Which switch for R75/6?

[spokanetom]

I'm restoring a 1976 R75/6 and today I accidentally broke the neutral switch when cleaning the transmission. So I need to replace it. When I looked on the Max BMW parts website to see what part to get I see three different switches:

61 31 1 243 097 - SWITCH (from 09/75) $82.81
6131097 - NEUTRAL LIGHT SWITCH $29.99 (this one is brass-colored)
61 31 1 243 097N - NEUTRAL SWITCH NORIS 5 SPEED (Alternate part to #61311243097) $20.99

Mine is a 5 speed, but I don't know what a "norris" five speed is. All three of these look identical to mine below except of course for the brass-colored one. How do I determine which one I should get?

 

[20774]

I don't have access to all my info, but check this post.

Which switch??

I'm working on a '74 R90s and the transmission neutral switch is leaking through the switch itself. (oil leaking around the male electrical spades). The switch is normally closed when installed and normally open when removed. I don't know if this tranny has an updated shift kit, so I'm...

forums.bmwmoa.org

 

[spokanetom]

I don't have access to all my info, but check this post.

Which switch??

I'm working on a '74 R90s and the transmission neutral switch is leaking through the switch itself. (oil leaking around the male electrical spades). The switch is normally closed when installed and normally open when removed. I don't know if this tranny has an updated shift kit, so I'm...

forums.bmwmoa.org

Yes, I saw that post too. It mentions the same part number, but there's also one with an "N" at the end of it and they both look identical to me.

 

[20774]

Don't know what the N is all about. I'd go with the part for your year. You can put a meter across your old switch and the push the plunger. You can determine if you have an innie or outie.

IMO I would just get the pricey BMW part ending in -097 for production starting in 9/75 which is basically all '76 models. Yeah it costs a lot, but this is something you want to once and it's right. Again, do the continuity test just to confirm.

 

[olironrider]

The “N” is MAXBMW’s designation for a Noris Brand reproduction part, from Germany; a suffix to the 11 digit original BMW part number. Noris produces the ignition points now, too.
Siebenrock (also from Germany) and Noris make quality reproduction parts, often to replace no longer available OEM BMW parts and with improvements for known short-comings.
I use them with confidence.

 

[spokanetom]

Following up on the above, regarding the "innie" vs "outie" - with nothing pressing on the switch, the terminals show connected (switch is closed). When pushed in, they are not connected (switch is open). On Snowbum's site (https://bmwmotorcycletech.info/neutralswitch.htm) he says that 1976 and later uses part number 61 31 1 243 097 and this is a change from 1976 and onwards. "The reason the switch was changed is that the updated transmission shifting cam uses valleys to positively locate the switch plunger; while in the prior version the switch plunger rested on the 'mountain-tops' on the shifter cam." This fits with what I'm measuring. If the switch to indicate neutral is in the valley (no pressure on the switch) that's when it should show connectivity.

Thanks for your help! olironrider, thanks for your comment - it's good to know.

 

[20774]

IIRC the difference in the switches had to do with how/where they grounded. The earlier switches ground the circuit by the valleys/tops you describe. They had one wire going to them. When the switch fell onto a top, it create a ground and the neutral light lit up. On the later switches, with two tabs/wires, grounded by connecting the circuit between the tabs inside the switch, and the opposite wire on the switch went to ground. So when the switch was in a valley, the circuit was complete through the switch to ground, and the light would come on.

 

[AntonLargiader]

None of the 5-speed switches ground through the body; they both have two wires. The early switch is NO style and makes contact when pushed in at neutral. This made it harder to find neutral, so they redesigned the 3-4 cam and switched to a NC switch that went open when pushed in (everywhere other than neutral). By extending into a cutout at neutral, it acted as a neutral detent and helped you find neutral.