Gearbox problems

[cmacc]

Hello GSer's
Going home from work last Friday, 6th gear 80mph, open road, BANG!!! gearbox jumps out of 6th into a false neutral!!!

The bike, '02 Adventure, 7000 Miles, Just serviced.

Questions:
1) I have read that the GS can have gearbox problems, I take it then that its a design flaw? Therefore why haven't BMW recalled these bikes?
2) If it isn't a flaw, will replacing the gearbox (again under warranty) allow me to trust the bike in the middle of a bend, or overtaking a truck without the thought running through my head "I hope it f*@*ing stays in gear", or are the chances of it jumping out of gear just the same?

Please advise before I place an add in the bikemart!

Regards:
Conor

 

[the celt]

Conor,
Have you talked to your dealer?
I'd be well pi$$ed off, if it was mine.
regards
jose

 

[MikeO]

Conor,

Is this a regular occurence, or did it just happen the once? I've not had this problem (although I've seen it reported on the BB).

There is definitely a longer 'throw' of the lever from 5th to 6th on the 1150 gearbox, a bit like changing from 1st to 2nd. Although oilhead gearboxes are vastly superior to the airhead gearboxes I was brought up with, they need to be used correctly. That means no clutchless changes and pre-loading the lever followed by a positive action in order to ensure the gear is engaged - completely different from most japanese gearboxes.

Mike

 

[tonys]

My 8 week old has done the same sort of thing, more often dropping into 5th rather than a false neutral. I found the fix was to adjust the gearlever down slightly, so you get a more positive engagement. BTW mine will clutchless change up through the gears no problems, never drops out then, cos I'm concentrating harder on the shift, dropouts usually happened when in 'bimbling' mode, when I'd been a bit sloppy with the shift.

 

[cmacc]

Just once

Thanks for the input

the problem has just happened once, maybe it is just as simple as not engaging the gear sufficiently. I'll adjust the lever a little and see what happens. Buy the way I didn't know that the gear boxes are different than the Jap bikes, is there a place to read up about the oilhead gearbox? And I never heard about "Preloading" the lever.

Thanks for the help

Conor

 

[Mick Fagan]

Having seen the innards of Kawasaki 1200 gearbox I was extremely surprised to find that it was, in it's basic function, near enough identical to the BMW ones on the current 1100/1150 bikes.

It made me think as to why the Japanese bikes had such easy changing, compared to the BMW boxes. Basically it comes down to the fact that the input shaft on the BMW is travelling at crankshaft speed, whilst the Japanese input shaft is travelling at half that speed. That really is the major difference as far as gear shifting is concerned. This makes meshing of the gears so much easier.

Having a wet multiplate clutch that has an easy slip situation compared to the dry single plate that has a bight like a bulldog, also helps.

From a lot of experience, I know that clutchless changes on the 259 series BMW's will eventually induce damage to the selector fork(s). This usually results in gears dropping out into false neutrals.

Actually, clutchless changes on any BMW gearbox will induce damage eventually, especially pre- 1973 4 speed boxes.

Racing bikes aren't that special and the riders who do a lot of clutchless changes, sometimes have to run the last part of a race using the clutch in the hope that the box will last the distance. In the seventies when I was racing, it was reasonably normal for riders to compress a tennis ball on and off every day with the left hand, to simulate the amount of clutch changes one would do in a racing weekend.

Troy Bayliss once said in an interview, that having to use the clutch so that the gearbox would last the race distance, was something he was having to come to grips with since the new Ducati he was racing, had a dry clutch.

Mick.

 

[MikeO]

Conor,

'pre-loading' means putting some weight on the gear lever (up or down) just prior to easing the clutch in. The technique (which is taught in Police Driving Schools, where I learned it) allows the clutch to be disengaged for the minimum time, thereby ensuring the bike is under drive for the maximum amount of time and ensures a clean gear selection. As I mentioned earlier, the old airhead gearboxes were/are a lot more agricultural than the oilhead ones. Most of the time you can probably get away with clutchless upchanges with an oilhead - but I want to ensure correct gear selection all of the time.

If you've only experienced this once, I'd be tempted to think it was caused by poor gear selection. Talking about selling the bike because of it is a bit OTT, isn't it?

Mike

 

[Sergeant Pluck]

the thing about this clutchless change thing is; i do it quite a lot from 2 to 5th, if i'm cracking on.... i'm certainly no mechanic but on the way up between these gears it feels very smooth doing it, no resistance, if you get the engine speed right its really easy and fun to do. so my question is, if there's no resistance and everything feels so smooth and cushty - how is mechanical damage being done?

pr0ne

 

[Mick Fagan]

Prone, it's rather simple.

One day you'll make a mistake and it only takes one stuffed shift to damage a selector fork.

One of my good friends on his 96 1100GS, who quite often used clutchless changes on the way up, did just that on a ride.

The ride home was plagued with the box dropping out of 4th gear. The next week we pulled it out and he had a damaged layshaft gear, two damaged gears on the output shaft and two bent selector forks.

The total damage, due to the high cost of the complete layshaft, which cannot be bought in pieces, only as a whole. was $2,300 Australian Dollars.

As the bike had 120,000 Klm's on the clock and a brand new box was $3,200 he opted for the new gearbox.

His wife still tells him as he's leaving for a ride, "use the clutch, Honey". It drives him mad!

Mick.

 

[BlackBetty]

I have found on my 02 ADV this will happen between 5th and sixth if:

- the change isn't positive.
- my boot was left under the gear selector changing from 4th to 5th, disabling it from coming completely down. Changing to 6 will then put it into false neutral.

Solution

Ride the bike the way it was meant to be ridden. No problem

 

[Sergeant Pluck]

ok - so maybe i'd best leave the clutchless changes alone then!! i'm surprsied the bits are so weak, i was guessing that you'd just hear as nasty 'gear grating' noise if you got it wrong rather than buggered up internals...

pr0ne

 

[Patch]

Bringing an old thread back to life I would like to know if any other bikes are experiencing this.

Basicall my bike has jumped into a false neutral 3 times now.

1st - last week riding in traffic, in 4th gear as moving slowly and the bike went into "neutral" as I started to increase the gas, Rectified by pressing down on the gear lever which put it back into 4th so it had slipped up somehow. Revs at the time were about half way (3500)

2nd - this evening again in 4th and pretty well the same as before

3rd - this evening this time in 6th but again about mid way through the revs, the bike slipped into "neutral" and I had to change up to 6th again so it had slipped down.


I will be taking the bike to SPC tomorrow to request they deal with it (04 Adv 7500 miles)

I have fitted auxillary lights, fitted in accordance to the instructions here, but can not see how this could have affected the gearbox in any way.

So is this a unique occurrence or is there a common theme?