Do not downshift..... do not

nrpetersen said:

The pricing of that alignment tool just might have been one of BMW's big blunders.

It is only a couple of lathe diameters on a piece of screw stock that are reasonably concentric. I cobbled one for my 1100RT on my old Logan lathe but probably since made it into something else.

No way should techs be made to own one. This is a shop item.

BTW - What are the diameters and lengths? Can we get a mail based loaner program going?

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Check out www.rbracing-rsr.com/bmw_clutches.html seems they sell an alignment tool for about $20 as well as an interesting clutch guaranteed to end spline issues forever more.

The last clutch centering pin I bought from BMW was about $35, a few years ago.

The alignment jig for the K-bikes is probably substantially more, since it's not just a pin.

Are these the BMW tools we are talking about to align the clutch pack to the flywheel housing??

One of these fits 1100's, one 1150's...forget which is which at the moment
stamped in numbers:
left tool- 21 2 6707673
right- 21 3 680

Not a deal breaker price if you need one, forget the pricing, but was not enough to keep me from buying them.

Some specialty tools are pricey and not used daily, so why would an average tech buy them? Most shops have a huge tool board with every goofy tool made hanging in it's numbered spot.Some may be used once a year, some rarely as that model is not a popular model moving thru a shop anymore.
I am currently waiting on a K12 Wedge engine crank locking pin...the local dealers did not have it in their collection either. Have to have it to replace the cam chain drive sprocket.

and as Anton mentioned, the K bike jig looks expensive!

While reading the RSR site I noticed the different diameters and spline counts of the various models they list. Twenty bucks is not outrageous for a proper clutch pack alignment tool if you don't have a lathe to make your own.

Interesting to note the 1100 splines are 180MM and have 24 splines (except the S model)

- Then the 1150 is smaller at 165MM but has larger splines with a 17 spline count.

- Finally the 1200 goes back to the 180MM diameter but now with a 17 spline count.

That is 3 different combinations of shaft diameters and spline counts over the 3 models. Makes me wonder why would they do that?

156327 said:

While reading the RSR site I noticed the different diameters and spline counts of the various models they list. Twenty bucks is not outrageous for a proper clutch pack alignment tool if you don't have a lathe to make your own.

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I tried to buy one. I couldn't get them to answer an e-mail. Let me know if you have any luck.

156327 said:

While reading the RSR site I noticed the different diameters and spline counts of the various models they list. Twenty bucks is not outrageous for a proper clutch pack alignment tool if you don't have a lathe to make your own.

Interesting to note the 1100 splines are 180MM and have 24 splines (except the S model)

- Then the 1150 is smaller at 165MM but has larger splines with a 17 spline count.

- Finally the 1200 goes back to the 180MM diameter but now with a 17 spline count.

That is 3 different combinations of shaft diameters and spline counts over the 3 models. Makes me wonder why would they do that?

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Also interesting to note that spline issues are largely absent with the 1200 models.

Red100RT said:

Also interesting to note that spline issues are largely absent with the 1200 models.

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Yeah.. this is what has me wondering. Perhaps they hit upon the right combination of larger diameter shaft with fewer splines that are larger and thus more robust.

I have no idea how to calculate it but I suspect the difference in contact area is significant. Maybe this has something to do with the failures?

Hello BCBeemer, I was at the Boise beemer dealer couple days ago and I think I must be loosing it because there for sure isn't an O2 sensor south of the cat. I am for sure getting old. Resisted the temptation to buy the beauty though.

You know manual auto trans have input shafts larger in diameter and very thick splines, hmmmmmm....

bikerfish1100 said:

this is from the other current input shaft thread (currently just a spot or 2 below this one in the Oilheads forum):

"Also quite important is that most (if not all) automotive input shafts have a reduced diameter tip which seats in a pilot bearing in the crank or flywheel. The fact that we have a throwout bearing / push rod running through the middle of the input shaft prevents this on our bikes in order to minimize the bell housing length (front to rear)."

it is not exactly a case of apples and oranges being compared here.

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From having replaced the clutch on a couple of my cars when younger, I have to say that the input shaft on the transmission then was straight, not tapered. There was definitely a throw out bearing moved by a fork operated by the clutch pedal. Unless I am misreading the somewhat confusing excerpt you posted it sounds like apples to apples to me.

Note how the tip of this input shaft is a smaller daimeter than the spline and rides in a pilot bearing or bushing in the crank shaft (sometimes in the flywheel). This is basically how most (maybe all) automotive clutches are configured.


On our bikes, the transmission input shaft is hollow with a push rod running through it from the thrust / throwout bearing to the diaphragm spring. The throwout bearing is located at the back of the transmission instead of riding on the input shaft like it does on a car.



The difference is that the automotive input shaft is aligned with the crank / flywheel because it is inserted into a pilot bushing / bearing in the crank or flywheel and our bikes don't get that alignment feature.

That means the stack up on your car looks like this:
Input shaft, pilot bearing, flywheel (optional), crankshaft

On our bikes it looks like this:
Input shaft, bearing, transmission housing, dowel sleeves, engine housing, bearing, crank shaft, flywheel

Another difference is that in addition to a pilot bearing, cars almost universally have a torsional damper spring setup contained within the clutch disk, that allows a small amount of radial motion of the input shaft with respect to the crankshaft. The torque is carried by the spring system, which is slightly radially compliant.

On our bikes there is only a flex plate, which is radially very very stiff.

Q - Do all bike clutches have this flex plate? do any have the torsional damper setup?

I believe any bike with a single plate dry clutch (BMW airheads, oilheads, Guzzis, most Ducatis, older Harleys) do not have the radial shock load springs incorporated into the clutch fraction plate. It may be a cost issue, but more likely a weight and complexity issue. Could also be a clutch pack thickness issue, as most cycle dry clutches have limited space between the flywheel and pressure plate.

Delaware.Dave said:

I'll let you all know how it turns out.

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Okay, so one shaft lube operation and one hernia operation later (not related) and the bike has sat for over a week. The doctor hasn't given me the green light to ride yet, so the bike has waited. These are the things I learned from watching the technician.

• The job isn't so hard that a couple of guys couldn't tackle it. Be meticulous and organized and you should be okay.
• Use a service manual. We probably disassembled more than we needed to.
• Digital camera. Take more pictures than you think you need. It's not like you're buying film.
• That 12 year old bike did not want to come apart, and slowed our work down to twice as long as it should have taken.
• Bleeding the brakes was a stone bitch for us. The rear had to be bled through 3 or 4 times, and I still haven't test ridden yet.
• If you've disconnected the throttle or clutch, and in our case, spilled the rear differential fluid, then just go ahead and do the required annual service and then the bike will be fresh and ready to go.

I'm so glad that job doesn't happen often.