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2003 BMW K1200 LT (88K on 2020/08/13)
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Discussion Starter #1
All:
I'm preparing to change the clutch on my 2003 LTE @ 90K, and after reading/reviewing so many posts about the LT's biggest job, that seems to be the weakest point of our favorite ride, the clutch or other aspects of it's operation: The seal of the input shaft to the trans, the rear main seal from the motor or the clutch slave cylinder, all concerns for contamination. What I suspect could have been considered as a more permanent fix in addition to replacing the possibilities, would have been to beef up or have heavier spring for added pressure when engaged. Having purchased all new parts for this impending job, curious if any veterans or novices like myself have an opinion or advice as to whether a modified spring might be a viable possibility?

Without having done this before, my first thought would be to replace the wire/spacer ring entirely depending upon it's thickness with something thicker for added pressure, or to possibly merge to diaphragm springs into one (Modified of course). In Searching the net I found this, interesting read, and clearly points out that using two springs is not recommended, not my intention to use two complete springs, was thinking one complete with the other only half tines mid way up and would also have this balanced.
Joe
 

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Wrencher Extraordinaire
2005 K1200LT
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It is a big job but a well cared for clutch can last a very long time. Never exceed 1500 RPM when launching until the clutch is fully engaged will do a lot for longevity. As far as seals go that is always a factor but I have never replaced a seal that wasn't leaking (does that make sense?). The slave can be replaced at a good interval like 60K and is very easy. Once in there for the first clutch use a Viton 19 x 4 mm o-ring on the output shaft as that is the main item from the engine side that leaks. I suspect that a stronger spring could stress the tiny throw out bearing in the end of the slave cylinder so that would not be good either.
 
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It might sound like a good idea to increase the thickness of the wire ring but without additional engineering, you will not have an operational clutch when done. As you put the clutch parts together, the spring is compressed. You might think thickening the ring would not cause adverse reactions on the rest of the clutch BUT, this would be very similar to having a clutch disk that is too thick compressing the spring farther than normal which will pull the center farther down away from the slave cylinder and your clutch push rod will not be long enough to disengage the clutch. If you are relaly interested in having a stronger clutch, you can do a hack posted by RBRACING which never to my knowledge produced anything but vaperware for an LT. You could and I am not recommending this, use the R1150GS spring which is supposedly thicker 2.00mm and stronger. Part Number 21 21 2 345 597 The stronger spring would put more stress on the throw out bearing and create higher pressure in the clutch hydraulics on the LT so you might have a stronger clutch only to have a failure at a different point on the slave causing oil contamination from there and have to do it all over again sooner than later. It would be your choice. There is no upgrade for the slave parts and abuse with hard fast starts will just wear the clutch out faster. If you are interested, I can send you a Viton 4X19mm O-ring if you don't have that yet. I would recommend if worried about leaking and contamination, changing the trans input shaft seal with the dealer Viton ( orange) seal as it will hold up better against the heat generated by the clutch than a Buna one. As John has never replaced a non leaking seal, I am not him LOL. I would also consider replacing the rear main output shaft seal but be careful installing the clutch basket as you can damage it if too rough and it goes in dry. The last one and probably the most difficult seal is the slave seal also now in Viton from the dealer which will better resist brake fluid if the slave does leak although it will not prevent fluid contamination down the clutch push rod. It's placement is critical as there is an oil passage it needs to block and won't if installed a tad too deep.

Good luck and let us know how it goes.
 

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All:
I'm preparing to change the clutch on my 2003 LTE @ 90K, and after reading/reviewing so many posts about the LT's biggest job, that seems to be the weakest point of our favorite ride, the clutch or other aspects of it's operation: The seal of the input shaft to the trans, the rear main seal from the motor or the clutch slave cylinder, all concerns for contamination. What I suspect could have been considered as a more permanent fix in addition to replacing the possibilities, would have been to beef up or have heavier spring for added pressure when engaged. Having purchased all new parts for this impending job, curious if any veterans or novices like myself have an opinion or advice as to whether a modified spring might be a viable possibility?

