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Checking splines / clutch the easy way


Stan Walker

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'02 R1150RT with 69,166 miles on it.

 

Here is what I did and what I observed.

 

1) I pulled the starter to gain access to the clutch area. Easy to do.

 

2) I inspected for anything unusual, like oil. None observed.

 

3) I measured the clutch disc thickness by inserting a stack of feeler gauges between the two pressure plates. By playing with the mix I ended up with a snug fit. I then mic'd that stack (don't add them up) as follows.

0.257" New clutch disc thickness.

0.212" My existing clutch disc as measured above

0.189" BMW wear limit spec from service manual.

Based on the above I have about 34% remaining disc life. That would indicate that I could make it about 100,000 miles on a disc.

 

4) I then taped the clutch lever to the handle bars (fully applied). It is definite that you can see the movement of the clutch pressure plate when applying the clutch. Someone had asked about this.

 

5) I then reached in with a small screw driver and rotated the clutch disc backwards and forwards to observe the amount of play in the clutch disc before the input shaft is made to rotate. In my case this play was about 3/16 of an inch at the outer edge of the clutch disc.

 

Based on the above I conclude that my splines are good and that I have about 30,000 miles of remaining life in my clutch.

 

Any opinions on this procedure are welcome.

 

Stan

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Hey Stan!

 

Interesting...I've never thought of that. Not sure if you can judge the health of the splines or not with that inspection. Certainly it sounds as if you can check the clutch though.

 

I had thought about another way, which is much more involved, but doesn't necesitate removing the whole ass end of the bike...remove tranny bolts one at a time and repace with longer shouldered bolts and simply slide the tranny back to inspect with lights/mirror if necesary. surely some things might need to be removed, but you'd only be sliding an inch.

 

Here's the kicker though; if alignment is critical, and it seems like that might be the major factor in spline failure, how can I be absolutely sure that I properly re-torque the tranny back to the engine case ensuring perfect alignment?

 

Stan, if you can inspect splines that way, it would be ideal. thumbsup.gif

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rotated the clutch disc backwards and forwards to observe the amount of play in the clutch disc before the input shaft is made to rotate. In my case this play was about 3/16 of an inch at the outer edge of the clutch disc.

 

Stan, you have it quite right. This is the method I have been using to monitor my spline wear since I replaced the disk.

 

Let me add some parameters to put the radial play in perspective.

Limits: <1/8 to 1 inch

At almost complete failure the amount of play, measured at the edge of disk will be 1 inch.That is the max, and where mine measured (this is just prior to complete failure).

A new set disk/splines will measure 1/8 inch or less.

In Stan's case 3/16 is good. Mine is at 5/16 with slightly worn splines, and has changed little over the last 5K.

 

Note to Stan's procedure:

There are certain spots around the clutch where this measure is easier than others (the edge of the disk is more accessible).

I use a fine white grease pencil to mark the edge.

When rotating the disk, do it lightly or you be turning the tranny as well. This will give you a larger measure and scare the hell out of you eek.gif

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I had thought about another way, which is much more involved, but doesn't necesitate removing the whole ass end of the bike...remove tranny bolts one at a time and repace with longer shouldered bolts and simply slide the tranny back to inspect with lights/mirror if necesary. surely some things might need to be removed, but you'd only be sliding an inch.

 

This won't work, there's just too much in the way. You can slide the trans/swingarm/final drive back after you lift the back end up.

 

Here's the kicker though; if alignment is critical, and it seems like that might be the major factor in spline failure, how can I be absolutely sure that I properly re-torque the tranny back to the engine case ensuring perfect alignment?

 

The trans is doweled to the clutch housing. Takes care of alignment.

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Let me add some parameters to put the radial play in perspective.

Limits: <1/8 to 1 inch

 

Great info Cali Kid !!! I think you have started something good here.

 

I intend to finish the teardown and replace the clutch disc. It will be interesting to see how well what I find corresponds with this. I'll post once I get it all apart.

 

Stan

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Let me add some parameters to put the radial play in perspective.

Limits: <1/8 to 1 inch

 

Great info Cali Kid !!! I think you have started something good here.

 

I intend to finish the teardown and replace the clutch disc. It will be interesting to see how well what I find corresponds with this. I'll post once I get it all apart.

 

Stan

 

Hey Stan,

 

What a great way of testing this. I am very interested if we can get some corroboration on this as to actual wear compared to measurements.

 

This could save a fortune in repair costs if we can learn to catch this early enough.

 

Are you planning on doing a write-up with photos and specifics?

 

Thanks,

 

Jim cool.gif

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Now, if only somebody could invent a doohickey with which to lube the splines through such a small gap! thumbsup.gif

 

Bugger! I just saw Jamie's post on the other thread... dopeslap.gif

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I am very interested if we can get some corroboration on this as to actual wear compared to measurements

 

First things first. I re-examined my rotational play, my earlier 3/16" was from memory, this time I actually marked a spot and measured the movement. I was wrong, it's closer to 1/8".

 

I've now removed the tranny, pulled the clutch, and cleaned up the splines. I'm happy to report that I can not see any wear on either the input shaft or the clutch disc. Mounting a brand new clutch disc onto the input shaft results in the same amount of rotational play.

 

Here is a picture of the transmission input shaft after 69,166 miles

 

49993318-S.jpg

 

I've posted pictures of the clutch disc splines in a new thread (you'll see why if you read it).

 

I mic'd the old clutch disc. It measures 0.235" thick. My stack of feeler gauges totaled 0.212" so you can see I was way off. 0.023" may not seem like a lot but it is about 33% of the total usable disc material. This means that my clutch is only about 1/3 used up instead of 2/3, and I could expect to get another 140,000 miles instead of only 35,000 before it reaches the wear limit.

