A crap day - drivetrain advice plz

[zerocool]

70Mph and i hear crunch crunch crunch followed by gearbox jumping out of gear and clunking in-between 5th and 6th followed by clutch in rear wheel locking and me Forrest Gumping my way off the motorway and onto the hard shoulder to a complete jerky stop.

Not my best day on the GS!

At the bike will roll forward and backwards slightly, like there is something getting in the way of gearbox or paralever gearing then stops, continued rocking forward or backward leads to eventually being able to get past the point of wheel lock with some resistance. Was a pain to get onto the AA trailer to tow home as the wheel locked half way up the ramp.

Engine runs fine in neutral so issue is obviously after the clutch.

Your thoughts on where to start and identifying if this is gearbox or shaft failure?

 

[MattW]

70Mph and i hear crunch crunch crunch followed by gearbox jumping out of gear and clunking in-between 5th and 6th followed by clutch in rear wheel locking and me Forrest Gumping my way off the motorway and onto the hard shoulder to a complete jerky stop.

Not my best day on the GS!

At the bike will roll forward and backwards slightly, like there is something getting in the way of gearbox or paralever gearing then stops, continued rocking forward or backward leads to eventually being able to get past the point of wheel lock with some resistance. Was a pain to get onto the AA trailer to tow home as the wheel locked half way up the ramp.

Engine runs fine in neutral so issue is obviously after the clutch.

Your thoughts on where to start and identifying if this is gearbox or shaft failure?

Ouch - sorry to hear this
On the plus side a gearbox seizure can be pretty nasty - you stayed on the bike and made it to the side of the road which under the circumstances is a good result (I got spat off my LC when the gearbox let go back in the day...).

Some manipulation of the back wheel should give you an idea whether it's the final drive or the shaft (no obvious movement / oil leaks from the F/D?).

However, as a degree of dismantling is inevitable, I'd just start taking things apart from the back end and see what you find - removal of the FD is pretty straightforward and should enable you to eliminate FD or shaft problems fairly quickly. My gut feeling given what you describe is a bearing or gear failure (possibly a sheared dog) in the box.

Good luck.

 

[Steptoe]

.

Your thoughts on where to start and identifying if this is gearbox or shaft failure?

Start by removing the paralever pivot pins and dropping down the final drive and checking on the condition of the drive shaft.
If it falls out in bits it's the shaft, it the shaft is fine it's the gearbox - until you actually look any opinions are just guesswork.
I've had a couple of bikes where the drive shaft U/J has broken at the gearbox end and locked the rear wheel. And i've also had more than a few gearboxes lock up when a bearing has collapsed.

I've posted the pictures of both types of failure in this section.

 

[zerocool]

Thanks guys, its as I expected, suck it and seen problem.

Ill make a start on the dismantling process tonight after work and preparing myself for the bad or worse news.

If its the gearbox and its thrown a tooth is there much that can be salvaged from the duff box or is just a oversized paperweight/doorstop?

 

[zerocool]

CV joint at the top of the drive shaft had smashed itself to pieces on the side of the housing.

Tiny dent around the bearing housing on the RHS top bearing. Metal shavings in all the bearings despite bearings being near mint.

Not bad movement in the gearbox shaft so hopefully all that is ok! *

I have a source for a shaft and housing from a RT, are they all the same?

Anybody know the bearing numbers for replacement??? £23 a piece online.... Ouch!

 

[Steptoe]

When that happens it usually damages the pivot section on R/H swingarm pivot pin as well.

So check it.

 

[zerocool]

the pin had the end smashed off and there is a tiny ding on the inside of the housing at the point where the bearing seats.

Its probably still usable but im going to see if I can source a correctly priced rear end, possibly including wheel section too as I would like a spare.

 

[zerocool]

 

[zerocool]

Does anybody know the code/measurement for the bearing for the back of the swinging arm, they are well notchy and plan to get some new ones tomorrow from a local bearing shop.

 

[davegs]

bearings

Go to the local friendly (?) BMW dealer thwese things are not expensive and you'll get the correct ones.

 

[zerocool]

They are £24 each from motorworks and I'm told only around £10 each from a bearing factors

 

[zerocool]

Correction, £17 from motorworks, £20 from BMW, and I couldnt find the bearing shop, it obviously doesnt exist at the address given as I found the address fine.

Bike is in one peice again just without the pannier racks, im going to test ride tonight before completing and prepping for some touring.

 

[warmshed]

Did you get the bearing numbers for others to get theirs from local bearing factors?

 

[zerocool]

nope but I need another 2 for my other bevel box so I will when I get chance do some research. The place was closed and not at the postcode I was given when I went, at least im presuming it was closed and the whole of the industrial estate where I ended up was closed.

Cleverly BMW printed the numbers for the bearings on the backside of the bearing so you cant get them until you have bashed them out but I have them in the garage so ill find them for you.

 

[CHANGELING]

I have always had to buy BMW for this bearing as I couldn't source an alternative supply. Interested in your experience.