of the plates. But I have found no one who has said where these are to be found. Trade secret. I did read on some forum for Japanese bikes that there can be uneven wear because when the steels are dimpled, internal stress is introduced which slightly warps, takes out of true, the steel. How much of an issue this is, i couldnít tell.
I was sitting looking at my beautiful K13R beast. It sits there waiting with itís offering of an addicting experience. Looking at the front disk brakes it occurred to me there is a steel plate with friction material that applies pressure. The disk is full of holes that the friction material rides over. I looked very carefully at the holes to see if the edges were relieved. No, all is just very flat. So the wear on the friction material by these holes must be minimal in relation to what the holes have to offer. Granted the friction material is substancial. But thinking about the clutch, I wondered if there might be a way of applying this idea. Not with holes, way too much work and possibly introducing dimensional changes, but cutting a fine groove. This groove could provide relief of the suction. It would pass between each friction pad. This groove would be slightly eccentric on the steel. The axis of this eccentric groove would be offset by the height of a friction pad. This would create a groove that was at the outer edge of the facing friction pad on one side and travel around to the opposite side where it would be near the inner side of a facing pad. See my little line drawing where the red line is the groove.
This eccentric groove would sort of sweep across each friction pad, top to bottom or the other way around. As pressure is applied the oil would be encouraged to be swept off. But when pressure is released, the groove could counter the suction force. Decreasing the Ďclunkí?
I would like to go to my local shop and ask for an old steel to see if a groove could be cut. This could be done on the faceplate of my lathe. I have no idea how deep of a groove to try. If it can be cut, the edges would have to be totally relieved, polished, to minimize the introduce wear.
Any input, ideas, experience or comments would be welcome. Do you stair at your bike and wonder? The bait hanging out in front of me is every now and then going from neutral into first is a beautiful click!
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  #2  
Old 06-24-2018, 10:40 PM
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Re: A thought about clutch drag

I would semi-speculate that the steel plates are stamped out of sheet, dimpled if required, tempered, then surface ground to be flat and to have parallel sides. Holes and grooves create stress risers in metal especially in such a thin plate spinning up to 11,000 RPM. In the absence of circulation of oil (or air in the case of brakes or a dry clutch), holes and grooves could collect residue. Maybe the grooves should be in friction material if used. Beyond that, not being trained or educated in the subject, all I could offer would be pure speculation.
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  #3  
Old 06-25-2018, 03:42 AM
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Re: A thought about clutch drag

Cant remember on what forum i read it, but someone posted that these dimpled plates from suzuki will fit the K12-K13 clutch....

Havent tried it myself, but when the day comes that i have to open up the clutch cover i'll order a set....just to try them.
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Old 06-25-2018, 04:48 AM
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Re: A thought about clutch drag

Behold, the mythical dimpled steels! Thank you Patrique.
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Old 06-25-2018, 06:53 AM
paulmogs paulmogs is offline
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Re: A thought about clutch drag

Quote:
Originally Posted by Patrique83
Cant remember on what forum i read it, but someone posted that these dimpled plates from suzuki will fit the K12-K13 clutch....

Havent tried it myself, but when the day comes that i have to open up the clutch cover i'll order a set....just to try them.

Appear to be 2001-2004 GSX-R1000 Suzuki. Handy to know thanks Patrique.
Suzuki part# 21451-40F00
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  #6  
Old 06-25-2018, 07:28 AM
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Re: A thought about clutch drag

I also see these fit;

2003 GSX R1000Z
2004 GSX R1000Z
2017GSX S1000FAL7
ď S1000L7
ď S1000A7

I just found a set of nine on EBay for $55 Canadian, thatís about $10 US! Three more than I need, into the parts department.
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  #7  
Old 06-26-2018, 12:18 AM
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Re: A thought about clutch drag

Now all we need to find are suitable springs and rivets..
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  #8  
Old 06-26-2018, 12:35 AM
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Re: A thought about clutch drag

I was looking at the parts diagrams for the oil pump. There were two different part numbers for the oil pump sprocket. It seems up until 09/2010 the sprocket has 25 teeth. After 09/2010 they added one tooth to make 26 teeth. Both had the two dogs to drive it. This extra tooth would increase the speed of the oil pump, therefore more oil pressure. Was this done to deliver a bit more oil to the clutch? If so, is this something one would consider changing while the clutch is out?
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  #9  
Old 06-26-2018, 05:04 PM
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Re: A thought about clutch drag

Quote:
Originally Posted by Scarecrow
$55 Canadian, thatís about $10 US!

That's not a favorable exchange rate.
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  #10  
Old 06-26-2018, 05:15 PM
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Re: A thought about clutch drag

Quote:
Originally Posted by Scarecrow
I was looking at the parts diagrams for the oil pump. There were two different part numbers for the oil pump sprocket. It seems up until 09/2010 the sprocket has 25 teeth. After 09/2010 they added one tooth to make 26 teeth. Both had the two dogs to drive it. This extra tooth would increase the speed of the oil pump, therefore more oil pressure. Was this done to deliver a bit more oil to the clutch? If so, is this something one would consider changing while the clutch is out?

There was also a change in the oil pump. Any change in oil pressure due to a change in pump RPM would be an assumption.
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Old 06-26-2018, 06:19 PM
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Re: A thought about clutch drag

You are right, it is an assumption based on what has been an ongoing low oil delivery problem. What do you know about the change in the oil pump? Did it happen around the same time this sprocket was changed? What insight might you have?
Yes, in and of itself, it may be of little consequence. Your explanation of error stacking, the idea that cumulative small issues can collectively lead to an unintended expression, could have a parallel with this clutch. Through the efforts of many, on this forum and else where, have not found a singular solution. But there do seem to be a number of Šreas where incremental improvement has been found. Addressing as many as is feasible might lead to a point where the hammer is not whacking the transmission when going from neutral into first.
The exchange rate might be a bit of an exaggeration. But the stronger American dollar is not going to help Trump trying to balance trade. Some inflation might shift the numbers.
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Old 06-26-2018, 10:26 PM
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Re: A thought about clutch drag

Quote:
Originally Posted by Scarecrow
You are right, it is an assumption based on what has been an ongoing low oil delivery problem. What do you know about the change in the oil pump? Did it happen around the same time this sprocket was changed? What insight might you have?
Yes, in and of itself, it may be of little consequence. Your explanation of error stacking, the idea that cumulative small issues can collectively lead to an unintended expression, could have a parallel with this clutch. Through the efforts of many, on this forum and else where, have not found a singular solution. But there do seem to be a number of Šreas where incremental improvement has been found. Addressing as many as is feasible might lead to a point where the hammer is not whacking the transmission when going from neutral into first.
The exchange rate might be a bit of an exaggeration. But the stronger American dollar is not going to help Trump trying to balance trade. Some inflation might shift the numbers.

