This page is about the BMW motorcycle models R26, R27, R50, R60, R69, R50/2,
R60/2, R50S, R69S, R50/US, R60/US, R69US, R50/5, R60/5 and the R75/5. Some
of this info applies to earlier models also.
The headlight and ignition switches that have been used since the 30's, and
up till the end of the /5, take some care and maintenance. Used properly,
they will last for many years. Here are the things that go wrong.
Have I forgotten some? Email me to let me know.
1. The chrome cover plate gets scratched up from riders who use the key
in one hand to slide the black plastic forwards to make a space to insert the
key. Use both hands.
2. The round brass place has the hole for the key also has a slot for
turning on and off the headlight. It gets "wallowed out" from riders
"pounding" the key into place with the palm of the hand.
Never "hit" the key into place.
3. The black plastic rain cover breaks off earlier than necessary.
This is because riders use the tip of the key to push it forwards. One
should use two hands to insert the key. Pull the black plastic forwards
with one hand while the other gently inserts the key. See it below.
Insert it and gently wiggle down and into place.
4. The key goes in only with some effort, because it lacks lubrication.
Inside are two ball bearings that are held in place with a small spring that
wraps around and holds the balls in place. The balls are the detents that
drop into the grooves in the key to hold it down. If the balls and spring
lack oil, then it is hard to get into place. One must really press on it
and that causes the keyway to get wallowed out. A
drop of oil, once a year, is enough.
5. Headlight shells get badly scratched by the use of the flat metal
(emergency) key. It is often kept on a key chain and when needed, is used
while still on the key chain. The "extra" keys flop around and chip the
paint. Use the flat key all by itself.
6. The key can't quite be pushed far enough to keep the contact.
One feels the need for a longer key or a large rubber band to hold it down.
Over time one of two things can happen. The whole switch assembly can
become slightly loose and/or the contact points in front can become misaligned.
How to use the black plastic BMW motorcycle ignition key
When the key has been left in the "half in-half out" position, it is tempting
to just "bang" it into place. It will cause the keyway that
turns the headlight switch to wallow out the narrow slot that it should fit
The above photo of an old headlight shell is of the round hole that the
ignition key plugs into. The black plastic slider is broken and gone.
The bottom of the photo is the front of the shell. See the notch for the
keyway at the upper part? It is twice as wide as the one below the hole.
That is because the key has been "hammered" in and that "wallowed out" the
keyway. The upper notch, or rear one, was once identical to the front or
lower one. With this extra slop, the key may no longer turn the internal
parts far enough to make contact.
If this has happened to your switch already, as a temporary measure, you can
just turn the key backwards. For a permanent fix, one must remove and
rotate the round part so that the key will now engage the "virgin" slot that has
been facing the front.
Photo by Jeff Kuzmanoff, thanks
See the cut away arc (about 10 O'clock to 2 O'clock) where the sheet metal
has been removed? The "outer part" with the missing arc is essentially the
limit for rotating the key for the headlight and parking light switch portion of
the assembly. That must be done on the bottom side too. To do this
requires removing the entire switch plate, remove and modify the part shown and
reinstalling it 180 degrees from where it was. This isn't a nice job as
the switch plate is held in with 4 bend-over tabs of metal. With age these
tabs become brittle. These tabs will only tolerate a few bendings and then
break off. I use a short screwdriver to bend the tab. The chrome
cover also is held on with bend-over tabs. The ultimate life of the whole
assembly is determined by the tabs, which means the owner must use care.
It has been reported that one can soften the tabs by heating them up to about
red and then allowing them to cool slowly. I have never tried it, but it
One may need to replace the black plastic slider that keeps rain out of the
round hole and headlight. All work can be done while the headlight is on
the bike. It may help to remove the speedometer to get enough room to
work. The switch plate must be lowered and the chrome cover lifted.
The 4 tabs should only be bent the least amount needed to loosen the chrome
cover enough to get the broken parts out and install the new ones. I have
heard of mechanics being able to thread a wire around the post and grabbing the
spring. This would avoid the above mentioning of bending the tabs.
This would be great, but I have never done it. Let me know or put it up on
your site and tell is about it. Please.
