02 RT grind grind grunch.... then coast off the highway

[dirtrider]

Because the spline is already adequate even if not fully engaged - but only providing there is no misalignment. If there is misalignment, all bets are off.

 

Afternoon NRP

 

Bingo-

[Sam Taylor]

Good summary of the theories, D.R. I'd like to add one:

 

The existence of the Overdrive 6th gear. Perhaps the combination of the (slightly) increased torque output vs. the 1100 plus the physics of the 6th gear was too much for the design and/or materials.

 

This dovetails somewhat into the "how you ride it" theory...with the prevailing wisdom being to stay out of 6th until way over 3500 RPM in 5th. At least that's a rule I've been adhering to since my failure, whereas before I was guilty of gearing on up and lazily staying there.

 

Whether this will help or not only time will tell. Still, I have a suspicion that maybe 6th gear as done was not such a good idea....

[greiffster]

BMW has made a lot of running changes during long production runs.

 

The engine was changed from a single spark to a twin spark to reduce light throttle surging & improve runabilty. They weren’t forced to update all the old single spark vehicles. (this is something way more riders were effected by than a few spline failures)

 

They made changes to the final drives & didn't have to update those.

 

They made big changes to the I-ABS after mid 02 & didn't have to recall or update those.

 

Just look at all the transmission internal changes at 8/02 & none of those were forced to be updated on BMW's dime (unless a failure while still under warranty)

 

True, I'm sure that BMW made A LOT of running changes. But, to the consumer, many would be less "important". A change that improves runability is a bit grayer than a b&w design failure of a spline shaft that is just too short.

[dirtrider]

 

As far at the 02 being affected more and other years less, if they really found the problem in 02 I would expect the failures to go away completely and not be reduced only.

 

Afternoon cele0001

 

Depends, I work with the automotive side of this daily & we are never SURE that we have the full problem identified & a fail-proof fix in place until getting field reports back a year or more later that the problem is gone or reduced.

 

Sometimes a running (fix) or update brings on more problems than it eliminates.

 

 

[dirtrider]

Good summary of the theories, D.R. I'd like to add one:

 

The existence of the Overdrive 6th gear. Perhaps the combination of the (slightly) increased torque output vs. the 1100 plus the physics of the 6th gear was too much for the design and/or materials.

 

This dovetails somewhat into the "how you ride it" theory...with the prevailing wisdom being to stay out of 6th until way over 3500 RPM in 5th. At least that's a rule I've been adhering to since my failure, whereas before I was guilty of gearing on up and lazily staying there.

 

Whether this will help or not only time will tell. Still, I have a suspicion that maybe 6th gear as done was not such a good idea....

 

Afternoon Sam

 

If the spline wear was straight along the spline or there was a lot more brinelling showing on the spline interface then

I would be more inclined to agree with your 6th gear theory.

 

From the spline failures (& pre-failures) I have personally seen, & most of the on-line posted failures or impending failures that I have seen posted, it looks to me like a wiping type angular wear more in line with a misalignment than a piston pulse type wear pattern.

 

No doubt in my mind that hammering along in 6th gear at 1800 RPM's is possibly accelerating the wear slightly but I don't (personally) believe that to be the root cause of the BMW 1150 spline wear problem.

 

[roger 04 rt]

I don't buy the 6th gear theory or low-rpms high torque. The horsepower and torque required to cruise, in any gear, are well below the engine's potential. For example, let's says you chose to cruise in 6th gear at 40 MPH, which is about 2000 RPM. Here are the numbers:

 

Power Required: < 4 horsepower

Engine torque required in 6th gear: <10 lb-ft

Engine torque required in 4th gear: <7 lb-ft

 

However, if you want to stress the input shaft and clutch hub, accelerate to redline at WOT. In that case, you load the clutch hub and input shaft with about 70 lb-ft torque in any gear. That's a way to put a real-man's load on the shaft.

 

 

[dirtrider]

Afternoon Roger

 

I think the basic thought on 6th gear spline wear is more down the lines of 2 cylinder low RPM power pulse hammering than torque demands.

 

You see low RPM gear tooth hammering & driveline hammering related wear in a lot of old John Deere 2 cylinder tractors.