The parts fiche lists two oil pumps. The application dates concur with the change of the sprocket(s). My insight is only the information readily available to all of us as published by BMW.

Error stacking was offered as an idea. I think of it as a low probability cruel act of fate. I offer no explanations as to the cause, effect or solution to the problem. There are much smarter members here that have devoted a lot of time and effort to this problem and have found some corrective actions. I respect their findings and opinions. While I wish it wasn't there, I regard the irritating clunk in a BMW as something to live with. There are high mileage BMW's that clunk and are still perfectly operable.

The comment on exchange rate was offered in humor. I will not make the mistake of offering that to your posts again. You should know that most here have the wisdom to avoid political comments as being counterproductive to the discussion of the K1300S.

Good luck in your future efforts.
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  #13  
Old 06-27-2018, 01:04 AM
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Re: A thought about clutch drag

Yes, written humor can hit a wall, especially with strangers. What might be a playful aspect of personality can not always be read through just words. There are no visual clues as to the intent. I did take your comment in jest and responded with it might be a bit of an exaggeration. But like me, you had no other clues as to my intent. And Iím sorry you took what I consider very basic economics, the exchange rate, as political. A currency that rises in value in relation to others, results in lower sales outside of that county, exports suffer. Inflation counters this and can make goods more attractively priced to importing countries. I should have left the current authors name out. Even with humor in mind I will remember to edit myself in any communication, until we are more familiar.

The error stacking, as an idea, intrigued me. I find those kind of concepts very interesting. The basic idea could be applied in what I suspect are many situations, not specifically our mechanical beasts. I did not mean to tie you to this idea being a possible answer to the issues surrounding this clutch. But you being the first person I have heard talk of this, I wanted to give you credit. It may be old hat to you and others but not for me.

I agree that many just live with the perceived issue and are OK with it. I have had this bike for just six months. At this point I am enjoying all I am learning as a result of looking into the quirks. In the end I may abandon the search. But for now, the new understanding about this bike adds to my enjoyment of it.

I see those little cartoon emojis as something to consider using.
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Old 06-27-2018, 01:57 AM
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Re: A thought about clutch drag

Hi all
I spoke to an master technician at BMW and he said that the old oil pump was making 3.5 bar and the new one 4.5 bar.If its true i would know.
Best of luck, i enjoy reading this sort of posts.
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Old 06-27-2018, 09:27 PM
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Re: A thought about clutch drag

I went to a motorcycle salvager and pick up a steel clutch plate. It is a bit less than 1/16Ē thick and dimpled. The dimpling creates small square recesses. These telegraph through the plate where they are slight bumps on the opposite side. Each side of the plate then has a surface of indents and bumps.

These plates are stamped from sheet material. One side has a slight round over edge, seen especially on the inner Ďteethí. The opposite side has crisp edges. These edges suggest no further treatment like surface grinding. The steel itself seems relatively soft, meaning not a high r factor. I can distort this plate by hand. I didnít choose this dimpled steel, it was all they had.

I put the steel on the face plate for the lathe. It was placed off centre by about 3/8Ē. Before I had this steel I had no idea of how hard this steel might be. Well, the cutter made short work in cutting a fine grove. On the opposite side of the steel the path of the grove is the reverse, close to the edge on one face and near the inner edge on the other. There are only two points where the opposing grooves cross each other. That point is midway in the path from the outside to the inside. The most metal is on each side of both grooves for best support. Some 1000 emery took care of a sight burr on the edge of the groove. I could take it to the buffer with some compound for a final cleanup.

The idea is the oil would be swept off the friction plate as pressure is applied. Because applied pressure is not instantaneous, oil is moved to the outside of the plate. The path of the groove over the friction material is from one side to the other. Wear of the friction pads caused by the groove is spread over the entirety. When pressure is released, the groove would weaken the suction. And maybe, just maybe lessen the clutch drag. In a wet clutch the oil is suppose to wash away the a braided material.

Of course this is a complete shot in the dark for me. I make no presumption that I am the first to consider this. I have not come across any description akin to this, maybe for good reason! But I have the time and capabilities as well as the curiosity to try. I have a new Barnett set of plates. So I will try this grooving on the steels in the clutch, the originals. If it turns out to be an exercise in futility, in go the new plates. I also took a gamble and ordered the dimpled Suzuki steels Patrique Hofmann noted were said to be compatible. All comments are welcome.
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Old 06-27-2018, 09:42 PM
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Re: A thought about clutch drag

perhaps sites use stock images but used plates on ebay would seem to strongly indicate that there is a profound difference on the shape of the splines meaning the Suzuki plates will not fit.
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Old 06-27-2018, 09:51 PM
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Re: A thought about clutch drag

Like I said, I feel itís a bite of a gamble. They were new in the package and at a price Iím willing to play with. I have found Patriqueís videos and coments very informative. So there is goodwill on my side and he did state he has not tried them yet. Computable steels are out there, that we know, just need confirmation.
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Old 06-27-2018, 10:16 PM
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Re: A thought about clutch drag

Quote:
Originally Posted by WPV
The parts fiche lists two oil pumps. The application dates concur with the change of the sprocket(s). My insight is only the information readily available to all of us as published by BMW.

Error stacking was offered as an idea. I think of it as a low probability cruel act of fate. I offer no explanations as to the cause, effect or solution to the problem. There are much smarter members here that have devoted a lot of time and effort to this problem and have found some corrective actions. I respect their findings and opinions. While I wish it wasn't there, I regard the irritating clunk in a BMW as something to live with. There are high mileage BMW's that clunk and are still perfectly operable.

