K-bike
Instrument Pod
K bike
instrument pod: Repairing & Calibrating speedometer;
clock mod. for 12 hour; ETC.
©
Copyright, 2011, R. Fleischer
KPod-8.htm
Here are two hyperlinks to illustrated articles on the K instrument pod....more pointed towards working on the odometer gears and speedometer, not recalibration, but very useful:
http://easternbeaver.com/Main/Stuff/BMW_Tech/Speedo_Repair/speedo_repair.htm
http://easternbeaver.com/Main/Stuff/BMW_Tech/Speedo_Repair/Speedo_2/speedo_2.html
Removing and replacing the pod is covered in the Factory Service
Manual, section 62.
Remove 4 each 4 mm Allen screws and their washers on the
underside of the pod assembly....do NOT let them fall into the
fairing! Remove the pod cluster and connector. Remove the
Phillips screws around the periphery, remove the rear plate. Pull
off the odometer knob, don't lose the O-ring.
Remove Phillips screws. Remove the one small black slot head
screw next to the silver metal bracket on the speedometer side of
the cluster.
The speedometer calibration is adjustable by means of a
potentiometer (term for, in this case, a small rotary electronics
rheostat), which is located on the side AWAY from the odometer
stepper coil, towards the lamps...just above the yellow plastic
gear, and if the speedo is not separated from the rest, it won't
be seen....as it is behind the gears that drive the odometer, on
the small PC...that the 3 pin connector plugs into. Rotating the
adjustment COUNTER-clockwise will make the speedometer read LESS
fast.. There is a single black screw on the back of the
speedometer that attaches it to a plastic arm, reaching from the
center carrier. Remove that screw, and the speedometer can be
moved forward to access the potentiometer. Lift away the
subassembly, exposing the adjustment screw. Reconnect, power up
the ignition, and apply magnetic field to the pickup at the rear
wheel, and adjust the potentiometer.....at right side edge of the
PC on the speedometer subassembly. If you are
adjusting the speedometer to make it read correctly with the
stock rear tire size, the procedure works easily and
well. If you are adjusting the speedometer for the
reason the Author did, because he had a K1100LT with a sidecar
attached, and a rear car tire with a much smaller diameter, then
you need some sort of data, first, as to how much change to make
to the speedometer. That can be done using a GPS, or road
mileage markers and a watch.
Information on the
magnetic pickup, the magnetic needed, etc:
There are TWO basic methods to enable
calibration:
1. If you will be happy with just one calibration
adjustment/check, then the EASIEST thing to do is to use a common
soldering gun, which produces QUITE a large magnetic field, and
turn on the bike ignition and simply put the soldering gun,
trigger depressed, NEAR the rear drive pickup (not too
close). As you bring the soldering gun, energized, towards
the rear drive, the speedometer will suddenly start to move, and
you need only to move the soldering gun JUST close enough for a
solid stable reading. Since the power line is a VERY
accurate 60 Hz (in the USA), for a stock tire size, the
speedometer should read exactly 45 mph. If you are in
a 50 Hz country, or a country with Kilometer readings, simply
make a simple conversion. There is NO easy way to calibrate
the ODOMETER. There IS an electronics 'box' available on
the market that can convert the rear signal to a signal that
works both speedometer and odometer accurately, but it is
pricey.
2. The other method is to make up some sort
of solenoid with enough turns that an audio amplifier can drive
it. Place the magnetic field near the rear drive speedometer
pickup and with the ignition ON, notice the speedometer
effect. You need a very accurate audio oscillator to drive
the audio amplifier. This method allows you to check the
accuracy at any reading of the speedometer. You can also,
very easily, calibrate the ODOMETER (easiest at 60 mph).
MPH
HZ
10
13.33
30
40.00
45
60.00
50
66.67
60
80.00
80
106.67
120
160.00
150
200.00
For the more
nerdy:
1. The electronics inside the instrument pod is factory
set (by circuit arrangement) for a divide by 64 function; for
electrical signals from the input from the rear wheel (6 tooth
pulse wheel). It is possible to determine, from tire size, the
pulses per mile:
(64)(pulses per mile) = xxx pulses per mile from the rear wheel.
times 1/3600 = pulses per second per each mile per hour.
2. One could also measure the rear wheel rolling distance.
The rotor in the rear wheel has SIX teeth...so one could
calculate the number of pulses per so many feet and inches.
See:
http://www.ibmwr.org/
Navigate your way to the article on the
speedometer calibration. I used to have a direct URL here,
but there is something wrong with their website.
I think that the nicest way is to run on the highway, use a GPS,
compare to mileage posts, and take readings at a TRUE 60 mph, and
for an INDICATED 60 mph. Watch the Odometer too (pun intended).
NOTE the circuit diagrams, and details. The 22K ohm adjustment
potentiometer is in a series circuit with a 33K ohm resistor, and
applied across pins 8 and 10 of the UAF2115 chip (UAF1025??). It
may be that modifying that resistor value will enable enough
range for the pot, if range is not good enough as is. SO
FAR, I have not had to change that resistor value, even for a 14
or 15 inch rear tire.
Clock:
The clock is normally 24 hour. It is possible to modify the
circuit so it reads in 12 hour time.
The procedure is at: http://www.ibmwr.org/
under an article with a title something like 12-hour-clock.
I used to have a direct URL here, but there is something wrong
with their website.
Revisions:
02/08/2008: add hyperlinks at top of page
04/26/2010: ibmr.org links NLW, so used generic homepage
link and added notes.
©
Copyright, 2011, R. Fleischer
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