 

 

[mneblett]

D.R., what do you think of this idea:

 

Maybe this is not a problem with the engine/trans alignment, but with the tranny's front bulkhead plate being mis-machined. I'm wondering whether it is possible that the input shaft bearing seat was being (randomly?) mis-machined slightly to one side -- for example, if worn machine tooling was sometimes allowing the bearing pocket to be laterally displaced enough to angle the input shaft relative to the engine/clutch hub.

[dirtrider]

Afternoon Mark

 

Sure, anything is possible when it comes to total input shaft alignment.

 

That could easily be one of the items that slips a little as tooling wears or ???

 

I do know a couple riders that replaced the trans front housing & (according to them) that eliminated spline wear. No way of knowing if the new housing corrected bearing placement, or alignment pin position, or angular housing alignment, or all as a package.

 

I have a distant friend (long time BMW tec) that thinks the problem was maybe due to shipping the bikes in a crate. According to him the way that the bike was chocked & tied down in the shipping crate was changed in late 02 or early 03 & about that time his shop saw reduced spline failures on new bikes. (the bike has no front wheel installed for shipping)

 

His thought is/was that if the crate was dropped, or set down hard, in transport that it could bend the trans front housing. (I tried to pin him down more but he tells me he can't remember exactly the difference as he was always busy & mostly the other dealer help usually uncrated the bikes when they came in.

[Sam Taylor]

That's a way to put a real-man's load on the shaft.

 

 

I'd love to have a little fun with that, but will stick to the science--and yours is good.

 

Still, while the theories for spline failure cause were being laid out, I wanted to add this as a possibility because it is a major differentiator.

 

When I stripped my splines, I was riding on Interstate 80 headed up into the Sierra, about 10 miles west of Truckee. I was loaded for bear with full bags and full gear. I was in 6th, doing about 65, and rolled on to make a pass. Should have downshifted, but was distracted and lazy.

 

"Stttttttrrrrriiiiiippppp!"

 

So I'm stuck with series of events in my mind. Realize that it's happened to others in different ways.

 

 

[nrp]

The only spline strip out I've actually witnessed and measured the run out was on a '99 R1100RT. That was documented in this forum in June 2011 when I built that measuring fixture.

 

Of course there is also the identical spline strip out of my '75 R90/6 about 20 years ago. Only we didn't have this forum then & I didn't really know what I was looking for.

 

There was no direct way to measure the '75 R90/6 run out, but when I relubed it again about 2 years ago, I loosened the engine-transmission bolts while it was running & could definitely feel the wiggling at the interface. From repeated clutch engagements, I could not eliminate that wiggling so I just finished it up as is. I don't drive it that many miles anyway.

[Stan Walker]

If low RPM running was the cause I would have trashed my splines many times. I often run in 6th gear at sub 3000 RPM. Around town I usually have up-shifted by 3500 RPM.

 

If early R1150RT production was an issue my bike would be a prime candidate. My build date is Jan 2001.

 

Instead, my bike is at 129,000 miles on the original clutch disk and original tranny input splines. The splines were cleaned and lubed around 60,000 miles ago using the Honda moly stuff. They showed almost no wear at that time. A check of clutch disk rotational free play done through the starter hole some time after that indicated all was still good to go.

 

Assuming that both I and the bike are still operational after this years riding season I intend to inspect/re-lube the splines again.

 

 

[roger 04 rt]

Afternoon Roger

 

I think the basic thought on 6th gear spline wear is more down the lines of 2 cylinder low RPM power pulse hammering than torque demands.

 

You see low RPM gear tooth hammering & driveline hammering related wear in a lot of old John Deere 2 cylinder tractors.

 

 

Hi DR, Hadn't heard that one but have read many posts concerned with lugging the engine. While it is possible to lug the 1150 engine, my senses tell me that I never get near to it.

 

Regarding the pulses, isn't that what the input-shaft spring-loaded device (not really a damper) is for?

RB

[roger 04 rt]

J

That's a way to put a real-man's load on the shaft.

 

 

I'd love to have a little fun with that, but will stick to the science--and yours is good.

 

...

