Input Spline replacement?

[Andre1150]

How much wear is too much wear on the transmission input spline? The teeth are all still there, but there are a few splines that look warped. Although most of the damage looks like its on the clutch plate mating area, not the spline itself.

 

 

If I'm in there doing the clutch, shouldn't I just replace or refurbish the spline too while I'm at it?

 

Recommendations/thoughts ? (this is the first time I've ever been this far into the bike)

 

[mneblett]

When my input shaft had that much wear, I had it replaced. It is not a trivial job, as that is the end of the transmission input shaft.

 

You could reinstall the tranny as is with a new clutch plate, but that will likely result in accelerated wear.

[Boomer343]

I replaced my input shaft and it was less worn than yours. It really depends on your skill set whether you should attempt this. Besides needing to use heat to take it apart and again to reassemble you will also need some measuring tools and bearing splitters/pullers. Most home mechanics will pass on doing this repair.

 

Depending on how many miles you are expecting to put on the bike you have two options as I see it.

 

First is to locate a good used transmission and simply replace yours. Being where you live there should be some available close by.

 

Second option would be to get a new clutch disc and the spacer mod made by Cele. I would also suggest getting the rest of the clutch assembly as well. The spacer mod will maximize the spline contact area.

 

I did the rebuild plus the extension mod but would probably do option 2 if I was doing it again.

 

BTW how many miles on the splines?

 

 

[nrp]

There are a lot of different opinions on the value of greater spline engagement. You have as-manufactured radial misalignment & that is what has caused the spline surfaces to wear. You will probably also find the rear crankshaft main bearing is worn.

 

Personally I think that input shaft could be used again. But if it was my bike, I'd disassemble the transmission guts so an engine alignment measurement could be made to the transmission input bearing housing bore. There is a more detailed discussion of all this in a series of postings by SpaffyPD & myself at the pelican parts website. The dial indicator test rig is presently in Vancouver.

 

Also check here for the initial experiments with this:

 

http://bmwsporttouring.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=703209&page=3

[Jim Moore]

Ugh. I'm sorry to hear that. How many miles on the bike?

 

All of your options are expensive and painful. If you simply replace the input shaft you will almost assuredly have the same problem next time you hit this number of miles.

 

You have a few options. First, replace the shaft and install a spacer on a new clutch disk. You would be somewhat of a beta tester, but it might work for a long time.

 

You could send it to Tom Cutter at the Rubber Chicken Racing Garage. He claims to be able to repair the transmission so it won't happen again.

 

You could machine some offset dowels in an effort to align the transmission. That technique has seen some success.

 

The simplest idea is to buy a known-good used transmission. I'd look for one with at least 30,000 miles on it and no spline damage.

 

Good luck with whatever you decide.

[cele0001]

Could you post the picture of a clutch hub, showing wear?

[dirtrider]

Morning FireKit

 

How many miles to get to that wear point?

 

Those splines have a definite & decided wear on them. When you install a new clutch disk there will only be mating spline match up in a few places along the spline length until it wears in to match (& makes plenty of metallic particles in the process)

 

Very difficult call on JUST replacing the disk or spending the big bucks & added labor to install a new input shaft & check the trans front housing to crank-center alignment.

 

Personally my take is: it boils down to how much you want to spend on an older bike, how many miles you plan of riding it yet, & how far from home you plan on venturing.

 

If you don't ride it a lot then just a new disk will give you a lot of enjoyment for not a lot of money

 

New input shaft (& whatever else you find wrong inside the trans) & new clutch parts will put the cost to keep that bike in the (I better REALLY like that bike & plan to nurse it along forever category)

 

Tough call for sure --

 

Go ride a 1200RT then make your decision.

 

 

[Andre1150]

The old clutch -

 

 

The bike has 87,750 and is on it's second clutch. It was an RTP model that I bought with 56,000 miles two years ago. I'm not sure if the transmission was done or not, the local PD kept their own service records that I've not been able to get to.

 

 

[nrp]

Does the white stuff wipe off? Might it be white lead, which is an excellent anti-seize material but hazardous to ones health. I understand it is only EPA permitted for use by the military.

[Andre1150]

The white stuff feels like grease. I'll clean that off. .