The comment on exchange rate was offered in humor. I will not make the mistake of offering that to your posts again. You should know that most here have the wisdom to avoid political comments as being counterproductive to the discussion of the K1300S.

Good luck in your future efforts.


Few motorcycles I have driven have zero clunk, Its possibly a fucntionof design made worse with wear. I doubt it can be gotten rid of.
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Old 06-28-2018, 02:21 AM
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Re: A thought about clutch drag

You can't eliminate the clunk - there has to be some relative motion between the driving and driven plates, even at idle in neutral, otherwise the gears couldn't engage (motorbike gearboxes are not synchronous like car ones are).

To answer your question re where to obtain dimpled plates, you need to go to the one place you have not yet tried - BMW. The clutch plates on my 2014 K1300S are dimpled, as should any new clutch plates be. And itís not the magic cure you are hoping for - my clunk is as big as it gets!

I have tried a 2009 clutch basket and plates, another from 2012, both with their old bearings and updated bearings. None of this made any appreciable difference to the clunk, in fact Iím sure the clunk was better with the old bearing (obviously the engine runs smoother with the new bearing though).


Steve
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Old 06-28-2018, 01:07 PM
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Re: A thought about clutch drag

Hi Steve. Itís a bit discouraging to hear of your results. There are two areas with issues, noise/vibration and the clutch function. I donít think those that dealt with the noise/vibration noticed any significant difference in the clutch.

I do appreciate your comment about the need for a speed difference between the driven plate and the driving plate. Without this difference, gear alignment for meshing would be hit and miss. The rotational difference will produce a noise as the gears find proper meshing. So the bigger the difference the more noticeable the engagement will be, clunk. They all do it, itís a matter of minimizing this difference short of zero.

Here is what wrinkles my brow, the bike is idling, i pull in the clutch and shift into first, thwack. Stationary and still in first gear with the clutch still pulled in, i shift into second gear, just a click. Still holding the clutch in, I shift back into first, just a click. The clutch is the go between the power and the drive. Why the difference? Both have the clutch pulled in while shifting into first from neutral. There is something about those plates. They need to separate or slide past one another with minimal resistance when not under pressure. The maximum distance between plates is created by the clutch slave cylinder. The slipping past each other is the job of the oil. A last observation, with the clutch pulled in while moving through second, neutral and back into first. The longer the pause while in neutral before going into first, the closer the clunk returns to what it was straight from start into first. The sticky ness between plates seems to progressively return.

To me, going between gears with the clutch pulled in, says this clutch is capable of what is within customary expectations. Why doesnít it do this from idle, pulling the clutch in and engaging first gear? There seems to be the needed space indicated by the ease of moving between the gears with the clutch pulled. From all the exploring others have done along with the changes, the amount of oil delivered to the plates seems to be adequate. So this leaves me looking at the plates sticking to each other.

Yesterday I came across a PDF file for a German company that makes clutch plates. The icons depicting the intended end use went from motorcycles, aircraft to battle tanks. Their focus is on the surface of the friction and steels. There is a large range of cut or grooved patterns on the friction plates, even a spiral. The steels were not illustrated, but grooving is mentioned. So addressing the ability for the plates to separate goes well beyond dimples and a carbon Barnett.

Google Ďfriction lining and steel platesí a PDF file connected to NB Parts. I believe much of what they offer is custom to manufacturers.
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Old 06-28-2018, 01:44 PM
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Re: A thought about clutch drag

I think you are overthinking. The verbosity of your posts would seem to indicate that.
I bike will clunk cold going up into 2nd if it is the initial shift. This is perhaps more of an issue with fluid dynamics than any foible remedied by an esoteric clutch plate.
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Old 06-28-2018, 04:46 PM
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Re: A thought about clutch drag

Kafka

My bike will also clunk if the initial shift is into second. That is not through my verbosity what I was noting. Initial shift into any gear creates a clunk hot or cold on my bike. It is the second shift, not having released the clutch, that is just a click. I have gone into first with the attendant clunk, still not having released the clutch, I shift into second with no clunk. This is with the bike stationary. Something has happened with the plates. My guess is the plates moving in mass together was interrupted by going into first. This hints that the clutch is capable of a less intrusive hammer to the tranny when initially going into first gear.

Iím not preaching that I have the answer. But I am asking questions based on what Iíve observed. This is a man made object, not a spiritual subject where asking why will really result in no definitive answer. Cause and effect, I realize the input to cause can be great. But why should that preclude or discourage examination?

I might also note that my bike is a 2009 K13R that had 5200 kilometres on it when I got it in December. Not old and worn out. This is the first year of the 1300ís. BMW continued to tweak things through the years. Like was just pointed out, the later clutches have dimpled steels. So the clunk Iím referring to may be less noticeable with later bikes.
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Old 06-28-2018, 04:55 PM
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Re: A thought about clutch drag

Kafka

Could you share your expressed thoughts about the clutch and fluid dynamics? Iím interested.
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Old 06-29-2018, 11:53 AM
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Re: A thought about clutch drag

If anyone is interested, here is a companies web address that specializes in clutch plates. It goes well beyond a steel and padded friction plates. Both plates are engineered around heat and especially the oil environment they are expected to function in. From a splashing sump to a minimal mist of oil.

Iím not saying any of these patterns are the answer to the clunk. But looking at what has been developed for some extreme conditions, like the torque of a battle tank, illustrates there are approaches to a great many issue a clutch is required to deal with.

https://loganclutch.com/clutch-discs-product
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Old 07-02-2018, 05:19 AM
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Re: A thought about clutch drag

Quote:
Originally Posted by Scarecrow

I put the steel on the face plate for the lathe. It was placed off centre by about 3/8”. Before I had this steel I had no idea of how hard this steel might be. Well, the cutter made short work in cutting a fine grove. On the opposite side of the steel the path of the grove is the reverse, close to the edge on one face and near the inner edge on the other. There are only two points where the opposing grooves cross each other. That point is midway in the path from the outside to the inside. The most metal is on each side of both grooves for best support. Some 1000 emery took care of a sight burr on the edge of the groove. I could take it to the buffer with some compound for a final cleanup.