 

 

Touchè

[dirtrider]

Afternoon Roger

 

I think the basic thought on 6th gear spline wear is more down the lines of 2 cylinder low RPM power pulse hammering than torque demands.

 

You see low RPM gear tooth hammering & driveline hammering related wear in a lot of old John Deere 2 cylinder tractors.

 

 

Hi DR, Hadn't heard that one but have read many posts concerned with lugging the engine. While it is possible to lug the 1150 engine, my senses tell me that I never get near to it.

 

Regarding the pulses, isn't that what the input-shaft spring-loaded device (not really a damper) is for?

RB

 

Afternoon Roger

 

You are probably a lot less likely to get lugging like hammering as you have a twin spark (that does help the low RPM combustion) & you are running a fueling modifier & that again helps low RPM lugging.

 

Go find yourself a stock 1150 single spark & you will see what low RPM lugging feels like.

 

That input shaft dampener does help but it sure can't eliminate all lugging induced hammering.

 

Just put most idling warm single spark 1150's in neutral & listen to the gear rattle. That is due to the 2 cylinder power pulses rattling the gears & sliders.

 

[roger 04 rt]

Afternoon Roger

 

I think the basic thought on 6th gear spline wear is more down the lines of 2 cylinder low RPM power pulse hammering than torque demands.

 

You see low RPM gear tooth hammering & driveline hammering related wear in a lot of old John Deere 2 cylinder tractors.

 

 

Hi DR, Hadn't heard that one but have read many posts concerned with lugging the engine. While it is possible to lug the 1150 engine, my senses tell me that I never get near to it.

 

Regarding the pulses, isn't that what the input-shaft spring-loaded device (not really a damper) is for?

RB

 

Afternoon Roger

 

You are probably a lot less likely to get lugging like hammering as you have a twin spark (that does help the low RPM combustion) & you are running a fueling modifier & that again helps low RPM lugging.

 

Go find yourself a stock 1150 single spark & you will see what low RPM lugging feels like.

 

That input shaft dampener does help but it sure can't eliminate all lugging induced hammering.

 

Just put most idling warm single spark 1150's in neutral & listen to the gear rattle. That is due to the 2 cylinder power pulses rattling the gears & sliders.

 

Hi DR,

I defer to your vast experience on this but wonder if the noise created is a meaningful indicator of possible wear.

 

I agree that the torque pulses are quite high in a two cylinder engine. Most of the torque is provided by 10% of each engine rotation. Meaning that the peak torque is 10-20X higher than the average engine torque.

 

However, does the torque pulse wear exhibit itself at average torques of 10 ft-lbs?

 

I know many riders love the exhilaration of all-out acceleration but it comes with a very high average torque load, maybe 10X the cruising torque. That would mean peak torque pulses of perhaps 1000 lb-ft.

RB

[dirtrider]

 

 

 

Just put most idling warm single spark 1150's in neutral & listen to the gear rattle. That is due to the 2 cylinder power pulses rattling the gears & sliders.

 

 

I defer to your vast experience on this but wonder if the noise created is a meaningful indicator of possible wear.---The neutral gear rattle is pretty normal even on new bikes. Just a side effect of all those gears in constant mesh & the sharp power pulses of a high compression 2 cylinder engine with not much flywheel weight. On the early 1100 5 speed's BMW added rubber "O" rings at the gears to shaft's interface's to stop (or reduce anyhow) neutral gear rattle. That actually worked but it did seem to hinder smooth gear shifting so on later gear boxers the "0" rings were eliminated & BMW just posted a bulletin that gear rattle was normal. Auto makers fight with the same neutral gear rattle on 3 & 4 cylinder automobiles & especially diesel engine manual trans vehicles.

 

I agree that the torque pulses are quite high in a two cylinder engine. Most of the torque is provided by 10% of each engine rotation. Meaning that the peak torque is 10-20X higher than the average engine torque.

 

However, does the torque pulse wear exhibit itself at average torques of 10 ft-lbs?--- I believe it would. The torque carried by the spline joint is one thing but the spline size/length/material has probably been well calculated by the trans/clutch design team. In a way higher (constant torque) would probably be a lot easier on the spline joint than lower hammering torque. It isn't the loads that damage the splines it is (constant) hammering on low RPM piston firing.