[mneblett]

Does the white stuff wipe off? Might it be white lead, which is an excellent anti-seize material but hazardous to ones health. I understand it is only EPA permitted for use by the military.

White is the color of the BMW-recommended lube, Staberags (sp?). Normal to find on the splines, and no Pb hazard.

[nrp]

Probably someone lubed the splines in the past - someone with connections to get white lead? or the official BMW stuff?

[Andre1150]

Second option would be to get a new clutch disc and the spacer mod made by Cele.

 

Can anyone point me in the direction of this mod? And will it fit Siebenrock clutch plates or just the Sachs?

 

 

[Jim Moore]

Several good-looking transmissions on eBay right now. Nothing on Beemerboneyard though.

[Jim Moore]

Second option would be to get a new clutch disc and the spacer mod made by Cele.

 

Can anyone point me in the direction of this mod? And will it fit Siebenrock clutch plates or just the Sachs?

 

 

Here's a link to another site with Cele's info. He's also on advrider. I think he's on here too.

 

http://forums.pelicanparts.com/bmw-r1100s-r1200s-tech-forum/871825-r1100s-post-spacer-install-disc-slop-video-after-16k-miles.html

[AndyS]

Is there any date code on that gearbox?

It is unusual for a 2004 bike to display that sort of wear. Especially as it has, to your knowledge, had 2 clutch discs. The one you have now is amazing. It wouldn't be long before those internal splines just disappeared and left you stranded in the middle of nowhere!

[mneblett]

Is there any date code on that gearbox?

It is unusual for a 2004 bike to display that sort of wear.

Perhaps not. My '04's splines looked exactly like that.

[dirtrider]

Is there any date code on that gearbox?

It is unusual for a 2004 bike to display that sort of wear. Especially as it has, to your knowledge, had 2 clutch discs. The one you have now is amazing. It wouldn't be long before those internal splines just disappeared and left you stranded in the middle of nowhere!

 

Morning Andy

 

It's an RT-P (police bike) -- no telling what kind of life it led in previous duty.

 

If it did city duty then probably thousands of vehicle launches weekly with lots of clutch use on shifting per day. If it's on it's 3rd clutch in 87K then someone was using it for more than light touring.

 

I have a couple of LEO (Law Enforcement Officer) friends & both ride police bikes, they are HARD?HARD?HARD on their motor units.

[roger 04 rt]

Second option would be to get a new clutch disc and the spacer mod made by Cele.

 

Can anyone point me in the direction of this mod? And will it fit Siebenrock clutch plates or just the Sachs?

 

 

Here's a link to another site with Cele's info. He's also on advrider. I think he's on here too.

 

http://forums.pelicanparts.com/bmw-r1100s-r1200s-tech-forum/871825-r1100s-post-spacer-install-disc-slop-video-after-16k-miles.html

 

Although this is a sample of one, a friend who also used another solution to produce a full engagement (after two prior clutch replacements at 30/40,000 each) has a similar number of miles, with no wear, like the clutch in the video. Neither had any realignment of transmission to engine.

 

I think it's time to consider that the problem of clutch hub and input-shaft wear has more moving parts (pun intended) than merely misalignment. After all, EVERY transmission and engine is misaligned by some amount, it's only a question of how much.

 

 

[roger 04 rt]

How much wear is too much wear on the transmission input spline? The teeth are all still there, but there are a few splines that look warped. Although most of the damage looks like its on the clutch plate mating area, not the spline itself.

 

 

If I'm in there doing the clutch, shouldn't I just replace or refurbish the spline too while I'm at it?

 

Recommendations/thoughts ? (this is the first time I've ever been this far into the bike)

 

The old clutch -

 

 

The bike has 87,750 and is on it's second clutch. It was an RTP model that I bought with 56,000 miles two years ago. I'm not sure if the transmission was done or not, the local PD kept their own service records that I've not been able to get to.

 

 

There is CLEARLY a different pattern of wear on the input shaft (scalloped) and clutch hub (linear). And it is the pattern commonly seen in these failures. It would be great if someone had a theory that explained this.

[roger 04 rt]

This is probably more than anyone wants to read, but here's a model of how the scalloped wear might happen from a post last year.