I wonder if these these excentric grooves will hurt the balance of the clutch assembly as a whole?
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Old 07-02-2018, 09:58 AM
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Re: A thought about clutch drag

Balance, it is worth considering. WPV spoke of error stacking. With seven steels, take a common reference point in the groove, such as closest to the edge, and place each plate evenly around 360 deg. With X-ray vision it would look like a flower and avoid error stacking.

Thatís with just one eccentric groove on a steel. But a second groove on the other side cut just the reverse, what was near the edge on one side is now the inner on the opposite, would balance it.

This eccentric groove is a simplistic idea. In the industrial world of clutch plates, grooving has and is very considered. What Iím interested in seeing is, can this reduce enough of the suction force between plates, freeing the plates with less force, therefore less clunk? The eccentric groove is not magic. Itís just something I can do myself. An eccentric groove is also the simplest groove for even wear on the friction material as it rotates passed. Oil can be pushed and flung out of the groove between the pads.

Another possible contributor to clutch drag is the amount of space created when the clutch is pulled in. I did come across a member that was having trouble with clutch slippage. Turned out the flat part of the ball in the slave cylinder was not facing the thrust adapter. The difference in the starting point of that thrust adapter was now about 4 mm closer to the clutch assembly. Some of the pressure within the clutch pack was released. Only slippage was mentioned. I have written asking him if he noticed any difference when going from neutral into first. Havenít heard back yet.
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Old 07-04-2018, 08:46 PM
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Re: A thought about clutch drag

I had thought the amount of oil delivered to the clutch plates was sort of settled. The long thrust adapter with the two grooves, once introduced, went unchanged to the end. But as WPV pointed out there was the introduction of a new oil pump. It was first on the parts list for the 2011 run. Although it was included in the later 2010 models. This new pump, Z-24/5.5 bar, has one less tooth on the pump gear and produces 1 bar more pressure. That is a 25% increase in pressure, not insignificant.

My question is, has anyone experienced both and noted any differences in the clutch behaviour? My bike is a 2009 K13R which has the same oil pump used in the k1200ís, Z-25/4.5 bar.
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Old 07-05-2018, 12:33 AM
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Re: A thought about clutch drag

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Old 07-05-2018, 02:54 AM
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Re: A thought about clutch drag

Quote:
Originally Posted by Scarecrow
I had thought the amount of oil delivered to the clutch plates was sort of settled. The long thrust adapter with the two grooves, once introduced, went unchanged to the end. But as WPV pointed out there was the introduction of a new oil pump. It was first on the parts list for the 2011 run. Although it was included in the later 2010 models. This new pump, Z-24/5.5 bar, has one less tooth on the pump gear and produces 1 bar more pressure. That is a 25% increase in pressure, not insignificant.

My question is, has anyone experienced both and noted any differences in the clutch behaviour? My bike is a 2009 K13R which has the same oil pump used in the k1200ís, Z-25/4.5 bar.
What's the partnumber on the new pump?

Looke'd at realoem and only found the 4,5 bar pump.
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Old 07-05-2018, 03:08 AM
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Re: A thought about clutch drag

new oil pump

https://www.realoem.com/bmw/enUS/sho...diagId=11_4272
old oil pump
https://www.realoem.com/bmw/enUS/sho...diagId=11_4272
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Old 07-05-2018, 07:26 AM
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Re: A thought about clutch drag

Had a look at my spare clutch and oil pump that i have sitting on shelf....
Both came out from a 2011 K1300r.
Pump has 25 teeth
Clutch Sprocket has 25 teeth.
Another weird thing is, that the pumphousing has a manufacturing stamp of 07 and 06.

So somehow the "realoem" dates are not correct as to when the 5.5 pump was being fitted. Clearly not in 2011....

I did some research a while ago on this topic too (4.5 vs 5.5) and i sort of remember that the 5.5 bar pump was introduced after 2014.....
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Old 07-05-2018, 07:54 AM
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Re: A thought about clutch drag

Much work to swap out the pumps??
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Old 07-05-2018, 08:04 AM
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Re: A thought about clutch drag

Quote:
Originally Posted by Patrique83
Had a look at my spare clutch and oil pump that i have sitting on shelf....
Both came out from a 2011 K1300r.
Pump has 25 teeth
Clutch Sprocket has 25 teeth.
Another weird thing is, that the pumphousing has a manufacturing stamp of 07 and 06.


Have You tried on realoem with Your vin code (last 7 frame's digits) to check what is indicated? (25 or 26 teeth).
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Old 07-05-2018, 08:28 AM
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Re: A thought about clutch drag

I came across the dates on bmwautoparts.net. 2010 is the last year with the 4.5. The 5.5 is listed as the pump from 2011 on. They seem to have it down to the month with Ďtill 10-09í for Z-25/4.4 bar or Ďfrom 10-09í for Z-24/5.5 bar. So Patrique, maybe the paper work is more organized than the assembly!

11 41 7 678 485
11 41 8 502 234
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Old 07-05-2018, 08:33 AM
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Re: A thought about clutch drag

@Matthias: The exhaust system has to come off to remove the Oil Pan to get to the oil pump. And the clutch and clutch basket needs to come out to get to the oil pump drive sprocket so you can replace it.
So quite a bit of work there.... plus gaskets and aluminum bolts.

@VM5: I have a 2005 K1200s..... no need to check on that.

The parts were from a dealer in the USA. And he did have a VIN number attached to the part when he shipped it to me. It was a 2011 K1300r
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Old 07-05-2018, 01:19 PM
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Re: A thought about clutch drag

Quote:
Originally Posted by vm5
Have You tried on realoem with Your vin code (last 7 frame's digits) to check what is indicated? (25 or 26 teeth).
Thanks for the email!!
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Old 07-06-2018, 08:24 PM
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Re: A thought about clutch drag

I just opened up the clutch today. This is what I found. Not like my K12R. A friction plate is one space over from the rest of the pack. This plate is the one with the Belleville washer. Yes it fit, but a little more snug than the others. Is this right? There seemed to be lots of oil throughout. I also noticed that this particular plate had manufactured hatching in the friction pads that faced the pressure plate. The other side was plain as were all the rest of the plates.
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Old 07-06-2018, 09:10 PM
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Re: A thought about clutch drag

Scarecrow, there are plenty of posts on here about this. Try searching for something like K1300 clutch rebuild.