But, like I mentioned in another posting above, my personal belief (as well as the belief of many others) it isn't the lugging or torque load carried that are wearing the 1150 boxer splines, it is wiping or orbital wear from a mis-alignment issue. There is no doubt in my feeble engineering mind that lugging (hammering pulses) could contribute to early spline wear but to me the lugging induced wear would be a very small part of the overall spline wear package.

 

I know many riders love the exhilaration of all-out acceleration but it comes with a very high average torque load, maybe 10X the cruising torque. That would mean peak torque pulses of perhaps 1000 lb-ft.--- If high or higher mean torque loads through the splines increased spline wear then I would probably get 10,000 miles on the splines in any of my bikes. I ride them hard (not just once-in-a-while but probably closer to "mostly". I seldom ever return home without my GPS recording triple digit top speeds & if a recorder was put on my TPS it would show a great number of WOT's on every ride.

 

I (personally) owned (2) brand new 2002 1150RT's, one wore the splines (completely stripped) at under 30K, the other almost same bike but different color went well over 150K, & still going last I knew, (new owner for last 75K) with original trans, clutch, & splines so I obviously I didn't kill the splines in my 75K part of the riding. (both bikes ridden almost identically on my part of the riding).

[speedybee]

There are many theories as to what contributes to premature spline failure. How about surging? This Chris Harris video makes sense to me. Good news...ride hard if you don't want your splines to fail.

 

[TripleThreat]

 

I (personally) owned (2) brand new 2002 1150RT's, one wore the splines (completely stripped) at under 30K, the other almost same bike but different color went well over 150K, & still going last I knew, (new owner for last 75K) with original trans, clutch, & splines so I obviously I didn't kill the splines in my 75K part of the riding. (both bikes ridden almost identically on my part of the riding).

 

There we have it... It boils down to the color of the bike!

[nrp]

Repeating from earlier postings on this. Think of a spline as a 1:1 internal/external gear that wont wear providing there is no relative motion. But if there is any misalignment that can't be accommodated by shaft deflections etc, there will be relative motion - 1/rev - that will fret the spline.

 

And that would be a darn small gear to be handling engine torque and speed with no positive lubrication.

 

Another reckless analysis - To those that say the spline simply isn't long enough - consider a 3/8" hex key in a socket head cap screw that can easily take 70 ft lbs torque. The surface loadings are probably more than 100 times our spline loadings (1/3 the diameter, 1/6th the length, 1/3 the surface unit loading due to the hex, and maybe 1/5 times the number of teeth. Multiply it all together & it's like less than 1% of the unit loading on our splines.

 

So why do our splines fail? It is the number of unnecessary fretting cycles spent dragging (maybe 1000 lbs to drag the disk) the clutch disk around the flywheel 4000 times every mile. It has little to do with driving habits - it only requires the engine to rotate with the clutch engaged.

[dirtrider]

There are many theories as to what contributes to premature spline failure. How about surging? This Chris Harris video makes sense to me. Good news...ride hard if you don't want your splines to fail.

 

Afternoon speedybee

 

If surging killed splines then there would be a very large number of 1100 boxer bikes that trashed splines. They didn't & some surged like crazy.

[speedybee]

There are many theories as to what contributes to premature spline failure. How about surging? This Chris Harris video makes sense to me. Good news...ride hard if you don't want your splines to fail.

 

Afternoon speedybee

 

If surging killed splines then there would be a very large number of 1100 boxer bikes that trashed splines. They didn't & some surged like crazy.

 

DR,

 

If you have not already, watch the full video.

 

The way Chris explains it in the video it is because of the lower typical RPMs of the six speed tranny compared to the 1100s five speed. The 1100s, with a five-speed tranny, are not lugged as much. The six speed, with a combination of lower RPMs/lugging, and the surging issues, are causing the spline wear. This seems plausible to me and it may explain why the twin sparks, which surge less, report fewer spline failures.

 

 

 

 

 

 

 

 

 

 

 

[dirtrider]

This might of interest to this thread--

 

Below is a part of a BMW service bulletin pertaining to early or abrupt spline failure in BMW K bikes.

 

[roger 04 rt]

That pretty much says it all.