 

Input Shaft Photo from Anton Largiader

 

 

These pictures show the common pattern seen on the R1150 transmission input shafts when there has been excessive wear. Many possible causes and solutions have been identified and debated and there have been a couple good threads recently: Checking for spline wear 1999 R1100S, and tranny input shaft. Looking at the pattern of wear on the spline, which occurs inboard on the shaft and at an angle to the spline tooth, it can be hard to imagine how or why that exact shape develops. For months I've been thinking about a model for the wear pattern on the R1150 input shaft and feel that I've come up with one.

 

Many assert that misalignment is the ultimate root cause of wear. It is my view that misalignment (of some type) gets the wear started and other problems cause it to accelerate. The key to the pattern of wear on the input shaft is that all misalignments, whether flatness of the clutch housing/flywheel or a shift of centerline between engine and transmission, result in an angular force on the clutch-hub which gets applied to the input shaft. (Since the transmission input shaft is in a separate assembly from the engine crankshaft, there will always be some misalignment, and it isn't known how much misalignment the R1150 can handle without excessive wear.)

 

The easiest way to imagine how misalignment leads to the angular force causing the wear that's observed is as follows:

 

Start with a perfectly aligned crankshaft/input shaft and then lower the transmission input shaft enough for an effective tilt of ~1 degree from the engine end of the clutch hub to the transmission end of the hub. Now imagine some play in the hub/spline coupling such that the tilt can actually happen. (This model also works if the clutch-housing/flywheel are tilted but wear progresses around the shaft/hub as clutch release/reengagement changes the hub-flywheel rotary position. Also, I am only using a downward shift as that is easier to explain. Any shift yields the same results.)

 

With the transmission lowered and viewed from the rear:

 

--the clutch-hub splines in the 12 o'clock position are up at the engine end.

 

--the hub splines at the 6 o'clock position are down at the transmission end.

 

--the clutch-hub splines at 9 o'clock position press on the input shaft only at the end near the transmission and are up off the input shaft at the engine end.

 

--and the hub splines at the 3 o'clock position contact the input shaft only at the engine end and are down and off the input shaft at the transmission end.

 

These differing contact points lead to wear since there is extra pressure and the surfaces change continuously as the shaft turns.

 

The "give" in this system, is the sheet metal web that holds the clutch-hub to the disc. As the engine rotates, the contact points change position such that in the y-axis (12-6 o'clock) the splines are rocking up and down, end to end as the shaft turns. And in the x-axis the clutch-hub contact point moves from the engine end of the transmission spline, to the transmission end as it rotates. (And also, based on an amount equal to [1-cosine{misalignment angle}] there would be a tiny in/out motion along the transmission shaft.)

 

This pattern of contact would vary continuously as the clutch-hub rotates (in a sort of figure 8 pattern) with the teeth sliding on one another at high pressure. Further, under hard acceleration, it is possible the forces are great enough that the 9/3 o'clock positions might flatten against the shaft, meaning more motion under even higher pressure. Whether that happens or not, the contact area on the splines, and hence the pressure would get very high as they pass through the 9/3 o'clock positions. That high pressure in the model is what I'm postulating leads to the wear.

 

There's another factor that may speed wear once it has begun. The engine produces its torque for only about 1/3 of its rotation. That means that the torque during the 1/3 period is on average 3X the torque reaching the rear wheel. Peak torque within the 1/3 period would be even higher. The damping of these peaks doesn't happen before the hub-spline engagement, it happens in the transmission. Whether this plays a role in acceleration of the wear is a question.

 

What might improve things? Better flywheel/clutch housing flatness, better crankshaft to input shaft alignment, harder materials, lasting lubrication, longer hub/spline engagement to effectively tighten the coupling and limit the range of motion. It seems each situation will be different.

 

I plan to measure flywheel flatness, lubricate and possibly extend the clutch hub, all depending on what I see when I open it up, I'm at 30,000 miles.

RB

 

Damper photo from GSAddict

 

 

[cele0001]

It will only fit the BMW clutch. It will not fit the Siebenrock clutch.

Main thread discussing the mod is on the ADV rider, but they are in process of changing forum software. Feel free to contact me directly if you need additional info.

esmir(dot)celebicAtgmaild0tcom.

 

There are currently 100 pieces out there, with 15 or so confirmed installs. In due time we should have the long term data. The longest test so far is from pelican forums thread.