I have a 2008 K1200GT that at 20k the clutch started becoming rough and uneven.
Mine had the old style throw out bearing not allowing as much oil to pass as the K13 version and the end friction plates were completely worn while the middle ones looked like new.
I sent the assembly into John Sykes in the UK to rebuild it with dimpled plates and additional holes drilled in the hope in order to allow more oil to pass through, then I purchased from BMW the stock through out bearing for the K13 models that has an extra notch cut in it to allow more oil to flow.

Since then, this is what I noticed. My clunk is louder to 1st and finding neutral is harder when the clutch/engine is hot. This happens only when I’m sitting in traffic as I live in a big city.
My clutch feel and everything is VERY smooth, probably better than new. But What I noticed (with the help from YouTube videos that John posted) is that the oil only runs through the shaft and into the clutch ONLY when the rear wheel is in motion. This means that sitting at a light idling does not mean that oil is being sprayed into the clutch basket. Regardless of all of this if I come to a stop and wait there with the bike in neutral vs 1st with the handle pulled, the clunk tends not to be as loud as if I sat there with the handle pulled then out it in neutral and back again.

I’m not sure what this is telling me, other than maybe the spinning of the clutch assembly at a stop sitting on neutral causes heat to dissipate.
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Old 07-07-2018, 01:12 AM
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Re: A thought about clutch drag

Looking on line, I see this offset of the last or first, depending on how you look at it, is normal. I do not remember this on my 06 K12R clutch. I will groove the originals and keep the Barnettís in reserve if I mess up!
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Old 07-07-2018, 08:26 AM
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Talking Re: A thought about clutch drag

@petemw

Here is why it clonks going from neutral into 1st gear:

Engine crankshaft drives the clutch basket and friction plates (both are always spinning)

The gearbox input shaft is driven by the clutch steel plates.

Now, if you pull the clutch lever and the bike is still in gear, the gearbox will hold the inputshaft/steel plates firmly in place (not spinning with the rest of the clutch).

When you shift into "N" and release the clutch lever, the input shaft+steelplates+friction plates will all start moving as one unit now, because the gearbox is not holding the input shaft in place anymore (being in neutral).

Now you pull the clutch lever again, putting it into 1st gear.....
****CLONK*****
The transmission input shaft and steelplates are spinning at nearly the same speed as the crankshaft and now come to a complete stop (1st gear is holding the shaft again).
The entire momentum of the gearbox input shaft+steel plates comeing to a stop is dampened by the rear driveshaft and partially by the dampening springs of the basket.
Some of the backlash goes into the basket springs because the steel plates stick to the friction plates until they seperate.

The dimpled plates are supposed to reduce the "stickiness" of the steel plates to the friction plates.

I hope this makes sense..... because its quite difficult to visualize all the moving components if you havent been that derp into the motor/clutch/gearbox....
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Old 07-07-2018, 11:10 AM
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Re: A thought about clutch drag

Patrique, itís well explained. I read a review of the K13R from 2009 where they noted some of the design changes from the K12. One of those was the multi compound drive shaft. You just made the connection to a reason why.

Yesterday I put the K13 on the service stand, back wheel off the ground. Started the bike in neutral. The rear wheel just move a little. If I rotated the wheel forward, it rolled easily as if it had the most perfect bearings. Pushing the wheel in the other direction and it stopped almost immediately. Pulling the clutch in and dropping into first, the wheel started rapidly spinning, clutch still in. I then tried this on my R12R and it never really moved when I repeated what I had just done with the K. I understand there is a clutch difference, single plate.

In this mucking about clutch in, clutch out, in neutral, in first......., what I found interesting was around neutral. With clutch in, dropping into first with the clonk. Clutch still in shifting into second is just a click. Clutch still in, go from second into neutral. If I continue into first no clonk. Here is the tell, the longer I pause in neutral the more pronounced the clonk becomes. The plates which were disengaged are being spun up again, stickiness, clutch drag. From my understanding, both air, meaning lack of, and a liquid can create drag when two smooth surfaces are pressed together. So this spin up in neutral indicates torsion drag. From what Iíve been reading this can happen from too little oil, too much oil and or too little space for the plates to separate. Oil viscosity also has a say, but I will go with BMWís 5/40.

The concern with the amount of oil delivered to the clutch is part of these bikes history. Taking my clutch out yesterday I saw all the steels coated with oil. Start from the point where we say the amount of oil being delivered should be adequate. The suggestion then is the film of oils Ďadhesioní properties are greater than the forces that would separate the plates. Because the centripetal force is constantly moving the oil out of the space between plates, this indicates there is a supply of oil coming from the inside to maintain this drag/stickiness. So the oil needs to drain between the plates faster than itís replaced.

The other way to deal with this film of oil is to increase its thickness, not viscosity but depth. As this film increases in depth the less force it takes to separate. Hence, dimpled plates. Those little dents and bumps increase the thickness of the oil film which weaken its tensile strength. Grooving is more dramatic but addresses both oil drainage and weakening of the oils tensile strength.

Today I start cutting my simplistic grooves. Finally heís talking practically!
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Old 07-07-2018, 11:13 AM
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Re: A thought about clutch drag

Patrique, thanks for the explanation, makes total sense!
I did play around when I had it open and realized this basic movement between parts...but when I did have it open I also observed that the entire assembly before the final drive exchange to rear wheel is quite tight. Meaning that I donít suspect much Ďclunkí to come from these moving parts besides what you described and the basket springs. This leads me to believe that the majority of Ďclunkí comes from the extra play in the final drive. It doesnít bother me much other than thinking every time I do it that Iím slowly damaging linkages and the like.
Thoughts?
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Old 07-07-2018, 11:27 AM
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Re: A thought about clutch drag

Good Luck!, let us know how it goes. My OEM (original) plates had overheated oil goo all over them indicating overheating and, like you say, the oil not being flung off fast enough. This is an interesting point you mention as it would answer why it runs smoother letting the basket spin, in Neutral with clutch engaged. This would provide centrifugal force effectively cleaning the assembly of old overheated oil.