[roger 04 rt]

BTW, I caught your comment about the transmission housing possible being deformed due to a weak shipping container. Although not proven, that makes a lot of sense as a possible cause.

 

I always found it somewhat hard to believe that a company that machines things for a living might have had such variability. Especially given that they know that an alignment of 0.25mm or better is needed for long interface life.

[dirtrider]

Afternoon Roger

 

My personal opinion is that .25 mm (almost .010") is BMW engineering giving BMW service a LOT of wiggle room.

 

.25mm is a LOT of mis-alignment for a spline joint to have a long & happy working life.

 

 

 

 

 

 

[nrp]

I'd think 0.1 mm TIR would be more appropriate. That just happen stop be DIN specs for this type of application too.

 

And I understand European oilheads have this problem too.

[roger 04 rt]

When I ran some numbers, 10/1000" seemed like a lot. It puts a huge orbital pressure. For example if the misalignment is such that the transmission centerline is directly below the engine centerline then the 12/6 o'clock teeth are up/down but the 3/9 o'clock teeth are shifted side to side, leaving the inboard 3 o'clock hub tooth only contacting the shaft the point of spline shaft wear, near the transmission. And the 9 o'clock hub tooth being worn by the end of the shaft tooth.

 

It's a little hard to see without a diagram but as you mentioned this is a continuously wearing pattern of the teeth going up and down, and in and out, while the shaft spins.

[roger 04 rt]

One big potential benefit of a longer engagement is less play in the hub to shaft connection.

 

For example, if the hub and shaft were completely tight it would be harder for wear to start since there could be almost no relative motion.

 

For wear to take place it seems there needs to be work done over a distance. If you want to sand something, the sandpaper has to move. If the joint had no play then something else would give, I guess.

[dirtrider]

 

Afternoon Roger

 

One big potential benefit of a longer engagement is less play in the hub to shaft connection.--Maybe, if the disk to shaft has .001" clearance that would still be .001" even with a longer shaft. (this is with a fairly well centered spline joint). If the alignment was off to begin with then it would be a tighter fit with a longer shaft but the longer shaft would put more working bind on the spline joint possibly causing more wear to take place. The clutch hub to input shaft needs a working clearance to allow clutch disengagement so with a mis-alignment the spline joint turns into a basic gear set with the added problem of the VERY SAME teeth ALWAYS meshing to each other & no flowing lubricant to or on the tooth mesh.

 

For example, if the hub and shaft were completely tight it would be harder for wear to start since there could be almost no relative motion.--True but then the disk couldn't slide freely on the splines during de-clutching so shifting would be very difficult.

 

For wear to take place it seems there needs to be work done over a distance. If you want to sand something, the sandpaper has to move. If the joint had no play then something else would give, I guess.--If the joint had no play it wouldn't de-clutch & you wouldn't be able to put the bike in gear with the engine running. I suppose that could increase spline life as the bike would be about un-ridable.

[dirtrider]

Evening Roger

 

I posted this about a year or two ago but it might be worth posting again.

 

"A few years ago when the early BMW 1150's were failing clutch splines just a bit slower than their tires were wearing out I had a long talk with one of the very experienced engineers from the powertrain development area of the company I work for. I had worked with him a few times on some oddball drivetrain wear issues & he was a wealth of knowledge on component wear issues. He worked for years with the heavy duty truck & large power units. He also had years of spline coupling experience working with PTO spline related issues.

 

First thing he said was-- lets start by isolating the clutch part from the spline part.

 

Basically in a nut shell-- he told me that in a properly aligned splined coupling, there should be no sliding contact. The spline contact should basically be compressive only.

 

But, if there is any misalignment between the spline attached components then a sliding contact in a splined joint could occur. His simple explanation was like continually meshing gear teeth.

 

But even worse (or in addition) an angular misalignment of the spine joint can produce an oscillating type movement in the mating spline teeth.

 

So my obvious question was how about lubrication? Will that help if there is a misalignment or angular aliment problem. His reply was "sure it will help", but only if you can continually keep it lubricated. He said there were cases where they had used continuous lubrication to cure spline wear issues that couldn't be cured with better alignment or using a larger spline joint because of packaging, real-estate, or flexing components (that was referring to running the joint in an oil bath).