Original hub failed at 19k miles, and there are currently 18k miles (and counting) on the modified hub and new shaft. Transmission housing is still original.

 

 

Here is another one with almost the same scenario as yours. Most of the discussion is there so no need to repeat it.

 

http://forums.pelicanparts.com/bmw-r1100s-r1200s-tech-forum/867739-r1100s-input-shaft-spline-repair-chronicle.html

 

[dirtrider]

How much wear is too much wear on the transmission input spline? The teeth are all still there, but there are a few splines that look warped. Although most of the damage looks like its on the clutch plate mating area, not the spline itself.

 

 

 

If I'm in there doing the clutch, shouldn't I just replace or refurbish the spline too while I'm at it?

 

Recommendations/thoughts ? (this is the first time I've ever been this far into the bike)

 

The old clutch -

 

 

 

The bike has 87,750 and is on it's second clutch. It was an RTP model that I bought with 56,000 miles two years ago. I'm not sure if the transmission was done or not, the local PD kept their own service records that I've not been able to get to.

 

 

There is CLEARLY a different pattern of wear on the input shaft

(scalloped) and clutch hub (linear). And it is the pattern commonly seen in these

failures. It would be great if someone had a theory that explained this.

 

Morning Roger

 

Theory only here--- This is the 2nd clutch disk (picture) so my SWAG is some of

that scalloped wear came from the 1st clutch disk, then 2nd disk

mismatch-up to the (already worn) partially worn splines.

 

 

[nrp]

We should also be looking at what could cause the extreme amount of unidirectional rear main bearing wear in the engine as documented by SpaffyPD at the Pelican Parts website. Crankshaft main bearing wear certainly isn't caused by spline engagement. It has to be caused by radial misalignment and loading.

 

I contend the scalloped wear pattern on the input shaft spline teeth is due to off-axis rotation (evolving from resulting wear) of the clutch hub, which is forced by the offset between the rotating centers reacting with the spider/flex plate inside the clutch disk.

Thoughts -

 

1) A replacement transmission should be checked for radial alignment even if its input shaft seems OK.

 

2) Per SpaffyPD, dis-assembly of a transmission to allow an alignment check is not a major job providing the input shaft isn't changed.

 

3) The effect on spline life of a retaining a sloppy rear main crankshaft bearing is still unknown.

 

4) We still don't know if the alignment problem is from manufacturing errors in the engine - or the transmission. BMW seems to have bought their way out by assuming it is with the transmission though.

 

 

[dirtrider]

Afternoon_ All

 

BMW did furnish a service bulletin on the K bike clutch spline wear issue.

 

In part is says- Even a slight misalignment above .25mm (.0098") can lead to spline wear between the clutch disk & input shaft. (not sure I would call .010" misalignment s-l-i-g-h-t but BMW seems to)

 

Also no mention of angular misalignment .

 

So obviously BMW did do some testing on the old K bike spline wear problems.

 

[Andre1150]

It seems as if there's no spacer mod for the siebenrock clutch and for cost reasons [and to learn] I'm planning on pulling the tranny and doing the spline replacement myself. I'd still like to make a spacer by contacting a machine shop to make one for the siebenrock disc, as the siebenrock seems to have thicker metal and friction material Than the Sachs.

 

I'd welcome any advice, I did see a member on an r bikes forum (cdnguy, I think) who made a spacer for the siebenrock disc, but it was a one off.

 

 

 

[Jim Moore]

Out of curiosity, why are you going with the aftermarket clutch?

[AndyS]

Out of curiosity, why are you going with the aftermarket clutch?

 

+1

The OEM clutch material is fine and long lasting. It offers good feel and if you are looking at a different hub arrangement, cele0001 already has one available.

[Andre1150]

why are you going with the aftermarket clutch?

 

On the advrider site, i'd been reading about fouled clutches ending a ride Prematurely. As I have put ~16k miles a year on my bike, I've tended to travel long distances in remote areas, and I try to have a basic plan for failure. Ie. I've removed the quick disconnects, moved the filter outside the tank, carry spare plugs, stick coils, HES, etc..