Quote:
Originally Posted by Scarecrow
Patrique, itís well explained. I read a review of the K13R from 2009 where they noted some of the design changes from the K12. One of those was the multi compound drive shaft. You just made the connection to a reason why.

Yesterday I put the K13 on the service stand, back wheel off the ground. Started the bike in neutral. The rear wheel just move a little. If I rotated the wheel forward, it rolled easily as if it had the most perfect bearings. Pushing the wheel in the other direction and it stopped almost immediately. Pulling the clutch in and dropping into first, the wheel started rapidly spinning, clutch still in. I then tried this on my R12R and it never really moved when I repeated what I had just done with the K. I understand there is a clutch difference, single plate.

In this mucking about clutch in, clutch out, in neutral, in first......., what I found interesting was around neutral. With clutch in, dropping into first with the clonk. Clutch still in shifting into second is just a click. Clutch still in, go from second into neutral. If I continue into first no clonk. Here is the tell, the longer I pause in neutral the more pronounced the clonk becomes. The plates which were disengaged are being spun up again, stickiness, clutch drag. From my understanding, both air, meaning lack of, and a liquid can create drag when two smooth surfaces are pressed together. So this spin up in neutral indicates torsion drag. From what Iíve been reading this can happen from too little oil, too much oil and or too little space for the plates to separate. Oil viscosity also has a say, but I will go with BMWís 5/40.

The concern with the amount of oil delivered to the clutch is part of these bikes history. Taking my clutch out yesterday I saw all the steels coated with oil. Start from the point where we say the amount of oil being delivered should be adequate. The suggestion then is the film of oils Ďadhesioní properties are greater than the forces that would separate the plates. Because the centripetal force is constantly moving the oil out of the space between plates, this indicates there is a supply of oil coming from the inside to maintain this drag/stickiness. So the oil needs to drain between the plates faster than itís replaced.

The other way to deal with this film of oil is to increase its thickness, not viscosity but depth. As this film increases in depth the less force it takes to separate. Hence, dimpled plates. Those little dents and bumps increase the thickness of the oil film which weaken its tensile strength. Grooving is more dramatic but addresses both oil drainage and weakening of the oils tensile strength.

Today I start cutting my simplistic grooves. Finally heís talking practically!
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Old 07-07-2018, 06:55 PM
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Re: A thought about clutch drag

The clonk sound comes from inside the gearbox, when the spinning input shaft hits the stationary (1st) gear.....

There is only minor play between final drive / drive shaft / 90* angle gearbox outlet / gear assembly (1-6).

You are correct, the clonk is worse between K12 and K13 because the K12 driveshaft is less flexible/less dampening....

I installed a K13 shaft into my K12 and the clonk has become noticeably less, compareable to the K13....


Here is something to try, which can lessen the effect of stickiness of the plates before putting it into 1st gear:

Pull clutch, rev the bike to 5000-6000 for a second or two, now back to idle....
This will cause the friction and steel plates to de-stick.
The clonk should be noticeably less now putting it into gear.
Works on mine.... its just not practical for everday use.
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Old 07-07-2018, 09:20 PM
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Re: A thought about clutch drag

Yes, if I press into 1st slowly, I can hear the clack clack clack as the gears try to mesh. Again illustrating what a factor clutch drag is. Iím loosing my hair and itís not genetic! I read somewhere that very little is completely original. Itís more about removing the negatives, real or perceived. I have yet to try getting off and running around the bike three times.
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Old 07-07-2018, 09:32 PM
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Re: A thought about clutch drag

For those that might be interested in an academic study of clutch drag. These are extracts from an automotive engineers thesis for his masters degree. The vast majority was well beyond me. But I did find interesting nuggets between the equations. It is only those nuggets I include. Because these have been taken out of context, note, loss refers to loss of torque due to drag.

In the two thesis i came across, dealing with drag came down to economics. Over the life time of large equipment, the added fuel cost due to drag is considered significant.

From a practical point, this doesnít provide an answer to the K-Clunk. What it does speak to are the points that contribute to drag. Along with these points are the principles of the dynamics at play. I include, in the remote case someone might want to see this document, the front cover to google.
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Old 07-08-2018, 12:37 AM
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Re: A thought about clutch drag

Thanks for sharing those excerpts.
While out today riding I was contemplating all of this and then I noticed something, possibly new, possibly not.

Hereís the scenario, Cruising in 1st around 20mph and come to a complete stop by coasting with the clutch disengaged. Once almost stopped or stopped there is a similar clunk but not as loud heard. The same sound isnít heard again until the next stop. If everything is tight in the transmission case and engine then what is ďdroppingí or clunking upon a stop like this? It seems to be something thatís under load until the speed is low enough for that load to reduce and something mechanical to relax.
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Old 07-08-2018, 02:09 AM
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Re: A thought about clutch drag

Patrique might have an idea about what you noticed. I have notice before starting the bike when I roll it out of the garage, there can be this quiet thunk. If I rock the bike back and forth while in gear itís there. Iíve thought itís lash in the transmission and or drive shaft. I think itís like the tolerances in a gear when put under load and the reversing the direction. There is a slap as whatever tolerance was present is swung to the other side of the gear tooth. Speculation on my part.
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Old 07-11-2018, 06:09 AM
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Re: A thought about clutch drag