 

So, I asked how often should the joint be lubricated if it couldn't have a continuous lubrication system. He said with a misalignment or angular alignment issue it is difficultly to say without durability testing or field testing but probably at least once a week might be enough for something like frequent motorcycle usage & maybe once a month for occasional usage.

So my next question was, is some lube once in awhile better than none. Again that same answer of "can't really be sure without testing or frequent disassembly evaluations". He did say that an occasional greasing could actually make the problem worse if the grease holds any metallic wear particles in suspension at the spline contact area. According to him part of the advantage of frequent joint lubrication is that it flushes the abrasive wear particles out of the spline joint.

 

He wasn't familiar with the BMW 2 cylinder (or motorcycles in general) so I mentioned that the BMW in question has 2 cylinders firing at 360° with rather harsh power pulses. Ah, he said you thinking maybe fretting from the engine pulses. I said the thought crossed my mind. Could be, he said, is the spline wear rough or smooth. I said pretty darn smooth & quite angular looking. He said that looking at the wear debris could tell a story but the smooth wear didn't point to fretting or at least fretting as the major cause.

 

He also mentioned the 3 major concerns with spline joint life are: alignment, alignment, alignment."

 

[Jim Moore]

That's interesting, DR. Thanks. IMo the misalignment threory is spot on. It is interesting to speculate on how it happened, but it's not going to solve the problem. The only real question in my mind is what effect Cele's spacer would have on a known bad transmission. There's a guy on the pelican parts r1100s board who just put his bike back together with a bad tranny using a spacer on the clutch disc. Gonna be an interesting experiment.

 

Actually another question just occurred to me. iis the misalignment always the same? I heard a theory once that one of jigs used to hold the transmission in place was a little out of whack. I don't know the particulars, but that seems to fit my theory. If so, maybe all the bad ones are misaligned the same amount. If so, maybe someone could make a little money by machining the offset dowels. It would only take a few measurements to convince me one way or the other. I have a bad tranny in the garage. Unfortunately, I don't have the skills to get an accurate measurement. I prolly have the skills to split it in half and Mail the front half of the case to someone who does have the skills. Anyone feel like doing that? I think five or six bad ones would probably give us a good idea.

[dirtrider]

Morning Jim

 

You are right, lots of speculation on the "WHY" of the misalignment issue.

 

At this time in history, with all the 1150's out of factory warranty, it probably doesn't matter. Some fail & if you have a failure prone bike then it is-what-it-is.

 

It would be nice to measure up your front housing but without the CORRECT machining specifications it wouldn’t tell us anything.

 

I suppose we could generate some useful data if we had a KNOWN GOOD front housing to compare it to (anybody have a 100,000+ mile 1150 transmission with pristine splines they are willing to pull apart ?

 

So far the only way I have had to check the front housing alignment is to have the (bare) housing bolted to the engine it came on & sweep the front bearing bore from the engine crankshaft. Even then that doesn't show angular mis-alignment & that (angular alignment) is probably part of the issue.

 

Even if we knew the offset of the trans to engine, then took an average offset from a few front housings & made off-set alignment pins, that wouldn't be a straight forward bolt-in. There are only 2 alignment pins & so they would have to be clocked perfectly to center the trans on the engine.

They only way to clock them perfectly is to bolt the front cover up with the off-set pins then sweep the bearing bore while turning the pins to reduce or eliminate the mis-alignment.

 

It is a LOT of work to check & correct the trans to engine alignment (probably the reason most repair shops won't even attempt it)

 

I have played with the thought for years (haven't tried it yet though) is to try centering the trans like we did on the old airheads. Remove the alignment pins then try centering the trans with the engine idling by loosening the attaching bolts & allowing the trans to self center on the clutch. The thing that has me a bit worried in trying this is; first the much heavier mass of the 1150 transmission & the 1150 transmission weight offset from center. Would probably have to rig up some bungee cords to hang the trans from to neutralize most of the weight & to bring the offset weight to centerline.

 

Added: the "all the bad ones being off the same amount" is not likely to my way of thinking. You would think that if they were all off the same amount then they would all fail reasonably close to the same miles. Some fail at 22,000 miles others in the 30,00 mile range & some go 50,000 or more before failure.