Without having done this before, my first thought would be to replace the wire/spacer ring entirely depending upon it's thickness with something thicker for added pressure, or to possibly merge to diaphragm springs into one (Modified of course). In Searching the net I found this, interesting read, and clearly points out that using two springs is not recommended, not my intention to use two complete springs, was thinking one complete with the other only half tines mid way up and would also have this balanced.
Joe
I am curious as to why you feel a need for more clutch pressure? I have not heard of a healthy clutch slipping on an LT. The only slipping clutches I have read about or experienced myself are clutches that are either oil contaminated or that are worn out. To me the weak link in the LT clutch is not the clutch per se, but the crappy seals that were used originally allowing all sorts of leaks. I think an LT clutch that is kept dry with good oil seals and not abused will last the life of the bike. When I changed my clutch at 54,000 miles due to oil contamination, I measured the wear on the disk and when extrapolated to the disk wear limit, it would have lasted 700,000 miles. That is not a typo.
 

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2003 BMW K1200 LT (88K on 2020/08/13)
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Discussion Starter #5
All: (John, Gordon and Voyager)
Thank you for your input, opinions and advise. As I implied, I posted this inquiry because I'm a tinkerer, but mostly because I was hesitant in spending the time honing my already well established sailor language (#$#@^%&*%[email protected]), and finding new words along the way. You gave me exactly what I was hoping for, and welcome any additional words of wisdom.

If I understood all that you've collectively said, it is:
1. Use New Parts.
2. Seals should be made of Viton material lightly lubricated on wear surface, considered the expense of microlube gl 261 for the splines, kinda costly.
3. Take my time and don't brutally mis-handle the job.
4. After successfully assembling, starting off should be done gently No more the 1500RPM's! (Something I already practice due to slippage and no desire to be the first in a California intersection).

I like the idea of replacing the 1.75 mm original with R1150GS 2.00mm thicker plate over any other mods and had actually read that in the RBRacing thread. I by no means now or ever intend to race my smooth operator, I'm much more keen on the idea of riding, not watching my ride sit., because I destroyed something tinkering.

Parts purchased, hardware from BMW, most of the clutch components from Wunderlich in NC and some sourced parts from Amazon.

The Disk, Pressure Plate, Spring and Housing (flywheel) sourced from Wunderlich

PlatePressureSpringDisk.jpg


Hardware sourced from BMW, including the single O-ring which I believe is Buna.

Hardware1.jpg


Hardware2.jpg


Additional O-rings, sourced from Amazon viton 19x4 -75

Hardware3.jpg


RearMain seal, made of Viton with spring tension double lip design (the modification I think will work better than the original equipment)

VitonRearMain-1.jpg


VitonRearMain-2.jpg


VitonRearMain-3.jpg


Thank you again gent for the wise advise, this time through I stick by the book!
 
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Joe, it looks like you are just about ready. How does your stop disk look between the clutch basket and the output shaft? at 50K, mine was worn but I probably could have reused it. I replaced it and kept the old one somewhere just as a reference piece.

The 50X80X10 in Viton will probably not have any issue versus the OEM Teflon but there is about a 100 degree functional difference between the two. Not sure why they used Teflon there unless it was for heat and maybe durability but they also used Teflon on the front hall sensor flange and heat would not really be an issue there. I know it could get really hot in there with stop and go traffic. This will be the first time I have seen someone use a Viton for the rear main so good luck on that tinker. I don't see the trans input shaft seal in your pile. Are you going to leave that one alone?
 

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2003 BMW K1200 LT (88K on 2020/08/13)
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Discussion Starter #7
Gordon:

Thank you for your response. I went the Viton Rear Main, said to hold up to high temp's much better than Teflon (study), but also the wear-ability and mechanical aspects of the material. I wanted something that would remain more flexible with two points of seal (Inside and Outside), thinking that with 90K and not knowing how the bike was treated/riden before me, there may exist more crankshaft movement.

As far as Stop Disk, I have a new on of those as well, just didn't picture it. And for the Trans input, still need a source for that, couldn't find any dimensions etc, may have to go to BMW for that, unless you know of another source?

Again, Thank you!
 