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Iím no engineer nor am I a mechanic. But this clutch drag resulting in that Ďclunkí is occupying my thoughts. Iím very aware many fine minds have been looking into this. This forum is a clearing house for ideas with an impressive worldwide array of contributors.
There seem to be many issues that contribute, on their own or some combination, to this drag. Just looking at the drag, suction created by oil between the friction and steel plates appears to be the first place to look. The plates are not freely separating resulting in the Ďclunkí, especially from neutral into first.
Dimpled steel plates, as has been noted, address this suction. To decrease this suction and encourage the release of the plates. But I have found no one who has said where these are to be found. Trade secret. I did read on some forum for Japanese bikes that there can be uneven wear because when the steels are dimpled, internal stress is introduced which slightly warps, takes out of true, the steel. How much of an issue this is, i couldnít tell.
I was sitting looking at my beautiful K13R beast. It sits there waiting with itís offering of an addicting experience. Looking at the front disk brakes it occurred to me there is a steel plate with friction material that applies pressure. The disk is full of holes that the friction material rides over. I looked very carefully at the holes to see if the edges were relieved. No, all is just very flat. So the wear on the friction material by these holes must be minimal in relation to what the holes have to offer. Granted the friction material is substancial. But thinking about the clutch, I wondered if there might be a way of applying this idea. Not with holes, way too much work and possibly introducing dimensional changes, but cutting a fine groove. This groove could provide relief of the suction. It would pass between each friction pad. This groove would be slightly eccentric on the steel. The axis of this eccentric groove would be offset by the height of a friction pad. This would create a groove that was at the outer edge of the facing friction pad on one side and travel around to the opposite side where it would be near the inner side of a facing pad. See my little line drawing where the red line is the groove.
This eccentric groove would sort of sweep across each friction pad, top to bottom or the other way around. As pressure is applied the oil would be encouraged to be swept off. But when pressure is released, the groove could counter the suction force. Decreasing the Ďclunkí?
I would like to go to my local shop and ask for an old steel to see if a groove could be cut. This could be done on the faceplate of my lathe. I have no idea how deep of a groove to try. If it can be cut, the edges would have to be totally relieved, polished, to minimize the introduce wear.
Any input, ideas, experience or comments would be welcome. Do you stair at your bike and wonder? The bait hanging out in front of me is every now and then going from neutral into first is a beautiful click!

To eliminate clutch drag and improve the clutch action all you have to do is fit a Barnett clutch pack and remove and discard the anti judder belville and backer, this allows the plates to separate about 50% further than with the BMW set up and allows for a noiseless selection of first gear, even when hot.
The clutch facing on the Barnett plates automatically eliminates judder and sqwauk (unlike the standard BMW parts) and does not need the problematical belville ring.
Cost is under £100 and is the best money I ever spent on my K
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Old 07-11-2018, 06:13 AM
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Re: A thought about clutch drag

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Originally Posted by Scarecrow
I was looking at the parts diagrams for the oil pump. There were two different part numbers for the oil pump sprocket. It seems up until 09/2010 the sprocket has 25 teeth. After 09/2010 they added one tooth to make 26 teeth. Both had the two dogs to drive it. This extra tooth would increase the speed of the oil pump, therefore more oil pressure. Was this done to deliver a bit more oil to the clutch? If so, is this something one would consider changing while the clutch is out?

The smaller sprocket is driven by 6 pins, the larger by two. There isnít enough chain adjustment to fit the larger sprocket but if ever the engine were apart it would be a good idea but you will need a new primary gear to drive it.
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Old 07-11-2018, 08:08 AM
Dirk C Dirk C is offline
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Re: A thought about clutch drag

Hi Bengard would you mind taking picture of the anti judder belville and backer you are talking about, i have two clutch pack's at home and no clue what the belville and backer look like?
I'm thinking of buying a k13 again and wants to know if its possible to fix this issue without spending to much money.
Thanks in advance for the pictures.
Best Regards.
Dirk.
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  #52  
Old 07-11-2018, 09:15 AM
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petemw petemw is offline
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Re: A thought about clutch drag

This thread has all the info you need re: our clutches.

http://www.i-bmw.com/showthread.php?t=51004&page=4

Quote:
Originally Posted by Dirk C
Hi Bengard would you mind taking picture of the anti judder belville and backer you are talking about, i have two clutch pack's at home and no clue what the belville and backer look like?
I'm thinking of buying a k13 again and wants to know if its possible to fix this issue without spending to much money.
Thanks in advance for the pictures.
Best Regards.
Dirk.
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2008 K1200GT Dark Graphite Metallic
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  #53  
Old 07-11-2018, 09:47 AM
vm5 vm5 is offline
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Re: A thought about clutch drag

http://www.i-bmw.com/showpost.php?p=705351&postcount=96
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  #54  
Old 07-11-2018, 11:54 AM
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Scarecrow Scarecrow is offline
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Re: A thought about clutch drag

Bengarzy, Iím about to try the Barnettís today.

Iím putting aside the grooving of the steels for now. I did groove the original BMW steels. Went for a ride, lots of variety. Canít say I noticed any difference. Came home let the bike cool down and opened her up. The pack was virtually dry except for signs of oil on the outer most plates! Tinny bits of oil within the middle. So there is an oil problem.

I measured the location of all the oil holes in the hope. The outer and inner most plates have multiple holes. They were the ones wet with oil. Most of the other holes did not match up well with the friction plates. I stacked the Barnettís and measured to the centre of the friction plates. I drilled these hole 180 deg. to what seemed to be the intended hole. Still using the original BMW plates, I reinstalled and went for the same ride. The only difference was with the clutch pulled in, going from 1st into neutral and back into first. The pause in neutral with clutch still in could be a bit longer before the clunk returned to its normal thwack. Not waiting for the engine to cool down, I opened her up again.

Yes, I know the new holes were referenced differently. But I had one constant in the original plates. Out came the pack. Again the inner and outer plates were oiled. Interesting were the interior plates. One steel had oil on both sides and two had oil on only one side. An improvement, but erratic.

So today I will try the Barnettís that should line up with the holes. I was encouraged to see oil moving in the channels with multiple holes and getting to the furthest plate. One small change I made to the channels. Because of the casting, there is a rise in the middle. I filed those down and there is now a slight slope towards the pressure plate. With the forces involved, this probably will have little effect.

