Neutral switch problem R65

[Eric65123]

Good day all,

Looking for some advice regarding my neutral switch.

I got all safety controls working for my bike after rewire and has been riding for a while with a new neutral switch (brass) to replace the old one since the leak was really bad and terminals were broken.

Then the other day, got issues on my neutral lamp not working. Checked all my wiring, ground, continuity and voltage on the line and all adds up.

Last check was to ground both plugs from neutral switch and it lit up, relays kicked in too which means my wiring is good.. Came to a conclusion it was the switch.

I've got an extra switch for replacement anyway so I started pulling things apart. After I removed the switch, tested the switch continuity and there's nothing wrong!! Connection open when switch is pressed and closed when not pressed.


But when screw it back in to the tranny it is open at neutral. I got the 2mm washer in there, same as before when it was working.

This may sound bad but i'm currently in denial. Is there an issue with my transmission?

Where does this switch contact inside the transmission?

This forum has helped enthusiasts like me and would like to thank you all for chipping in your experiences and expertise out.

Cheers!

[Justin B.]

Try it without the washer, and also not screwing it in all the way, maybe the switch is about to go out and something inside it is changing...

[mrclubike]

Last check was to ground both plugs from neutral switch and it lit up, relays kicked in too which means my wiring is good.. Came to a conclusion it was the switch.

 

Grounding both wires on the switch is not a valid test
What you should have done was connect them together.
If the light comes on with them together then you know for sure the switch is the problem

If it doesn't then 

Then you need to check  brown wire going to the switch
It  is a ground
Make sure that it connects to the lower left transmission mounting bolt
If that wire has broken you will get the symptoms you describe 
#25 is the neutral switch and it has a Brown ground wire going to it
 

[Eric65123]

Try it without the washer, and also not screwing it in all the way, maybe the switch is about to go out and something inside it is changing...

Thanks for your reply.
With the existing switch, tried it without the washer, connection open. (no power on starter relay, no neutral light)
With the existing switch, tried it with the washer hand tight, connection open. (no power on starter relay, no neutral light)
With the existing switch, out of the tranny, (power on starter relay, neutral light on)


With the new switch, tried it without the washer, connection open. (no power on starter relay, no neutral light)
With the new switch, tried it with the washer hand tight, connection open. (no power on starter relay, no neutral light)
With the existing switch, out of the tranny, (power on starter relay, neutral light on)

checked the dimensions of both new and old switch, everything the same. continuity checks are the same as well. not pressed is closed. pressed is open.

running out of options here guys. 

[Eric65123]

Last check was to ground both plugs from neutral switch and it lit up, relays kicked in too which means my wiring is good.. Came to a conclusion it was the switch.

 

Grounding both wires on the switch is not a valid test
What you should have done was connect them together.
If the light comes on with them together then you know for sure the switch is the problem

If it doesn't then 

Then you need to check  brown wire going to the switch
It  is a ground
Make sure that it connects to the lower left transmission mounting bolt
If that wire has broken you will get the symptoms you describe 
#25 is the neutral switch and it has a Brown ground wire going to it
 

Thanks for this. Yes, i did that too. shorted both wires and the light turns on and starter relay kicks in.. Which i reckon rules out the wiring issue.

Having two neutral switches old and new that functions the same, should rule out the switches as well.

That's why this somehow points me into the tranny as the culprit (which I would not be happy about).

Has anybody had issues on where the switch nipple contacts inside the tranny? How does this work? Any possible causes from the inside?

[Justin B.]

It's been 10 years since I had one of these torn down but here are some pics I took on the last rebuild I did that might shed some light on what goes where...

[mrclubike]

Rides on the edge of the shift cam between the arrows
Some thing with the shift mechanism would have to come loose to let the plunger ride off of the cam
But that would make the light come  on all the time
So I am at a loss 

[Eric65123]

I'll keep this thread updated until I figure it out and currently I can only work on the bike partly on the weekend since im digging holes for a retaining wall!

On centre stand right now and not running, I can shift from 1-5 and then to neutral.

At neutral, putting the new switch in, i can actually hear the spring of the plunger turning meaning its pressing itself into the disc as I screw in.

Can it be possible that shifter mechanism has come loose or the the disc might have been misaligned.

I'm still in denial that its inside the tranny.

[Eric65123]

Will there be a possibility that the gear has skipped a tooth?

[georgesgiralt]

Hello,
The mechanism is hold by two screws from the outside of the gearbox. They can be seen on the face in front of the clutch.
If the OEM switch with it's OEM washer does not operate, it could be that the selection is moving inside the tranny and going higher than BMW specified.
To be sure, install the switch without the OEM washer but with a thinner one and check it is able to switch. This way you will have checked that the switch and wiring is properly working.
If this works, you'll have to remove the tranny and check that the two M8 bolts are properly torqued. And figure why they came loose on the first place.
Has this gearbox been opened ?
Anyway, this is strange.

[Eric65123]

Thanks a lot for all your replies.

If I'd want it to work, i'd actually need to add washers to the switch.
Removing the washer just pushes the switch in more, which keeps it in contact more.

Nope the tranny hasn't been opened since.

[mrclubike]

Thanks a lot for all your replies.

If I'd want it to work, i'd actually need to add washers to the switch.
Removing the washer just pushes the switch in more, which keeps it in contact more.

Nope the tranny hasn't been opened since.

True statement
It seems it would fail closed
If the plunger comes out of alignment with the cam the neutral light would stay on not stay out  :-/
What you need to do is screw it in one turn at a time and check for continuity after each turn with it in gear
When the light goes out then stop there and put it in neutral and see if the light comes back on

[Semper Gumby]

Hi Eric,

I know you checked all the grounds, but if one specific ground is broken the neutral light will never light up.

It’s on the left hand side of the tranny.  Brown wire usually attached to the tranny bolt by the gear shift with a ring connector on the end.

Runs up the lh side of the frame behind the tranny.

[skippyc]

It does pay to rattle and tug the wires to see if there are any breaks that come on when the wire is in a certain position. 

[Tony Smith]

It does pay to rattle and tug the wires to see if there are any breaks that come on when the wire is in a certain position. 

As I understand it, the wiring checks out and so does the neutral switch.

The neutral switch was working perfectly, but now it is not.

The neutral switch is of the "normally closed" variety and is held "open" by the "wheel" in the gearbox unless it is in a specific position which allows the switch to close and turn the neutral light on.

It was working, then suddenly it wasn't.

Something has happened in the shift cassette. Sadly the only way to find out what is to open it up.