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75/5 ignition repair/ replacement

M

mstolpa

Mike
The ignition switch on my 72' 75/5 is going. The white metal has been broken for years but now I have to play around with the key to keep her running. Not an especially safe maneuver. My questions are: Is this a repair I am capable of myself (I'm kind of a little bit mechanical but electric scares me) and, if so, where can I find a switch and directions as to the job?

Any help is appreciated. She is parked until I can get this repaired. This is the European version so sometimes parts do not interchange.

Thanks

Mike S in Western Wisconsin
72 75/5, 2004 1150RT
 
Mike, you may not even need the switch board itself, just the "lock" parts [25]. MAXBMW has all the bits and pieces. The spookiest part is unbending the four metal tangs that hold the switch board into the headlight nacelle; bend to far or too fast and they'll break (not always). But it's strictly "mechanical". My /5 isn't "Euro" but it is a December '72 build so I imagine the ignition switch components are the same.

You can see them here at the 12:00 position.
2250-empty-shell.jpg


READ THIS >> http://www.w6rec.com/duane/bmw/ignkeys/index.htm

B0002032.png
61328048100_2_B.jpg
 
This same type of key setup is on the /2 bikes. The four tabs do present a problem. You should only bend them as much as necessary. Once bent they become work hardened...the worst situation is that they can break off. To remove the effects or work hardening, the tabs need to be annealed by heating them to a dull red and letting them cool. The issue is that you'll likely affect the paint, but possibly using wet rags placed appropriately, you can reduce these effects.
 
P.S. When you get to the point that you're ready to disassemble the "lock" put everything into one of those flimsy dry-cleaners bags. You'll still be able to see what you're working on and when the spring clips are removed the dry-cleaner bag will capture those two little ball bearings.

I was repainting my bike when I did this so heating the tangs wasn't an issue... I still can't believe actual German engineers used this construction detail. :scratch :banghead
 
OK- now I've lost the 2 little ball bearings.

Anyone know what size they are and where they go back into the assembly? Could I get replacements at the hardware store?

They are not shown in my parts manual.
 
You might be able to find a suitable BB. They aren't critical really, they just ride on the notches in the "key". Take your switch parts with you when you go.

They won't be in the parts manual because they are part of an "assembly".

You did use the dry cleaner bag trick, right?
 
Well, this bites...

My starter switch finally bit the dust; the turn signal function still works but the two little contacts, for the push button starter portion of the switch, are worn down to the point that they no longer contact the copper plunger.

Aside from the $169 price tag, there is a manufacturer back order with no ETA on replacements. In the 46 years I've owned my /5 this is the first time BMW has let me down.

And the kicker has never worked well on this bike. .. .. :banghead
 
lmo1131 said:
Well, this bites...

My starter switch finally bit the dust; the turn signal function still works but the two little contacts, for the push button starter portion of the switch, are worn down to the point that they no longer contact the copper plunger.
:banghead
Click to expand...

If you’re willing to to take the switch apart, you can increase the footprint of those contacts by carefully using electrical solder to build them up by applying solder on top of the contact. I had a similar issue with the high-low switch on the left switch pod on my 1974 /6. Been several years and it is still working.
 
If first time disassembling that switch, do it inside a large clear plastic bag for when it goes SPLOING!. Don't ask me how I know....
 
ebeeby

If first time disassembling that switch, do it inside a large clear plastic bag for when it goes SPLOING!. Don't ask me how I know....
Click to expand...

Nope, not my first rodeo.

lmo1131
P.S. When you get to the point that you're ready to disassemble the "lock" put everything into one of those flimsy dry-cleaners bags. You'll still be able to see what you're working on and when the spring clips are removed the dry-cleaner bag will capture those two little ball bearings.
Click to expand...


If you’re willing to to take the switch apart, you can increase the footprint of those contacts by carefully using electrical solder to build them up by applying solder on top of the contact.
Click to expand...

Had it apart this afternoon. Not much left to work with, but given the situation with parts unavailability, it looks like I'll be diving back in tomorrow. The upside... at least it was designed to be disassembled and serviced. Too much heat required for silver solder so it looks like soft solder will have to do.
 
Sometimes you get chicken, sometimes you get feathers.. . . :(

I attempted to add material to the ends of the contacts, but no luck. The switch is toast... . pun intended.

On a Brighter Note: I just got off of the phone with Benchmark Works; they're in the process of having reproduction switches made "off shore". Prototypes have been submitted by the manufacturer for evaluation, and if all goes well new switches should be available be end of this summer. I'm generally not a fan of re-pop parts but given the OEM situation, and reputation of Bench Mark Works I'm good with the quality that I'm sure will be there.

I'm just wondering how the parts inventory for our old bikes is holding up. I've never not been able to get any part I needed for my /5.
 
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