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The seal is a 20X32X8 by the MAX BMW fiche. It is now Viton from the dealer and has a felt patch maybe to catch clutch dust or metal filings or something. really not known by me.

23 12 7 705 086​
SHAFT SEAL - 20X32X8​
0.02​
1​
$24.62​



171298
 

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2003 BMW K1200 LT (88K on 2020/08/13)
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Discussion Starter #9
Gordon:
Thank you, after my last post, I went to the MAX BMW site and found exactly that. I will get that ordered ASAP. I'm in no real hurry to start this, not with as hot as it's been here lately. Just miss riding and have never had a ride where the clutch didn't slip, so I'm excited about riding after I fix this.
 

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Now that we have accumulated the necessary parts, do you know the cause of the slipping? was there contamination or was it just worne out? I scanned through your other thread and didn't see mention yet or if you even have it apart yet?
 

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2003 BMW K1200 LT (88K on 2020/08/13)
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Discussion Starter #11
Gordon:

The last owner seems to have maintained general maintenance on his own and not had any real serious work done. The two owners before him , have everything documented, and it appears that it had two clutch replacements done almost back to back. I have not yet opened it up my smooth operator, I'm working with my cousin, who has a sheet metal fab shop, where I used to work, to possibly fab a custom made lift that I'll be able to use for years to come.

Once I've opened it up, I'll post some pics, my suspicion is that it is the clutch slave cylinder, I do have oil drops occasionally, there is almost no smell to the dirty oil, or I have the covid again.

Thank you
 

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OK, will look forward to the documentation of your journey into true LT ownership ;) Curious about the two clutch jobs back to back? Was that documented at a dealer or by the owner?
 

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2005 K1200LT
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Two tid bits. 1. just use a very very thin coat of molly lube on the splines. 2. Leave the F-R switch on the transmission, disconnect at the connector, too easy to break the tips of the micro switches when pulling it off the shaft.
Also make two long M8 bolts to slide the transmission off the engine.

171300
Reverse switch.jpg
 
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2003 BMW K1200 LT (88K on 2020/08/13)
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Discussion Starter #14
John:
Thank you for the Tid Bits, seems easy enough to follow!

Gordon:
Dealer documented clutch replacement seems I remember them taking place in 05 or 06. I bought the smooth operator in 05/2019 with 63K, has 90k on it now almost every weekend a couple of hundred miles met my tires.

Anybody:
Recommendations on alternative Molly Lube to replace MicroLube Gl 261?
 

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Wrencher Extraordinaire
2005 K1200LT
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I use Honda Molly 60. If you can't find any I'll send you a little packet of it.
 

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Another option would be the Casterol Optimol TA paste BMW part number 18 21 9 062 599 if it is still available. A little goes a very long way and the tube will do 100 clutch and drive shaft spline jobs.

18219062599
ASSEMBLING PASTE - 100G​
0.25​
$21.99​
 

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Discussion Starter #17
John,
I found some on Amazon, thank you for the offer.
 

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When you install the rear main seal, cover the splines with one layer of electrical tape spiraled out. Don't let the splines cut the inner lips of the seal as you press it on. Of course check depth which is important here.
If you want to borrow the installation tools needed and other stuff from the Clymers manual, let me know PM. I can mail them to you via USPS priority mail and then you can return them.
 
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beech, the rear main seal comes nowhere near any splines. You must be thinking of the gearbox input shaft seal.

171312
171313
 

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Discussion Starter #20
John, Gordon and Beech.

Thank you, because my previous wrenching has been on Fords and Chevy's and this is a BMW, I'll take my time so as not to increase my already extensive foul mouthiness and I know I want it done right the first time, so I'll take it easy peasy. Again thanks!

Beech.
I believe I have everything I need, except a few things I was going to have to fab,like the Flywheel/Clutch plate bar. If it isn't too much to ask, can you take pictures of some of the special tools, just so that I have a reference with which you're speaking of (send PM), because I may take you up on that offer. I did just purchase 30mm Deep Impact.

Gordon:
Also late thanks for the BMW Lube number/pic, I did find it on MAX,but had already ordered the Honda Moly on Amazon.
 
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