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The mc gods have decided to have fun with me. The clutch splines on the 85 K100RS are stripped at 110k. How difficult and expensive is it to replace these splines? The clutch is a total mystery to me. Do I need any special tools to do this? I have access to a used transmission if the splines on the the transmission shaft are worn.
 

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97tiger885 said:


The mc gods have decided to have fun with me. The clutch splines on the 85 K100RS are stripped at 110k. How difficult and expensive is it to replace these splines? The clutch is a total mystery to me. Do I need any special tools to do this? I have access to a used transmission if the splines on the the transmission shaft are worn.
I just replaced this and the input shaft this winter. Most will tell you that they both should be replaced at the same time because of wear pattern. You don't want to prematurely wear a new part because its mate is settled in its ways. I was able to replace just the clutch plate on my bike and not replace the entire clutch. I know it isn't the best way to do it but it was all I could afford. I made the special alignment tool at my shop on my lathe and it worked like a charm. Maybe you can find a shop nearby that could loan you one. you only need it for about 1 minute.
Be sure to mark everything with orientation marks when you pull it apart so you know the exact way to put back together, I usually use just a paint pen. Or the ol' lady's nail polish.
like I said, just replacing clutch plate isn't ideal but worked for me. I measured and checked the pressure plate for dishing and that helped me decide if it was worth a shot.

By the way my surging problems have gone away. either fixing worn rubber or cleaning MAS fixed it. not sure which. Good luck
 

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flyrigger said:
I just replaced this and the input shaft this winter. Most will tell you that they both should be replaced at the same time because of wear pattern.

By the way my surging problems have gone away. either fixing worn rubber or cleaning MAS fixed it. not sure which. Good luck
By "this," you mean the friction plate?

You have a K75? According to Clymer, the K100s do not need an alignment tool to keep the housing from spinning. You can put a hammer handle into one of the holes in the housing.

This might not be such a horrible repair after all.
 

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97tiger885 said:
By "this," you mean the friction plate?

You have a K75? According to Clymer, the K100s do not need an alignment tool to keep the housing from spinning. You can put a hammer handle into one of the holes in the housing.

This might not be such a horrible repair after all.
Aaahhh, the centering tool. I hadnt gotten to reassembly.
 

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97tiger885 said:
Aaahhh, the centering tool. I hadnt gotten to reassembly.
Yes, the "this" is the friction plate. The part with the splines on it. And yes on a K75 but I imagine it would be the same process

You don't need anything special to disassemble but the alignment tool ( or a homemade one) is crucial for reassembly.

I was able to get the input shaft locally and rebuild it with existing parts and some homemade bearing and gear pullers. I have a bit of a thread on here with some photos when I was going through this problem I believe.
Good luck. It seems daunting but it isn't too bad. Just save the beers for when you are done working on it for the night or one can forget crucial steps. Or so I heard.
 

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flyrigger said:
Yes, the "this" is the friction plate. The part with the splines on it. And yes on a K75 but I imagine it would be the same process

You don't need anything special to disassemble but the alignment tool ( or a homemade one) is crucial for reassembly.

I was able to get the input shaft locally and rebuild it with existing parts and some homemade bearing and gear pullers. I have a bit of a thread on here with some photos when I was going through this problem I believe.
Good luck. It seems daunting but it isn't too bad. Just save the beers for when you are done working on it for the night or one can forget crucial steps. Or so I heard.
I ordered a centering tool off ebay. I have been told you can do it without the tool if you have a lot of patience and a little luck. Tool was only $25. Worth it to save myself the frustration.

Glad to hear the surging is gone.
 

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Discussion Starter #7
On the road again

97tiger885 said:


The mc gods have decided to have fun with me. The clutch splines on the 85 K100RS are stripped at 110k. How difficult and expensive is it to replace these splines? The clutch is a total mystery to me. Do I need any special tools to do this? I have access to a used transmission if the splines on the the transmission shaft are worn.

After way too much time, money, blood, sweat and cursing, the 85 K100RS lives again. Had to remove the tranny three times to get it right. Turns out the clutch plate while very worn was working. The failed part was the diaphragm. MC is fine after 10 test miles. Mechanic at Finger Lakes did this in 43 minutes with a helper. (Friends watched and timed.) Took me closer to 43 hours. Know way more now than I did 2 weeks ago.
 

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Ha ha, that's amazing. when I owned my 1985 K100RT in 1991, the starter clutch started slipping due to oily blowby of the rear main seal, so, with no internet help and working off my Clymer(?) manual, I spent a day seperating the frame from the engine/drive-train assembly.

Up until now, I had no idea that you can remove the transmission from the bike without seperating the two! Cheers, Terry. :wtf:
 

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The clutch centering tool is not crucial for reassembly. I've put together numerous clutches without one.

Leave the six clutch bolts somewhat loose so that there's enough friction to hold the clutch plate in place but it can still move. Feel around the edges of it and get it roughly centered. Without the pushrod, wiggle the transmission on until it mates with the clutch plate and silde the transmission all of the way on. (You're effectively using the transmission as your centering tool.) Pull the transmission STRAIGHT back and off.

Tighten the six clutch bolts.

Slide the transmission on once more just to be sure.

Lube the transmission input splines, insert the pushrod and install the transmission. Easy peasy.
 

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Discussion Starter #10
FlyingDuck said:
The clutch centering tool is not crucial for reassembly. I've put together numerous clutches without one.

Leave the six clutch bolts somewhat loose so that there's enough friction to hold the clutch plate in place but it can still move. Feel around the edges of it and get it roughly centered. Without the pushrod, wiggle the transmission on until it mates with the clutch plate and silde the transmission all of the way on. (You're effectively using the transmission as your centering tool.) Pull the transmission STRAIGHT back and off.

Tighten the six clutch bolts.

Slide the transmission on once more just to be sure.

Lube the transmission input splines, insert the pushrod and install the transmission. Easy peasy.
Good to know. I am happy with the centering tool. It saves me from pulling the tranny off one extra time. But now I know how to do it.
 

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I got caught also years ago replacing the friction disk only. Had to go back and replace the spring. Followed a few others that had the same problem, doesn't take too much heat from a slipping clutch to remove the tension on the springs. BMW used to give spring height specs on the older bikes,not anymore and not so easy to do since they "built" the big washer thingie into the diaphragm spring.

A medical scale,a used spring and the shop press gave me lately a little bit of a data point/specs. Maybe next time when I have a new spring in my hands, hopefully not for another 50,000 miles.

Takes over 200 lbs to compress one of them springs. :teeth
 
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