[Andre1150]

Roger,

I wonder if the issue starts even farther down the driveline, with the crank and crank bearings going out of round, creating a small wobble in the crankshaft and as each piston fires the resulting wobble forces the clutch plate around with a small amount of wobble, enough to start wearing the input spline. I showed my bike to an engine rebuild and he suggested that the error begins much earlier than the clutch or housing...just a theory. Maybe couple all the issues together causes the most extreme failure. .

[Boomer343]

Jeez if we ever solve this spline problem all we'll have are oil threads..... fire up at least one propane torch and take that trans apart, order parts and all the seals, replace the parts, put the parts in the freezer overnight, fire up the BBQ and roast the case then caulk it with the proper sealant and roast the other half real good to put it back together.

 

Ride the the bike to the end of any trail you want and have a big S grin on your face while you are doing it.... all the rest will just drive you crazy...or worse.

[roger 04 rt]

Roger,

I wonder if the issue starts even farther down the driveline, with the crank and crank bearings going out of round, creating a small wobble in the crankshaft and as each piston fires the resulting wobble forces the clutch plate around with a small amount of wobble, enough to start wearing the input spline. I showed my bike to an engine rebuild and he suggested that the error begins much earlier than the clutch or housing...just a theory. Maybe couple all the issues together causes the most extreme failure. .

 

I think that possibility should be explored as well.

 

However as I mention I know of two now who increased engagement, one I know personally, who got great long term results.

[Stan Walker]

Just remember that they all don't fail. Any explanation has to explain why only a few fail. Tolerance stack up I can buy. An out of round journal on a new crankshaft not so much.

 

 

[AndyS]

Hi Stan I agree that they don't all fail and there must be factors that effect this to.

This is NOT a criticism, just an observation...take your bike as a classic example. We know that your tyres last a VERY long time, you also get very good fuel consumption, so we can make an assumption that your ride VERY gently, this may well have an effect of the longevity of the clutch/shaft.

I do however think that your riding style is the exception, not the rule. As such, those who ride in other ways, may experience failure of their input shaft if there is any sort of issue with it.

[Stan Walker]

Guilty as charged. I don't ride like I stole it. I ride like I paid for it!

 

Still, there are those that claim use of low rpm torque aggravates the clutch spline wear and I am guilty of that as well.

 

I also don't preload the shifter, and do a full clutch pull to the handlebars when shifting.

 

As long as I'm confessing my sins perhaps I should own up to running 85W140 oil in both the tranny and final drive, another violation of what most feel is recommended by BMW.

 

I'm just a bad bad boy.

[roger 04 rt]

Guilty as charged. I don't ride like I stole it. I ride like I paid for it!

 

Still, there are those that claim use of low rpm torque aggravates the clutch spline wear and I am guilty of that as well.

 

The idea that low RPM riding accelerates wear doesn't stand the test of math. Low speed riding requires so little HP and Torque it can't be a factor in wear. At 40-50 mph, the HP produced at any RPM is in the range of 4-7 HP, minuscule.

 

If you look at the Torque required to create that HP, at 2500 RPM it's 8-15 ft-lbs. If you then open the throttle (not fully) and accelerate to 4000 RPM you produce about 20-40 HP and 30-40 lb-ft of torque

 

Compare that with a rider who is regularly riding at 4500 RPM (in any gear) and accelerates with WOT to redline. That acceleration period produces 60-90 HP and 50-70 ft-lbs. of torque.

 

So is it cruising where the input shaft torque is 5-10 ft-lbs. or is it the acceleration where the input shaft torque is 30/40 for the low-rpm rider and 50-70 lb-ft for the aggressive high-rpm rider? The answer's clear to me.

[roger 04 rt]

Just remember that they all don't fail. Any explanation has to explain why only a few fail. Tolerance stack up I can buy. An out of round journal on a new crankshaft not so much.

 

 

Good point, correlation isn't causation. Just because the journal is out of round doesn't mean that it is either cause or effect. You have to take lots of data to know.

[dirtrider]

Morning_All

 

No doubt in my mind that a larger than nominal rear main bearing clearance can add to spline wear but in my experience that isn't the main contributor.

 

A friend of mine just tore his high mile 2003 1150Rt apart for a rear main seal leak (bike has 128,xxx miles on it (he is the original owner) (first new clutch at 128,xxx also so he isn't a clutch abuser)

 

I rode over to help him install the actual seal & measure rear main radial wear (he did all the other work).

