Gearbox big rattles

Ditchdablade

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I’ve just started to notice big takes and chunks from the gearbox which is producing clanking through the drive train.

The bike has 72k and hasn’t had a problem before. I put some oil thickener in it earlier in the year to quieten it but it’s rapidly making noises and vibrating a bit.
What’s my course of action?
Is it start the strip. Check final drive and then splines on drive shaft and then finally remove the gear box off the clutch and try looking for excessive play in that ?

I may as well change the clutch whilst I’m at it as that’s at quite a bit of lever travel.

Just wondering if there is a certain way of finding the issue or identifying usual culprits before I water my time. I’ll be doing this myself so any good pointers appreciated.
If I run it on centre stand no load it blinks really badly and bounces the rear swing arm up and down. Hence why I can feel it through the chassis when riding. Almost like it’s excessive play in gears out the drive shaft universal joints are really work and catching on rotation.

Many thanks
 
It is not a good idea to run the bike in gear on the centre stand as the UJ`s are running at an extreme angle.
You have obviously checked the final drive for play.
My first check would be the driveshaft UJ`s.
You have not said what year the bike is.
 
my bevel has always had mega slop
after the recall for the new wheel flange this took on a new level of madness - took me 5 years to work it out - I guess they stole my good drive shaft and fitted a knackered one !!!!!
I've done over 15k mile since and I can almost get half a wheel turn of slop (with it in gear on the centre stand) its not got worse but it sounds truly awful
I asked when it was in the dealership and they just said they all sound terrible don't worry about it

I think I need a bevel rebuild a new drive shaft and some swinging arm bearings as I can see slop there now - marvellous for a well looked after bike on 34k miles - oh and the clutch slips unless you do a long ride then its sorted for 5 months
 
To be honest, a couple of years ago, I changed the gearbox oil as I was doing final drive too. The oil that came out looked as new but the gear changes improved a LOT after this.. (06 bike)
This may be a start for you, and, as the expert above said, any bug issues will be obvious.


Sent from my M2007J22G using Tapatalk
 
Final drive health check,
Rock rear wheel at 3+9 o’clock any play?
Try again at 6+12,you may need an assistant to feel where/if any movement .if only at 6+12 it may be in the paralever bearings.
Remove rear wheel,caliper and abs sensor( check for metallic bits on the magnetic sensor)
Disconnect torque arm and drop fd down.drain oil into clean container.
Check for wiggle on the input pinion( a rebuilt unit has none)
Now the drive is disconnected,rotate the disc and feel for any roughness in the bearings.
If you’ve ,
No play at the wheel,
Clean oil,
No excess clearance on input pinion,
No roughness when rotating,
Start moving forward,
You can check lower u/j and rotate drive shaft see if you get any pointers.
1200 gearboxes are usually pretty good but ,that said,most of the ones I’ve rebuilt are @ 2006
 
I’ve started the tear down. Apologies for my thread spelling. Should really check it but you guys seem to have the decipher codes lol.
So far, no real play in the angle drive. The drive shaft Uj’s seem fine. No play to speak of. I lubed them regularly. Swing arm bearings seen a little shite. Gritty and you can see the patterning on the conical bearing race ,So I’ll pop into bearing place in Derby and get some replacements.
Next is oil drop and read the silver tea leaves. I may put it in gear and put the uj back on and see what play I can feel. I may as I’ve gone this far rip the back end off, tear off the gearbox and do the clutch coming this far, just a big cost but maybe necessary.
All guidance welcome 🙏
 
Oh - another thing is the angle drive still leaks but I should post another thread on that
 
As per mikeyboys post, do that first.

Any play as he describes, then you need to get it fixed!

I had play within my rear drive unit .... didnt seem like much, but it was there

after sending it to Mikeyboy , i didnt , its as simple as that
 
Update- oil dropped, is not clear but a brown tinge to it. Read a few posts on that but should it really push me to make the decision about removal, stripping and doing the clutch now with that as a directive or …

Fill it back with clean oil, run it and drop it again soon?? There’s no bearing bits but there is contamination from something. I’ve seen bits in gear to bearing chaffing and production of high wear. How simple is it to get inside that gearbox without it throwing springs and bits everywhere and having no chance of putting it back together? I’m an engineer and I for most things but having never done one it could be a minefield. Answers and education please.
 
I had a death rattle at idle from my gearbox when on the sidestand. Stripped it down to find the input shaft has a torque damper which had split around its casing, only about 25% keeping it together. A new input shaft was about £350 plus new bearings and seals, I also fitted a new clutch friction plate in case the noise was due to slight input spline wear. Rebuilt and running smoothly again. I would post some pictures but I don't have a free photo hosting app anymore. Any half decent engineer can strip and rebuild these with a Haynes manual or REPROM, they are a piece of piss but I do have a very well equipped workshop where I work in Marine Engineering.

There is some gear noise in neutral when hot at idle due to designed endfloat and tolerances, but no worse than all the other GS's I ride in a group with.

As said already don't run the bike in gear on the centre stand with the gear train unloaded, the inertia of the rear wheel will hammer like mad.
 
Final drive health check,

No excess clearance on input pinion,
No play at the wheel,

what do we mean here...

rotational slop of more than x degrees on the input shaft of the bevel, and y on the wheel when in gear ? if so what is x and y ?

or on the last point are we talking about wheel bearing slop ?
 
So far
Stripped down the clutch. I’ve measured it and the manuals says 4.3-4.6mm serviceable. I’m measuring 5.15. But what does a new clutch come with?? The lever travel seems quite high? There is a centre plate , the push plate in the centre of the clutch on the flywheel. It seems to be bowed in the middle. Would that count for the clutch riding too high? The clutch doesn’t slip. Also would a work push rod add to this??

I may just clean up the clutch and refit if it’s 5.15mm . The rivet heads are about 0.5-1mm below the friction plate so that would indicate when it reaches 4.3-4.6 then we are into wearing rivers away and damaging clutch plates.

If a a new clutch comes with 7mm like then I’ll get one.

Advice appreciated.
 
Also the Input and output drives in the gearbox feel very smooth. Is it worth separating the cases now I’ve come this far and looking inside?? Or is it about to explode on me in thousands of little springs and stuff that I’ll never get back in line???
 
New clutch plate comes with 6.5mm The most worn plate I have seen was 3.6mm on an RT but it was slipping very badly and I had to replace the complete clutch assembly.
.
 
Fit a new clutch friction plate. A new friction plate, depending on genuine or pattern measures from 6.50 up to 6.80 .
 
Thanks guys much appreciated. I’m getting one in order. Bike in pieces.
Things to change
Clutch plate
Push rod
Felt
Bolts x 6
I need a spring clip, circle that goes on the end of the output shaft of the gearbox for the drive shaft. Going to check out motor works bmw see if they have it along with the rest on order.
 
An update

Clutch changed. Gearbox back on with no real lumpy or bearing feeling noises checks carried out before refitment.

I’m going to request a new clutch master cylinder seal to make sure that doesn’t leak as it looked a little worn. Don’t fancy wrecking a new clutch with fluid on leaking.

I’m now on rebuilding with new frame back from the powder coaters. Looks amazing. I’m going to ask a new thread on removal of the crank pulley as it’s causing me removal issues.

Thanks all of the supporters for helping me with this
 


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