About the headlight switch plate
This is the headlight and ignition switch plate. Look for the 4 slotted
holes that are all at a 45 degree angle and near the corners. The slots
are for the 4 bend over tabs to go into. The curved lower part has the
three detents for the light switch. On the other side of the plate are several
terminal posts that hold wires. The screws that hold them do come loose.
Once a year check them for tightness with a small slotted screwdriver.
Here is the switch plate as you would see it in the headlight shell. In
between the yellow terminals are the two horizontal brass plates. They are
the contacts for the ignition. The upper one is all the way up. This
is how it looks with the key out, which is ignition OFF.
Now you can see the contact as it would look with the key down, which is
ignition ON. It has a little tit, not seen here due to poor lighting, that
contacts the lower arm. On the /2 it need not actually contact the lower
one to allow the engine to start. Once it has moved down a tiny bit, it
has broken the contact that grounds the magneto. The red/green lights
wouldn't be on, but it will start and run. If it fails to stop when the
key is removed, then it is most likely that the entire switch plate is slightly
On the /5, the two must
actually make contact to get power to the ignition system. It will start
only when you see both (several) lights lit up. In this case you can see that the lower contact isn't quite level. It
is bent up just a tiny bit. That was probably done so that the two would
make contact. It may need to be done when one finds that the key must be
held down to get the lights to stay on. Bend this very gently and only a
bit at a time, until it is just right. The other reason that it might be
bent upwards is that the whole plate could be loose and therefore lower than
normal. If that is the case, bend the tabs up a bit more to hold it
better. I would try bending only two and only the amount needed to hold it
mounted firmly. If needed, I would bend all four of them.
If you are having trouble keeping the key operating correctly, read below
about the key.
Warning! Do not bend the actual
spring, only the arm or tabs.
Here is the plate mounted in a /5 shell, but this part is almost the same for
a /2. As time went on, 55-73, the switch plate became slightly more
complicated, with a couple of more terminals.
The various keys
Late 30's to 55 black plastic "normal" key
Late 30's to 55 flat key, for use on a key ring.
This is the black plastic "normal" key. The
first model to use this key was the R25/3. It was standard on all of the
Earles fork models 55-69 and the /5 series 1970-73. Some of the keys
offered today are not made correctly. Some are too short and don't operate
the switch properly. Some have the groove for the ball detent in the wrong
place. Make sure that your key is correctly made.
55 through 73 flat key, for use on a key ring.
BMW motorcycle theft
Do these keys all look alike? There is only one "key" and it fits all
BMW's. The 55-69 type will work in the older bikes, but they stick up too
far. All a thief needs to do, to steal a /2, is to remove the ground from
the magneto. This can be accomplished, in seconds, by cutting the whole
harness. The /5 and /6 can be started by adding a jumper, a simple wire
with alligator clips. It only takes a few seconds. The fork lock can
be defeated in a few minutes. Your bike is easy to steal, so aren't you glad
that BMW's aren't "cool" and fast? Be glad for that "stodgy image."
The black plastic rain cover (slider)
The black plastic rain cover breaks and is unavailable. A repro is
available, but it is slightly different and you can see the very small
differences. These were sent to me by Lonnie to photograph for your
information, thanks so much. I do appreciate all that Lonnie and others
have done to improve this site.
The weight is slightly different; new is 2.95 grams and the old one is 4.4
grams. Both have a diameter of the pins that hold the spring to within
.001" but the new one has better quality control over it's roundness. The
old one is actually old and not shiny any longer. The new one is very
shiny. I hope that the photos show the several small differences in the
molds, of which none are important. The main difference I can tell is the
new one is far more flexible. It has been noticed that when installed it
can be pulled out forwards and then lifted up about 1/2". On the right
picture the old one shows considerable wear on the place where the plastic rubs
the key shank. The new one shows a "V" shape and it is rounded on the old
one. In normal proper use the repo is great.
The old black plastic covers are shown on the left and the new ones on the
right. The new ones are far more flexible than the original ones.
This should reduce the tendency for the ends to break off.
This is the key for opening the tool box on the top of many gas tanks from
the early 30's to the mid 70's. It has a square end, but the proper sized
slot screwdriver works just great. Many riders seldom used the key to open
and close the lid. Just push down on the cover to compress the thick
rubber gasket and hand screw the round fastener in only finger tight. Let
go of the pressure and the "lock" is quite tight. To unlock it, just
compress it again and turn it out with your fingers.