 

 

[nrp]

I don't think there's any serious angular misalignment as it is so easy to check. Radial misalignment requires disassembly of the transmission innards and a sweep with a dial test indicator. The working space is so small that many commercial setups will have so much compliance in the measurement fixture that the readings are worthless.

 

In addition, I suspect the rear crank bearing becomes worn if there is a radial alignment error. That would make an indicator sweep impossible to interpret.

[Redman]

Good discussion.

I am reading and studying it.

 

If someone isn't familiar with it, here are pics of my bike.

 

 

.

I would say "angular misalignment". But maybe "radial misalignment" for all I know. Anyway, not rebuilding this xmission.

 

.

 

 

[PAS]

There sure appears to be a lot of metallic flakes scattered around. I wonder if a magnet could be slipped in with the starter removed to see if that is happening.

[AndyS]

I don't think there's any serious angular misalignment as it is so easy to check. Radial misalignment requires disassembly of the transmission innards and a sweep with a dial test indicator.

Hi nrp.

I am of the school that says the issue is definitely some alignment issue.

However I am not convinced if it is radial or angular.

 

Manu of the photo's I've seen show a longitudinal wear pattern on the splines (pointing toward radial misalignment), but some, like Redman's show a helical wear pattern which smacks of linear misalignment?!

 

 

 

 

 

[Redman]

There sure appears to be a lot of metallic flakes scattered around. I wonder if a magnet could be slipped in with the starter removed to see if that is happening.

 

 

Ah.... remove starter....?

 

 

Oh, you mean on any running bike, as a diagnostic test.

 

Although, I suspect a lot of the "metal flakes" that can be seen are from the final catastrophic failure.

 

.

[Twinsig]

"I suppose we could generate some useful data if we had a KNOWN GOOD front housing to compare it to (anybody have a 100,000+ mile 1150 transmission with pristine splines they are willing to pull apart ?"

 

I have exactly that but with only 80k, perfect splines already disassembled! Its waiting for me to finish up some major home remodeling projects.

 

My current Trans has 127 that is, if the PO bought a brand new one when the orig got stuck in second gear.

IF ? someone is willing to take the time for this effort I'll loan the case for 90 days or so.

[JamesW]

And you wonder why BMW finally went with a wet clutch, FINALLY!!

 

If only the wethead had good looks.

[AndyS]

Good afternoon James. There is NOTHING AT ALL wrong with dry clutches.

They serve the motor and agricultural world VERY well.

Obviously many (most) dry clutched handle WAY more power and pulsing loads than the wee 1150RT puts out.

Wet clutches are not exempt problems.

The issue here is a manufacturing/design flaw.

We shouldn't have a knee jerk reaction to this and throw the baby out with the bath water and condemn the simple Dry Clutch design.

[dirtrider]

 

I have exactly that but with only 80k, perfect splines already disassembled! Its waiting for me to finish up some major home remodeling projects.

 

My current Trans has 127 that is, if the PO bought a brand new one when the orig got stuck in second gear.

IF ? someone is willing to take the time for this effort I'll loan the case for 90 days or so.

 

Afternoon Twinsig

 

That sounds like a fantastic & workable offer.

 

I'm thinking the best way (for me anyhow) to verify/compare those front housings is to set them up on my Bridgeport table, dial indicate the center bearing hole for X,Y,Z (0) datum point, then use the 3 dimensional digital read out to plot the alignment pins X/Y positions, then use the Z readout to do a perimeter Z height on the rear housing face for angular out-of-plane.

 

Problem is, my Y readout is presently broken & I have been waiting on parts for a month now. They promise "soon" but I have been hearing that for a while now.

 

Once I get the digital repaired & calibrated I have some 80% lowers to run off then I will be open to look at the BMW housings.

 

I'll let you know when I'm back up running & calibrated then we can see if it is still within your time frame for the housing loan-out.

 

[greiffster]

I'm thinking the best way (for me anyhow) to verify/compare those front housings is to set them up on my Bridgeport table, dial indicate the center bearing hole for X,Y,Z (0) datum point, then use the 3 dimensional digital read out to plot the alignment pins X/Y positions, then use the Z readout to do a perimeter Z height on the rear housing face for angular out-of-plane.