 

I took my indicator setup with me so we could measure the rear main bearing clearance (best we could with crankshaft still in engine)--That measured at .006" tight direction & .0085" loose direction. (that shows a fairly loose rear bearing/crankshaft wear especially in the firing directions)

 

While his input splines didn't look new they had very minimal wear & very little angular wear showing (perfectly fine to reuse).

 

I didn't measure trans to crank alignment as he didn't want to take the trans apart.

 

I haven't ridden with this guy in a while (we used to ride together a lot)-- he is definitely not a drive train abuser but he isn't a revver either. He also uses 6th gear a lot even at lower speeds-- I don't think he pulls it down to shuddering RPM's though.

 

Now I'm not sure WHEN the rear main wear occurred but probably not all at once so it has been wearing steadily over the bike's life.

 

At that rear bearing wear I'm pretty sure it would have been heard knocking at certain engine loadings (I'm going to ride the bike after he reassembles it to evaluate).

 

[Andre1150]

Following Esmirs spacer idea, I'm making a few spacers here that fit the Siebenrock clutch. I have both the Sachs and the Siebenock clutch discs and the Siebenrock fits tighter on the new $300 input spline I purchased. The Sachs has a little play, whereas the Siebenrock does not.

[roger 04 rt]

...

 

I haven't ridden with this guy in a while (we used to ride together a lot)-- he is definitely not a drive train abuser but he isn't a revver either. He also uses 6th gear a lot even at lower speeds-- I don't think he pulls it down to shuddering RPM's though.

 

Now I'm not sure WHEN the rear main wear occurred but probably not all at once so it has been wearing steadily over the bike's life.

 

At that rear bearing wear I'm pretty sure it would have been heard knocking at certain engine loadings (I'm going to ride the bike after he reassembles it to evaluate).

 

Afternoon DR,

I don't know what you've found but on my bike the shuddering RPM seems to be sub-1500 RPM in 6th gear, and then you have to add throttle to get it.

 

Be interested in your feedback after reassembly.

[roger 04 rt]

Afternoon_ All

 

BMW did furnish a service bulletin on the K bike clutch spline wear issue.

 

In part is says- Even a slight misalignment above .25mm (.0098") can lead to spline wear between the clutch disk & input shaft. (not sure I would call .010" misalignment s-l-i-g-h-t but BMW seems to)

 

Also no mention of angular misalignment .

 

So obviously BMW did do some testing on the old K bike spline wear problems.

 

Afternoon DR,

If BMW was concerned about > 0.010" of centerline misalignment, that looks like about 2 1/2 the times on the reference cited below in the thread.

 

There is 0.007" crankshaft play below, how do we apply crank shaft play to the centerline error, in other words how does one decide where the centerline sits when running, in order to measure centerline error?

 

Hi Neil, As an interested novice at this, I'm really delighted to see your efforts to help others measure the runout on their bikes. Although I accept that non-aligned centers of rotation is an issue, I would find it more satisfying if the theory of failure explained the different wear patterns on the two mating parts. The clutch hubs wear in a straight line but the transmission input shafts wear on an angle. This pattern is seen in every photo I've looked at.

 

Looking at the data below from the link I've provided, I interpret the data, as presented, to show 0.000 runout at some points, increasing to 0.0115" at the peak value. This means the centers are misaligned by half that figure, which is 0.00675".

 

For the crankshaft play, I will present them in pairs

7/8 vs 1/2 : 0.001 vs 0.006 center is 0.25 toward 1/2 o'clock

12 vs 6 : 0.0065 vs NA delta is (assuming 0.00175 for 6 o'clock) 0.002375 toward 12 o'clock

9 vs 3 : 0.0015 vs 0.003 center is 0.00075 towards 3 0'clock

4/5 vs 10/11 : 0.0025 vs 0.004 center is 0.00075 towards 11 o'clock

 

So the raw centerline deviation is 0.00675", but the crank while measuring the runout was (using 7/8 vs 1/2 o'clock) is 0.0025 off its center toward 1/2 during the runout measurement. That error is opposite the direction of runout. So I suggest the actual centerline deviation is 0.00675-0.0025=0.00425". Is a 4.25 thousandths of an inch error causing the wear we're seeing?