A last observation. There is an Oberon slave cylinder. Yesterday the small piston fell out and I notice the inner end had a circular dent, 1/2 to 1 mm in depth. This piston rides a bearing within the slave. If this is wear, does this lessen the space within the pack when the clutch is pulled in?
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  #55  
Old 07-11-2018, 05:00 PM
Bengarzy Bengarzy is offline
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Re: A thought about clutch drag

Quote:
Originally Posted by Dirk C
Hi Bengard would you mind taking picture of the anti judder belville and backer you are talking about, i have two clutch pack's at home and no clue what the belville and backer look like?
I'm thinking of buying a k13 again and wants to know if its possible to fix this issue without spending to much money.
Thanks in advance for the pictures.
Best Regards.
Dirk.
You canít miss it when stripped, the only narrow friction plate has the two components I speak of, a flat steel ring and a dished steel ring of the same diameter, together they make a compression spring that gives a progressive pick up of the clutch action but more importantly is responsible for the nasty clunk when engaging first, you wonít notice itís gone with the Barnett clutch pack as it has a nice progressive drive pick up because of the carbon material.
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  #56  
Old 07-11-2018, 05:08 PM
Bengarzy Bengarzy is offline
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Re: A thought about clutch drag

Quote:
Originally Posted by Scarecrow
Bengarzy, Iím about to try the Barnettís today.

Iím putting aside the grooving of the steels for now. I did groove the original BMW steels. Went for a ride, lots of variety. Canít say I noticed any difference. Came home let the bike cool down and opened her up. The pack was virtually dry except for signs of oil on the outer most plates! Tinny bits of oil within the middle. So there is an oil problem.

I measured the location of all the oil holes in the hope. The outer and inner most plates have multiple holes. They were the ones wet with oil. Most of the other holes did not match up well with the friction plates. I stacked the Barnettís and measured to the centre of the friction plates. I drilled these hole 180 deg. to what seemed to be the intended hole. Still using the original BMW plates, I reinstalled and went for the same ride. The only difference was with the clutch pulled in, going from 1st into neutral and back into first. The pause in neutral with clutch still in could be a bit longer before the clunk returned to its normal thwack. Not waiting for the engine to cool down, I opened her up again.

Yes, I know the new holes were referenced differently. But I had one constant in the original plates. Out came the pack. Again the inner and outer plates were oiled. Interesting were the interior plates. One steel had oil on both sides and two had oil on only one side. An improvement, but erratic.

So today I will try the Barnettís that should line up with the holes. I was encouraged to see oil moving in the channels with multiple holes and getting to the furthest plate. One small change I made to the channels. Because of the casting, there is a rise in the middle. I filed those down and there is now a slight slope towards the pressure plate. With the forces involved, this probably will have little effect.

A last observation. There is an Oberon slave cylinder. Yesterday the small piston fell out and I notice the inner end had a circular dent, 1/2 to 1 mm in depth. This piston rides a bearing within the slave. If this is wear, does this lessen the space within the pack when the clutch is pulled in?
The ball in the clutch slave cylinder piston has a ground flat on it (standard BMW slave).
If the after market slave cylinder has a bigger bore it will make the clutch lever lighter (better hydraulic leverage) but will also reduce the separation of the clutch pack (not good for smooth first gear engagement). This flat goes against the clutch push rod, apply sticky grease to keep it facing outwards.
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  #57  
Old 07-11-2018, 05:14 PM
Bengarzy Bengarzy is offline
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Re: A thought about clutch drag

Quote:
Originally Posted by Bengarzy
The ball in the clutch slave cylinder piston has a ground flat on it (standard BMW slave).
If the after market slave cylinder has a bigger bore it will make the clutch lever lighter (better hydraulic leverage) but will also reduce the separation of the clutch pack (not good for smooth first gear engagement). This flat goes against the clutch push rod, apply sticky grease to keep it facing outwards.
Also donít fret too much about the oil on the plates, a bit of a witch hunt really, the oil is flung through the clutch by centrifugal force and the clutch housing has no oil in it to speak of as it drains out the open lower half instantly.
The main problem with premature clutch wear is riders hold the clutch in to avoid the clunk and the clutch wears out at the lights 😂😂 I had zero wear on mine in 20,000 miles
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  #58  
Old 07-11-2018, 07:21 PM
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Scarecrow Scarecrow is offline
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Re: A thought about clutch drag

Bengarzy, I put the Barnett clutch plates in. The bike had been in 1st gear on the stand. With the stand removed, i pulled the clutch in. The motor was not running. As I rolled backward I felt resistance and could actually hear the clutch rotating. Moving forward, for the brief time it took for the lash to reestablish itself she rolled smoothly. Then the same resistance and clutch rotation sound. I put it up on the stand again and started the motor and put it into first. Big thwack. Massive drag.

So for the fourth time in about six days, I opened her up again to see if I had done something wrong. Removed the clutch pack and couldnít see anything unexpected. Put her all back together and nothing had changed. Thwack.

Iím starting to wonder about the slave cylinder. The pressure is just not coming off the plate pack. I did note there was a thickness difference in the original friction plates and the new Barnetts, wear. There was also a notable difference in the steels. I didnít record any of these measurements. So I sit frustrated staring at that slave cylinder.

That little piston in the slave I mentioned had a wear dent. I reversed this piston, it is symmetrical, when I reinstalled with the Barnetts the first time. Thinking this might help separate the plates not having the dent in. But even with a short operation of the motor, I could see a small spot developing. Can you enlighten me why the ability to separate the plates is reduced when hydrolic advantage is introduced?

I guess I should bleed the clutch system next. Any suggestions? OEM slave?
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  #59  
Old 07-11-2018, 09:32 PM
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Scarecrow Scarecrow is offline
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Re: A thought about clutch drag

Bengarzy, i think I get why less throw the wider the piston. A finite amount of fluid spread over a larger area. OK, the Oberon has a 36mm piston, the K1300 a 34mm and the K1200 a32mm. Would the K1200s slave produce the most separation.
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  #60  
Old 07-12-2018, 04:46 PM
Bengarzy Bengarzy is offline
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Re: A thought about clutch drag

Quote:
Originally Posted by Scarecrow
Bengarzy, i think I get why less throw the wider the piston. A finite amount of fluid spread over a larger area. OK, the Oberon has a 36mm piston, the K1300 a 34mm and the K1200 a32mm. Would the K1200s slave produce the most separation.

Yes, the smaller the slave (if master cylinder stays the same) the more separation will occur when the clutch lever is pulled in, the volume difference between32 and 36 is huge and the movement of the clutch release push rod will be about 30% or more down, fit the 32 mm one and bleed and see how much improvement you get, if the lever is not too heavy go with it, on the other hand if itís crippling try the standard 1300 34mm one.
The thickness of the plates is irrelevant to clutch release movement.
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