'Sticky' or slow neutral light

[Nick591]

1999 1100GS with 47K miles. This has only started happening recently. Sometimes when first turning on the ignition when the engine is cold and sometimes while riding, when neutral is selected the neutral light does not come on immediately but there is a few seconds delay. I am not familiar with the mode of operation of the switch itself but does this sound like a mechanical switch problem or an electrical problem? The gear indicator on the RID works fine and 'in real time'.
If switch replacement is needed is it a big job?
Thanks for any input.

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[Ian J Hartley]

Mechanical switch problem. Probably just needs cleaning with brake cleaner or WD40.

The Neutral light switch and gear selector switch on your bike are separate switches located on the back of the gearbox. Just follow the wiring loom to locate them.

 

[Nick591]

Thanks Ian, that is reassuring. I will check it out.

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[Cook1e]

I had a similar problem with an RS several years ago. It's possible (but a bitch of a job) to remove, dismantle, clean and reassemble the switch.

 

[ThreeDawg]

If you do need to get at the switch on an 1100 you will need to take off the swinging arm. You'll need plenty of heat on the pivots to loosen the Loctite if it hasn't been done before.

Remove the bevel box first as it weighs a ton, (might be possible to skip this, but it is heavy) and don't forget to phase the shaft joints correctly when reassembling.

 

[Cook1e]

If you do need to get at the switch on an 1100 you will need to take off the swinging arm.

I may well be mis-remembering, as it was more than 5 years ago and I'm at an age where I'm prone to that, but I think I used gynecological techniques. I'd had the gearbox out and rebuilt it, and the problem showed up on the test-ride. Of course the RS and the GS may be different.

 

[ThreeDawg]

I think even if you can do it with the arm in situ it might be risky - you need to watch that you don't damage those small screws and maybe they'd benefit from a gentle tap if they've been in there 23 years.

Personally I'd wait until there was a better reason to remove the swinging arm like doing the clutch, and replace/clean the switch then. As long as the switch on the clutch works you'll be able to get the bike started.

 

[Nick591]

Good points all, thanks. I'll try the non-dismantling methods to start with.

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[ThreeDawg]

IIRC the neutral switch is underneath the gear indicator switch (they're piggybacked) so there's nothing much you can do without taking the whole lot apart. A job for the winter eh?

 

[Rich C]

A well timed thread.... Mines exactly the same... been like that for 18 months or so...

Are we saying here, for the non technically able folk such as myself , that the non disassembly method is to spray liberal quantities of wd40 or similar in the general area of the switch?

cheers

 

[B4bertie]

Mine is also the same.... I tried spraying WD40 but it made no difference. It does seem to be more responsive when I've been riding for a while. I traced the wiring to a connector above the left side footrest and also sprayed some WD40 on each part (although the connections looked ok). Not ridden since but not sure it'll make any difference.
I've kind of given up and just look at the gear position indicator to see it's in neutral and gently let the clutch out just in case

 

[MasaTku]

One well-known problem of BMW is this "lazy" neutral light, which is often explained as a microswitch problem.
I think this theory is incorrect, making the problem more of an internal problem in the transmission, targeting the centering of the derailleur drum.
The easiest way to reduce the problem is to change the gearbox oils to factory recommendations.

see structure of the gearbox, figure 5

Installing Selector Forks; Installing Selector Drum - BMW R 1100 RT Repair Manual [Page 230]

BMW R 1100 RT Manual Online: installing selector forks, Installing Selector Drum. L Note: Fit Rollers (1) On Guide Pins And Apply Some Grease To The Pins. • Install Selector Fork (2) For 5Th Gear In Underside Of Output Shaft With Short End Of Guide Facing Up- Wards. • Install Selector...

www.manualslib.com

 

[The Other PaulG]

If either of you do dismantle things and find you have a defective switch, please let me know.

Steptoe gave me one a while ago - gratis - which I never ultimately needed because the original switch did a Lazarus and started to work perfectly.

Steppers was kind enough not to charge me for it... I'm prepared to let it go for the same price!

 

[ThreeDawg]

One well-known problem of BMW is this "lazy" neutral light, which is often explained as a microswitch problem.
I think this theory is incorrect, making the problem more of an internal problem in the transmission, targeting the centering of the derailleur drum.
The easiest way to reduce the problem is to change the gearbox oils to factory recommendations.

see structure of the gearbox, figure 5

Installing Selector Forks; Installing Selector Drum - BMW R 1100 RT Repair Manual [Page 230]

BMW R 1100 RT Manual Online: installing selector forks, Installing Selector Drum. L Note: Fit Rollers (1) On Guide Pins And Apply Some Grease To The Pins. • Install Selector Fork (2) For 5Th Gear In Underside Of Output Shaft With Short End Of Guide Facing Up- Wards. • Install Selector...

www.manualslib.com

Switch is on the back of the gearbox on the 1100GS. Outside of the case.

 

[MasaTku]

Switch is on the back of the gearbox on the 1100GS. Outside of the case.

So the facts are that it is a separate microswitch on the back of the gearbox, which is connected by a tight semi-circular hole to the shaft of the gear drum.
The microswitch is controlled by a circular nylon (etc.) ring with a drop for triggering the microswitch.
This microswitch either works, or it doesn't, and only the position of the nylon ring defines the "slowness".
You can verify this by the fact that if you have the "slow neutral light" as a problem, immediately shift the gear to e.g. first gear, and then to neutral, and the neutral light will probably come on again. Or, alternatively, when idle, move the motorcycle either forwards or backwards, and then the movement of the gears will cause the light to come on.

If there is more interest in the matter, you can also familiarize yourself with the content of my FB, where I discuss this BMW gearbox problem in a circle of friends ;-)

https://www.facebook.com/MasaTku/posts/pfbid02LpCrJZaFEQWTpTdTxPhzXky7rov7toJhHRLLV5TXRGtk9g4smUQKUhBjkoX19RtLl

 

[MasaTku]

Now, guessing in hindsight, I'm guessing that a big part of the reason why Bemar's gearbox has broken even now in 2021 without even touching the motorcycle in the winter is this shifter shaft bushing, which was partially stuck to this original slide bearing.
Before the assembly, I modified that sliding bearing to improve lubrication, and now this repaired gearbox has worked with these fins for about 30,000 km/2.5 years, and maybe even better than it has ever worked before.