 

 

But, actual data is much less fun than conjecture and speculation.

 

 

[dirtrider]

 

But, actual data is much less fun than conjecture and speculation.

 

 

Afternoon greiffster

 

There would still be plenty of wiggle room for "conjecture and speculation" as the data would only reflect the transmission side. There is still the engine side, both angular, radial, & rear main bearing displacement that we wouldn't have hard data for.

[Twinsig]

Dirt,

 

No prob, time limit is flexible, unless my current trans craps out! knock-on-wood..(which I spline-lubed summer of 13, also perfect)

 

I'd planned on using that one for a BETA rebuild/my first and leave current trans ALONE,,, just in case I screw it up.

 

gimme a shout when you're ready

[roger 04 rt]

 

But, actual data is much less fun than conjecture and speculation.

 

 

Afternoon greiffster

 

There would still be plenty of wiggle room for "conjecture and speculation" as the data would only reflect the transmission side. There is still the engine side, both angular, radial, & rear main bearing displacement that we wouldn't have hard data for.

 

Earlier in the thread DR, you mentioned the hypothesis that the transmission housing might have been bent in shipping. On a casting of that type how much deformation is possible before the housing would show cracks?

[nrp]

I don't think there's any serious angular misalignment as it is so easy to check. Radial misalignment requires disassembly of the transmission innards and a sweep with a dial test indicator.

Hi nrp.

I am of the school that says the issue is definitely some alignment issue.

However I am not convinced if it is radial or angular.

 

Manu of the photo's I've seen show a longitudinal wear pattern on the splines (pointing toward radial misalignment), but some, like Redman's show a helical wear pattern which smacks of linear misalignment?!

Longitudinal wear and helical wear can both happen with only radial misalignment. Which you get depends on the hardness difference profile between the two parts.

 

I think this spline system would be fairly immune to minor angular misalignment since there is a thin flex plate between the clutch disk and the hub. Gross misalignments would fail that flex plate in bending fatigue.

 

On the other hand, that flex plate is radially very stiff and will readily support the ~1000 pound forces needed to drag the clutch disk around the flywheel face.

[nrp]

DR - ypu've been holding out on us if you have a Bridgeport with digital readout.........

 

Note though that to get the true axis of the transmission, you will have to dial indicate on both the input bearing housing and the rear bearing housing ID before looking at the alignment pin holes. Either that or make a mandrel of sorts.

 

I would expect that since this casting is done in a Cartesian coordinate (X and Y) boring machine of some sort, that the location of the alignment pins with respect to the transmission axis would be an even millimeter metric measurement, rather than angle based.

 

But even if we recreate the correct alignment pin measurements, for field fixes wouldn't it be easier to just sweep that transmission bore with respect to the crankshaft to eliminate any fixture errors?

 

I think if we made offset alignment pins, they could be marked with the high side for any bike that has been indicator swept.

 

Of course if there was a way to do it without disassembling the transmission that would be much better. A split thin wall sleeve slipped over the input shaft splines would allow allow a similar measurement, but it would require the clutch disk to be removed. Of course it usually has to come out anyways.

 

Just thinkin!.....

[dirtrider]

 

Earlier in the thread DR, you mentioned the hypothesis that the transmission housing might have been bent in shipping. On a casting of that type how much deformation is possible before the housing would show cracks?

 

Afternoon Roger

 

That hypothesis came from a BMW tec friend of mine.

 

I really have no idea how much deformation before cracking showed up, would probably take a bending test to even make a guess.

 

As you can see the front housing is unsupported in big part of the lower & the a lot of the rear trans case support is off center.

 

To me it sure is possible they were bending a little if the bike was supported in the shipping crate with vertical support (chocking) under the trans front case area & the shipping crate was dropped. (they were shipped with no front tire installed)

 

I actually saw a 1200RT create dropped out of a delivery truck when the forklift forks slipped out.

 

[nrp]

Another thought - There will be plenty of magnetic dust inside the BELL housing of any worn spline system.

 

Based on my 2000 R1100RT though, a truly pristine spline is very clean and not grundged up with black crud like all these failed photos show.