Bad news splines... your input requested ?

[nhmaf]

OK, I *finally* got around to digging into my suspected clutch spline failure problem on
my 82 R65LS, and the "good" news is that my diagnosis was correct.  The bad news
is that my diagnosis was correct, *and* the transmission input splines might also be
damaged sufficiently to warrant repair/replacement.   As I haven't looked at many
BMW tranny splines, I'm asking input from you folks.   If it doesn't look decent/acceptable
(I really don't want to get stranded with another premature failure again) then I'll bite the
bullet and buy a rebuilt transmission and put that in until I get the gumption to rebuild
this one with a new input shaft.

Lesson learned - when buying a bike from someone who left it in "storage" for 15 years,
don't assume that you can just replace all the cables, changing all the fluids and filters, replace
the shocks, rebuild the forks, slap some tires on it, tune it up and ride for 1000 miles before
opening her up to check the splines.   They were absolutely bone dry and there was alot of
rust and metal shavings in the clutch housing when I get her apart this afternoon.

Photos below:
Clutch splines worn down to slightly bumpy inner hub


Transmission input shaft spline closeups for your review/input on acceptability..
They definitely have some peak flattening (not "pointy" triangles in profile) and
the height of the splines "flares" up to about ~ 1mm or so more near the transmission housing.
I can take more photos if necessary.

[Justin B.]

Aack!  They do look to have some height knocked off 'em, probably time to look for a used one.  Here's a shot of the splines from the '82 R100RT tranny I put into my '95:

[Bob_Roller]

Looks like a transmission overhaul, or a second hand transmission purchase is in your future. I guess this could be a poster picture of why spline lubes need to be done on a regular basis, and why this needs to be one of the first projects to take on when you purchase an airhead bike.  I checked on a price for the input shaft, and normal dealer price is $299, Chicago BMW $239, throw in a transmission overhaul for about $4-500, and it's probably going to be more cost efficient to get a second hand transmission. Also $100-125 for a new clutch disc. How many miles are on the bike?

[nhmaf]

I'm exploring a used/rebuilt transmission purchase right now.

The bike only had 14,950 original miles when I bought it, but it
had spent 15 years of its 25 year life sitting in storage.  Apparently
the PO didn't touch the splines or have them done, and I didn't know
this.   I had gone through almost everything else prior to riding it, and was
planning on just riding it the few hundred miles to the National rally in VT,
and back, and short stints around town, before putting her up for the winter
after doing the spline lube this fall.  But, everything went to H-E-double-hockeysticks
shortly after getting back from the national rally.   The odd thing is, it ran and shifted
perfectly well (for a BMW, anyway) right up until the moment of total failure.

A lesson to be learned, indeed !

[Justin B.]

I would pick up a used one.  The one I posted the spline pics from I snagged off e-Bay for $315 shipped.  It was advertised as "recently rebuilt" but no supporting documentation.  I said, "What the hell...", didn't even change any seals, slapped it in, and I've put two winters on it so far...

[Jon_P]

know you went and convinced me i need to do this also. i have no idea other than low miles like yours the shape of my trans is in. look like i will be pulling it out to grease it up.

how long does it take? a day or less? i am going to go search the old posts for this also.

[Bob_Roller]

If you don't have any problems with anything during disassembly, it will probably be an all day job first time around. It all depends on what else you do while you've got it apart this far, clean and lube swing arm bearings, clean and lube the rear brake pedal. Check for any leakage from the rear main seal, oil pump cover seal, get a small mechanics mirror and get behind the flywheel for a look.  Just in case you are curious about the small phillips head screw on the top of the transmission, it holds an oil raceway inside the transmission, remove that screw, and you have to go into the transmission to get it back together again!

[Semper Gumby]

Jon P.

Grease only the splines on the tranny.  The Clymer shows a pic of grease being put on the splines of the hub of the friction plate.  

Read the Snowbum articles before you do this please!  Where is that link....

.. AH HA!

http://pweb.jps.net/~snowbum/techindex.htm

Read carefully ... or suffer!

[nhmaf]

Well, I have a rebuilt transmission and clutch disk, pressure plate, and spring parts on the way.   I have to put in an order
at Bob's or capital cycle to get some new bolts for the clutch and the driveshaft/transmission output
flange, though I think that I'm going to check the final drive splines now before ordering anything else,
in case I have another unpleasant surprise awaiting me. (fingers crossed that I won't have one)...

 [smiley=rolleyes.gif]

I think that the splines would still work if I put the transmission back in, but there would probably be reduced
life span of the clutch disk splines I installed.  Maybe a bit like putting a new chain on an worn out sprocket.
I really hate to do stuff like that, so mainly new/rebuilt stuff is going in.
Well, I've documented the disassembly process with some photos and will do the same on the reassembly, for
the education of posterity, FWIW.  The disassembly process so far has taken about 5 hours, though I've been
taking my time and taking pictures, and the transmission is completely out of the bike at this point.

[Bob_Roller]

Another thing to think about, is what kind of grease to use on the splines. I've got the Honda molylube, and I will use it this time. Previously I used the red BMW grease, and it just doesn't last that long.

[Semper Gumby]

+1 on the Hondamoly.

nhmaf - those are amazing pics.  Thanks.  I wonder how much more I'm going to get out of my "spline".  It was abused by the previous owner but seems to have stopped wearing since I have been greasing it.  I wish there was a grease that was stickyer like the original Starbaug.

[Rob Valdez 79 R65]

kliky on da piky®


 [smiley=1drink.gif]

[nhmaf]

Here is another closeup view of the trans input spline, that gives a better view of how
the height of the splines are worn down.   A new/good unworn spline would be a consistent
height across the width of the spline area on the shaft.   Here you can see a very definite
wear pattern where it ground off all the clutch input splines.   A couple folks have told me
that this can be what splines look like usually after closer to 80K miles or more.  Most all those
rusty and shiny particles on the housing are indeed metal, from you know where..


I also have and use the Honda moly grease specifically for use on transmission/driveline splines
and tractor PTOs, etc.

[Bob_Roller]

I've got just a little under 80,000 miles, and the splines are no where near that worn, I couldn't see any 'step', worn in the splines.

[nhmaf]

You're definitely doing the right thing then, Bob - keep it up and I'm sure it'll go
for many, many more miles !

I think that the mechanic I spoke with was used to seeing customer's bikes with
less devoted/attentive maintenance practiced by owners.