BMW K bikes (Bricks)

You are not connected. Please login or register

View previous topic View next topic Go down  Message [Page 1 of 1]


active member
active member
I put my bike away late last October and took the battery out in late February to charge and apparently I waited too long. I charged up my battery with a trickle charger and alas no Cold Cranking Amperage. So, I have purchased an appropriate replacement battery and still nothing. I turn on the ignition and nothing no lights on the dash at all. The new battery has been checked and is fully charged and has loads of CCA. I have connected the positive red line to the positive side of the battery and then the remaining three lines (ground, black lead and main line) to the negative side of the battery.

Where do I look next to see what may need to be replaced?





Life time member
Life time member
It sounds like you may have a dirty ignition switch.

Been there, done that...

Present: 1991 K100RS "Moby Brick Too"
1994 K75RT "Ilsa, She Wolf of the SS"
1988 K100RS SE "Special Ed"
1994 K75S "Cheetos"
1992 K100RS "Moby Brick" R.I.P.
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175


hmm there should only be one or 2 leads off the negative  for the ground connections

it sounds like you've got at least one in the wrong place

take a pic of how you have it connected now and post it here

cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
1987 k100rs ########   "Red"  - (red sports rs TWB style )
1989 K100rt #009637   "Black Betty"  (naked rt ala Nigel , now sporting an rs main fairing )


Silver member
Silver member
Trouble shooting - Original K-100

Put a voltmeter from the engine block to the negative battery terminal.  Turn the ignition switch on.  Normal reading here would be zero volts.  If you have any voltage there your ground is bad.

Next take a reading from pin 30 of the starter relay to the engine block.  Should have nominal 12 volts there.
Next take a reading from fuse 5 to the engine block.  You should have nominal 12 volts there.
Now pin 30 of the ignition switch...You should have nominal 12 volts there.
Turn the switch on - check pin 15 from the ignition switch to the engine block.  Switch on you should have nominal 12 volts there.
Ignition switch on (Well, turn it off while you dismantle the handlebar switch) take the R/H grip apart and look for 12 volts on both terminals if the kill switch is on.  If you have voltage here something should light up.

It's just trouble shooting.  Go one step at a time and take your time.

Wiring diagram, If you don't have it it's possible to download a copy, just google it.

If the bike hasn't been properly stored (left outside for an extended period) corrosion can cause any number of electric maladies that can set in with the switch gear, connectors, anything.  It can turn into a real Easter egg hunt.

My K-100RT I bought new, it's always been stored indoors high and dry.  Never had a problem with it, well, one, the speedometer, but I digress, recently bought a K-100RS, didn't run.  Sat outside in a car port along the pacific coast, bike didn't look to bad, but the connectors, switch gear, and wiring harness was a mess.  I had to go through that one wire at a time.  Trouble was traced to the fuel injection computer, at one time someone had removed and discarded the plastic cover, moisture got in, connector corroded to the point I had to completely replace the computer module.  $400 later, a pull off with no guarantee ..but it's a grand more to go worked. Ran then.

- John

Sponsored content


View previous topic View next topic Back to top  Message [Page 1 of 1]

Permissions in this forum:
You cannot reply to topics in this forum