gearbox worn out?

[botus]

I just realised the death noise on the centre stand of the rear bevel is in fact the top 3 gears rumbling - is this normal at 37k miles ?

on the road riding its dead silent - but chugging in gear on the centre stand its like the world is ending. I used to think it was the rear bevel (and indeed it needs a bearing for small amount of slop on the wheel vs swinging arm), then someone said the angle of dangle for the UJ makes it struggles so they complain on the centre stand and you shouldn't do it (and my after market shock unloaded is 1/2" longer so will make it more of an issue...)

then two events and made me change my mind about the bevel or the drive shaft...

1) 8 weeks back going round the M25 for 100 miles each way - when I came to stop the gearbox felt nasty, the upper gears didn't like to change in or out of 5th and 6th (scary as it should have the right level and been changed often enough), the lever was stiff to operate and selection was all wrong - since gone away but it was clearly upset then !
2) when the CAT sensor went mad and I was trying to see live data info running on the stand with the GS911, I realised this hideous racket is much worse in 6th, bad in 5th and 4th, then nothing like the same in 1st, 2nd or 3rd even if the speedo is giving the same road speed
3) even dragging a load with the rear brake doesn't calm it down at all in 5th and 6th - and the rear wheel rotational backlash slop isn't stupid in 1st

It needs a clutch (and the stupid swinging arm bearings) - the one bit of good news, I got hold of a low mile box a while ago, as years back I thought 2nd to 3rd shift was nasty after it went over off road, (yet I'm sure the lever never hit the ground). This other box has only got 6k miles on a complete box - and I got it for less than a couple of gears and some selector forks would have cost from BM - but being a tart, its not as pristine as my current casing - and not keen to pull it apart, not got the space or any special tools I might need....

is it common (I guess) that the main shaft bearings fail ? might explain why the oils on the clutch ?

anyone have a clue what bits its likely to be ?

https://www.realoem.com/bmw/en/partgrp?id=0307-EUR-06-2007-K25-BMW-R_1200_GS_04_0307,0317_&mg=23

 

[Flintlock]

Think it's advised not to run the bike through the gears when up on the centre stand. I know next to nothing about how it all works tho - as Oddball says 'I only ride them, I dont know what makes them work'

 

[mikeyboy]

Drain the oil,
If the bearings are buggered it should be fairly obvious.

 

[botus]

found the old trans oil from years back - it had separated the dirt till it was looking like new, with only a smidge of grey filth in the bottom corner of the bottle - I guess this must have been a fill BMW did circa 12k, and I guess I did it again around 24k, using bmw dealer supplied castrol long life 75W / 90 GL5 synthetic - its now £35 a bottle at the stealership !!!

37k miles box warm, drained mine yesterday - I figured it was pretty clean as the fist stuff came out - left to drain overnight and its actually pretty filthy - can't see bottom (but had used a dark tray...)
Tipped a bit out and its got a pretty heavy grey tinge to it - ran a magnet in there and got nothing - seemed to get >850ml out. Tipping most out found a few sparkles but then had some pretty horrific missed gears and fake neutrals (just this year I had my worse ever noise with a crashing re-engagement - so really expecting far more wouldn't be much surprise). That said don't miss many gears these days and I used to lots more years back, so its a little odd its really the first time seen any bits. Might try and get a photo its naff all really.

To have that really stiff / odd 5th and 6th gear change issue after a 100 miles run, I could have envisaged much more, and that racket in the upper gears on the centre stand makes a cement mixer sound refined. So a bit perplexed at the cause. Gear change is back to normal - no evidence of anything except my knowledge it was really wrong - it was 2 months back on that one ride (in the dry) in 5th and 6th the lever was super stiff and engagement very laboured and awkward. Lower gears felt normal - I went up down and around multiple times as I went in to chelmsford, but it remained nasty in those two upper gears - But now thinking on the way home I never had an issue - in fact I had even forgotten it happened - after that test ride all I was thinking was how the hell anyone rides with a bridgstone front tyre.

today poured a bit of the old clean stuff in there to swill out any dregs, and used budget nasty coma 75W / 90 GL5 semi-syn at only £9.50 a bottle !!! this stuff is much thinner than the stuff BM had in there from years back. Maybe there's something - I remember after dropping it off road, second felt all stupid and the change up was never as nice in any gear - but the weird bit was the lever never touched the ground (the only damage was a hand guard bracket, wasn't even any cosmetic scuffs and I questioned if it was more my head looking for issues) - but it was there, the change up issue was why I got hold of the spare box - it had a kind of double notch into 2nd and 3rd, but oddly that's all vanished after 2 years and it feels as good as it always had....

question on quantity for the refill: one bod says 800ml, the manual says nothing on spec or capacity (nice), so tipped in 850ml figuring half will be left around the funnel and the poring container - it isn't even dribbling out, then found this site saying

Gearbox 0.70l > 0.90l (SAE 75W-90 Hypoid gear oil) **Fill oil to bottom edge of filler hole as different year models have varying oil quantities!

R1200GS (K25) – Munich Motorcycles

www.munichmotorcycles.com.au

the real question - does overfilling cause the issue with gearbox seals leaking all over the clutch ? On a ford focus the level is supposed to 1/2" below the level bung - (which is really dim), but now I wonder if BM play such a game ?

 

[botus]

found a BM manual this gearbox 900ml till it dribbles out...

so this is brilliant - I've now put in 1000ml and with a powerful torch I can see its 2 mm below the thread of the filler bung ???

 

[gazza12adv]

I use a litre bottle to do final drive and gearbox at the same time. I use a syringe to fill final drive with 180ish ml's then use the rest in the gearbox. Been fine liked that. Stop overthinking it.

 

[Santa-2512]

I use a litre bottle to do final drive and gearbox at the same time. I use a syringe to fill final drive with 180ish ml's then use the rest in the gearbox. Been fine liked that. Stop overthinking it.

+1

 

[seahorse]

+2

 

[botus]

check out the other guy's noisy video - and the comments there I just posted about mine - then lets pretend there's nothing to worry about ?

 

[gazza12adv]

check out the other guy's noisy video - and the comments there I just posted about mine - then lets pretend there's nothing to worry about ?

I wasn't saying there's nothing worry about . It was a comment on your trials and tribulations about how much oil to put in.
Hense me saying I use 1 litre for final drive and gearbox.