 

So why was I so wrong. Well it turns out that there is a small outer lip machined into one of the pressure plates. That plus the accumulated wear of the plates makes the difference. It is interesting to note that this lip didn't exist on my '96 RT. I still have the pressure plates from it and I checked. Oh well, it was a good idea even if it didn't quite fly.

 

Stan

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I have been reading with great interest all the info on the spline lube issue, but have a few questions regarding when to do it. By reading this thread I see that most of you have many more miles on thier machines than I. My 03RT has 11k on it, when should I start thinking of lubing the splines. I got Ted's disc and don't see any real issues in doing the lube, but wondered about the base line. I also have never seen anyone mention the possibility of using a dry spray lube on the splines, such as Molybdenum Disulfide. Would it be possible to apply such a lube through the small accesses available? Thanks DBG

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I have been reading with great interest all the info on the spline lube issue, but have a few questions regarding when to do it.

 

Conventional wisdom is to lube every 40,000 miles, or when you start to have trouble shifting, whichever comes first.

 

I went to about 70,000 miles on both of my RT's because Jan and I ride pretty easy (we're nice to splines). I might have went further on the '02 but "rumors" of the '02's having more than their share of problems coupled with my play at the rear wheel said now is the time.

 

dry spray lube on the splines, such as Molybdenum Disulfide. Would it be possible to apply such a lube through the small accesses available?

 

Some comments:

 

There are 4 sets of splines plus some places on the clutch disc that should be lubed, this would take care of 1 place (the most critical), if it works.

 

Overspray might end up on disc or pressure plates.

 

There is no proof that lubing the splines increases their life expectancy. If the fundamental problem is alignment, materials, or heat treating it will have little effect.

 

Mixing lubricant and clutch disc dust into a goo and using that for lubricant may made a great polishing paste.

 

Stan

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Stan Thanks for the concise reply. Do you know if the splines are lubed during assembly from the factory? I feel I have a little more breathing room now nas my RT shifts like a dream. Thanks again. DBG

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Do you know if the splines are lubed during assembly from the factory?

 

They are supposed to be lubed from the factory. Both of mine were. But the lubricant used has changed down through the years.

 

Stan

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Stan - Fascinating and relieving! Great job. Do you know of any additional differences other than the smaller measurement due to the '96 not having the lip on the pressure plate?

 

Any plans to return to KC for a visit? Thanks. Ron

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Do you know of any additional differences other than the smaller measurement due to the '96 not having the lip on the pressure plate?

 

You mean like:

The 1150 RT clutch is smaller in diameter (165mm vs. 180mm)

The 1150 RT clutch disc (new) is thicker (6.52mm vs. 5.79mm) (my measurements)

The 1150 RT clutch disc wear limit is thicker (4.8 mm vs. 4.5 mm)

 

Any plans to return to KC for a visit? Thanks. Ron

 

No plans at this time to head in that direction, but hope springs eternal.

 

Stan

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Fellas,

 

I took a look at my splines today using Stan's technique. My movement was negligible, less than 1/8 inch on a GS with about 57K miles. clap.gif It is a simple process.

 

I'd love to get some more numbers. Why don't some of you guys go on out to the bikes and take this measurement? You don't even have to take off the starter cables, just the bolts.

 

Hey Stan and Cali, if you don't mind, I'd like to put this info on advrider and see what they think.

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Hey Stan and Cali, if you don't mind, I'd like to put this info on advrider and see what they think

 

I can't speak for Cali, but I certainly don't mind. Let us know if anything interesting is said.

 

Stan

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You don't even have to take off the starter cables, just the bolts

Be carefull not to short out the Hot lead from the battery positive to the frame.

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There is no proof that lubing the splines increases their life expectancy. If the fundamental problem is alignment, materials, or heat treating it will have little effect.

 

Stan

 

Stan:

 

I think you guys are presenting an interesting alternative, but I disagree that lubrication has little effect. In my experience on similar equipment, (like sliding gear couplings), lubrication will nearly always extend the life of the components. Granted if the loads are way too high, alignment too far off or the materials improper, etc. the lubrication may buy a little time if at all. But, if the set-up is acceptable to only moderately wrong, proper lubrication will often make the difference between a quick failure and parts that will operate for a prolonged period.

 

Per Tad_Pole: “Not sure if you can judge the health of the splines or not with that inspection. Certainly it sounds as if you can check the clutch though.”

 

I agree. By the time the splines show wear from this method, the degradation has already occurred. For my time, I’d rather visually inspect and periodically reapply the lubricant. Other shaft driven bikes have a sliding joint, spline lubrication interval. My Concours was recommended every 18.6K miles. Unfortunately on the RT, major disassembly is required.

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Clive Liddell

Terry, you wrote:

"I think you guys are presenting an interesting alternative, but I disagree that lubrication has little effect. "

=======

1. I ask myself the question, then why do all the "other" vehicles in the world with single plate clutches not need spline lubrication?

 

2. A bit of clutch "drag" (which is what a lot of lubers are trying to eliminate) is IMO a GOOD thing since it actually assists in synchronising the engine/gearbox speed to the gear being selected if, of course, you use the throttle properly etc.

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Clive:

 

The Concours sliding joint is a poor comparison to the clutch/input shaft, its not apples to apples. I was thinking that other bikes have a loaded spline in the drivetrain that require periodic lubrication.

 

I agree with your comments, but BMW has an issue that in some cases is causing excessive wear of the splines. Based on what I've read so far (here), I'll attempt to mimimize the risk of failure with a routine that includes maintaining lubrication of the splines. In that sense I think lubrication has a possible effect.

 

P.S. For those that have accumulated sufficient miles like Stan at 69K miles and done the lubrication periodically to conclude he's not likely to have a problem machine, the lubrication may not be as critical.

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