 

I completely agree that runout errors can lead to significant wear. But how is insertion factoring into this, and what is the dynamic motion of the pieces?

 

Quote:

These were the reading I got from measuring the transmission input bearing race:

TIR reading: 0.0115" with the maximum reading at the approximately 7-8 O'Clock position. So the transmission is high and right.

 

As a reference I measured the play in the rear main bearing and these are those numbers:

 

12 O'clock- .0065"

1-2 O'clock- .0060"

3 O'Clock- .0030"

4-5 O'clock- .0025"

6 O'clock- wasn't able to get good leverage- no reading

7-8 O'clock- .0010"

9 O'Clock- .0015"

10-11 O'clock- .0040"

[dirtrider]

Afternoon Roger

 

I really don't know how to correlate rear main bearing wear to spline wear.

 

A decided trans-shaft to crankshaft-center misalignment with a somewhat tight rear main bearing is fairly easy to understand the wear characteristics. (that joint always runs with a forced off-set, both straight offset & angular offset)

 

With a loose rear main bearing thrown in I really can't say without computer analysis assistance or running some long term dyno tests.

 

It' possible that a loose rear main bearing actually helps as that could (just a guess here) allow the crank to more center on an off-set trans alignment & take some of the un-lubricated gear mesh type spline wearing out of the system)

 

With a loose rear main, unless you hear it hammering (low RPM heavy loading), then it probably isn't jumping around through it's full travel potential.

 

I have seen a number of 1100's with high miles & rather loose rear main bearings that show little or no clutch spine wear. (you would think that if a loose rear main alone caused spline wear then we would be seeing a number off 1100's with failed splines also).

 

I have also seen a few 1150's with trashed splines at under 40K & normal rear main running clearance. (I just haven't worked with enough 1150 spline failure bikes to make any firm statements on main bearing wear vs additional spline wear.

On all the 1150 spline failures I have personally dealt with (or assisted with) none have had excessive rear main running clearance.

 

I think NRP has worked with a trashed spline bike & large rear main running clearance.

 

[Shane J.]

Found this thread because I have a problem which may be related. Please see my new topic "What the heck is that noise?"

 

Shane

[nrp]

I think NRP has worked with a trashed spline bike & large rear main running clearance.

I've only seen unidirectional main bearing wear (in an R1100 and in an R1150)- and in a direction that would be expected for a measured radial offset.

 

I suppose it would be possible that spline system wear is caused by an as-manufactured loose main bearing. In that case the transmission input bearing would take the crank rear loads across the spline. The manufacture of engine main bearing systems is highly developed - certainly by BMW. On the other hand, alignment of the engine-to-transmission axes has too many possibilities for screwups and it is not straight forward to measure in a production setup.

 

I'm still very suspicious that this alignment problem may well be from a flimsy clutch bell housing raw casting that becomes distorted when clamped/bolted in a fixture for the manufacturing machine center.

[roger 04 rt]

Four things:

 

1) All engines and transmissions are misaligned, it's only a question of how much.

 

2) We have to consider that other than centerline misalignment is causing the wear of the input shaft and clutch hub. The pelican parts link below shows an extended test of full shaft/hub insertion dramatically reducing wear. And I personally know of another bike, which wore out two hubs/shafts in under 50K miles each on an 1150, then went full engagement and has now ridden an additional 50K miles with no wear. In neither case was the transmission realigned to the engine.

 

3) The model of centerline offset errors doesn't offer an explanation of the scalloped wear on the input shaft versus the linear wear on the clutch hub.

 

4) In order to wear down the hub and shaft, the parts have to move with respect to one another in order for the wearing-work to be achieved. With a tight (but can still slide for clutch disengagement) fit between hub and shaft little work can be done. It seems to me that a short engagement offers greater possibility of a sloppy fit with motion, and a longer engagement reduces the ability of hub and shaft movement.

 

Second option would be to get a new clutch disc and the spacer mod made by Cele.

 

Can anyone point me in the direction of this mod? And will it fit Siebenrock clutch plates or just the Sachs?

 

 

Here's a link to another site with Cele's info. He's also on advrider. I think he's on here too.

