Under the right side of the tank
you will find a white "additional instruments" connector:
It has four wires:
Switched 12V+(from Fuse
For the temp gauge you will need
to replace the drain plug on the bottom of the water pump
with a temp sensor (BMW part 62161459270) and a temp sensor
lead (BMW part 61121459511). The copper crush washer for the
temp sensor is part 07119963072.
Caution: Do not use he-man torque when installing the
temp sensor in the water pump or it will tear apart. The
correct torque is 9 Nm or 80 in-lbs.
The temp sensor lead should
follow the same path as the lead from the oil pressure
switch. The input to the temp gauge from that lead is a
The short intermediate wiring
harness for RS and K1 models is part 61121459488. For
RT and LT models you need two intermediate wiring harnesses
- 61111459767 and 61121459768. These are rather expensive
though so you may want to consider wiring up the gauges
For RS models, the gauges mount
in the left and right front panels in the fairing - parts
46631453937 (left) and 46631453938 (right).
For RT and LT models with a fixed
windscreen, there is a plastic panel (46632303616) and metal
underplate (46632303615) that replace the crossbar member.
Other options are to mount them
where the speakers would go or there are also some handlebar
gauge mounts for RT/LT bikes:
If you're careful with hole
placement then gauges can be installed in the sides of the
Given how the fuel level senders
work on 1985 and earlier K100s, it is not possible to hook
up a fuel gauge. You can only add a temp gauge by adding the
temp sensor and lead described above. There is no
additional instruments connector in the wiring harness so
you need to tap into green/black, gray/blue and ground wires
in order to power the temp gauge.
© 2013 Drake Smith - Please do
not use or reproduce this elsewhere. Feel free to link
to it though.