 

http://forums.pelicanparts.com/bmw-r1100s-r1200s-tech-forum/871825-r1100s-post-spacer-install-disc-slop-video-after-16k-miles.html

 

Although this is a sample of one, a friend who also used another solution to produce a full engagement (after two prior clutch replacements at 30/40,000 each) has a similar number of miles, with no wear, like the clutch in the video. Neither had any realignment of transmission to engine.

 

I think it's time to consider that the problem of clutch hub and input-shaft wear has more moving parts (pun intended) than merely misalignment. After all, EVERY transmission and engine is misaligned by some amount, it's only a question of how much.

 

[nrp]

All engines and transmissions are misaligned, it's only a question of how much.

Your premise does not follow. At some point of minimal misalignment the spline teeth do not fret against each other, and the spline life becomes indefinite. There may be examples of extended life for a spacer-extended-engagement spline but there are a lot of non-spacered splines that also appear to have indefinite life.

 

On R1150s, every spline application that shows substantial measured error (generally greater than the DIN spec of >.003 TIR), And every one that shows wear, shows serious misalignment. There have been no failures documented that also show near zero alignment error.

 

But we should all be aware there may well be some alignment shift (measured vs final) on assembly unless precautions are taken. Stiffness of the alignment measuring system is vital.

 

But recognize also that I have only seen identical R1100 and R90/6 failures, which do not have spline engagement questions.

 

 

[roger 04 rt]

All engines and transmissions are misaligned, it's only a question of how much.

 

Your premise does not follow. At some point of minimal misalignment the spline teeth do not fret against each other, and the spline life becomes indefinite. There may be examples of extended life for a spacer-extended-engagement spline but there are a lot of non-spacered splines that also appear to have indefinite life.

 

On R1150s, every spline application that shows substantial measured error (generally greater than the DIN spec of >.003 TIR), And every one that shows wear, shows serious misalignment. There have been no failures documented that also show near zero alignment error.

 

But we should all be aware there may well be some alignment shift (measured vs final) on assembly unless precautions are taken. Stiffness of the alignment measuring system is vital.

 

But recognize also that I have only seen identical R1100 and R90/6 failures, which do not have spline engagement questions.

 

 

My premise follows well, but you've chosen to only address the convenient points that I've raised. I stipulate that "serious" misalignment will lead to spline joint wear. But the case you presented, shows a lot of crankshaft runout, so much that it is impossible to say what the misalignment is. That's the case in many "documented" measurements.

 

My premise is that there is always misalignment but that it is possible for other factors to exacerbate and amplify what even you would call a "small" misalignment.

 

The problem is there is grossly insufficient data to say what is usual and how much is too much. That would involve not only failed units but bikes that are high mileage with no failure.

 

With your experience and knowledge of mechanics, you would help us all if you could develop a theory to explain scalloped shaft versus linear hub wear, and how the other factors (harmonics, engagement, and initial play between hub and shaft) bear on the results..

 

I'd also appreciate your thoughts on how the two bikes which I mentioned, with three hub and shaft failures between them, have passed high mileage tests, with only additional hub to shaft engagement and zero realignment.

[Andre1150]

well, I picked up a new input spline from BMW, bearings and seals, and I'm machining a spacer for my siebenrock clutch plate to provide full engagement.

 

any advice while I'm in here?

 

and can anyone give me some advice on what to measure in terms of spacers on the input spline.. should I try to match the existing spline?

[dirtrider]

well, I picked up a new input spline from BMW, bearings and seals, and I'm machining

a spacer for my siebenrock clutch plate to provide full engagement.

 

any advice while I'm in here?

 

and can anyone give me some advice on what to measure in terms of spacers on the input spline..

should I try to match the existing spline?

 

Afternoon FireKit

 

As long as you need to take the trans apart anyhow there is no way I would (personally)

re-assemble without measuring the crankshaft C/L to trans front cover bearing bore

mis-alignment.

 

I can't give you much re-assembly advise as I usually set the trans (shafts/housing) up on

my granite plate then use my height gauge to figure & set shaft end play & figure shim thickness.

 

[Andre1150]

ok, good advice. I'm following Chris Harris videos, and making a go of it.

 

what I'm also discovering is the various clutch components as previously installed are also slightly out of balance. ie. the flywheel, clutch pressure plate(s), etc, where the paint marks were, on a balancer, are slightly out of balance. I'm heading to a race shop Monday to get the whole clutch assembly balanced.