The ads above are Google-sponsored.
Clicking on them at every visit helps support this website!
Clicking on something inside an advertisement helps even more!!


Classic K-bike: 
Instrument Pod. Radio.  Repairing & Calibrating
the Speedometer.  Clock Modification for
12 hour reading.  Resetting Radio Code.

Copyright, 2012, R. Fleischer

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:

There are articles on the instrument pod for the K bikes here:

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 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.

Speedometer calibration:   Adjustable by means of a potentiometer, a term for a rotary electronic rheostat, in this instance a quite small one.  It is located on the side AWAY from the odometer stepper coil, towards the lamps...just above the yellow plastic gear, and if the speedometer unit is not separated from the rest, it won't be seen.  It is behind the gears that drive the odometer, on the small PC...that the 3 pin connector plugs into.   You can see it in a photo, here (or, someplace in the article or links??):
IMO, the Karamba calibration program, etc., is too complicated, and there are easier methods for the average person, and I have them, below.

Rotating the adjustment COUNTER-clockwise will make the speedometer read slower. 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 right side edge of the PC on the speedometer subassembly.  The above link has information on making up a cable/connector and using a computer program to adjust the reading, but I expect very few of you will do that, and the information in the article below will work quite well, and without the need for a laptop computer, modifications, software program, etc.

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 read the linked article, above, you will see that modest changes in the rear tire size don't affect the speedometer all that much.  NOTE ALSO THAT YOU CAN TRAVEL DOWN A STRAIGHT ROAD USING A GPS, AND READ THE SPEEDOMETER, AND IF YOU NOTE THE ERROR, YOU CAN ADJUST THE POTENTIOMETER WITH THE POD CONNECTED TO THE MOTORCYCLE, TO COMPENSATE.  THIS REALLY DOES WORK 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 is where a GPS shines....or, just use road mileage markers and a watch.

Information on the magnetic pickup, the magnetic field needed, how to produce it, etc:

1.  Use a common soldering gun, of the type that has a transformer, which produces a large magnetic field.  Turn on the motorcycle ignition.  Bring the soldering gun body, trigger depressed, near the rear drive pickup (not too close).  As you bring the soldering gun, energized, towards the rear drive, the speedometer needle will suddenly start to move, and you need only to move the soldering gun 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.  NOTE that while this should be close to perfect, it might not be.  Recheck using a GPS.  Re-adjust for perfection, if you want to.  How to do this might be to travel at 45 mph indicated on the GPS, and note the error on the speedometer.   Back at your garage, use a magnetic field source, and adjust the potentiometer to correct the error. You can do it the other way too, ride at an indicated, on speedometer, of 45 mph, then read the GPS, then adjust/compensate.

If you are in a 50 Hz country, or a country with Kilometer readings, simply make a simple ratio conversion, and convert to Kph if needed for your speedometer (many speedometers have dials calibrated in both, so no calculation may be needed). 

There is NO easy way to adjust the ODOMETER.  There is NO adjustment in the instrument pod.  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. Only those who have made a MAJOR change in tire diameter, should even consider such a method; after all, the speedometer can be adjusted as shown in this article, and the odometer will simply read too fast, if a smaller tire is installed.    To give you an idea, when I changed to a 165/70 rear tire on the K1100LT, I had no problems adjusting for an accurate speedometer, but the odometer read ~12% fast.
If you do not have a magnetic field type of soldering iron, you can fashion some sort of magnetic field device from a modified bell-ringing transformer, or just use a super-strong old-fashioned magnetic tape eraser (See my SALE page); or, other means.   OFTEN a small 120 volt transformer used normally to power such as a high intensity lamp, etc., will work fine, with a lamp in it, or, just shorting the secondary.  Try it near the rear drive sensor point, ignition ON.  If it does not make the speedometer needle move, with a shorted secondary, then, if not needed for anything else, try removing the laminations such that the laminations end up being a U or T configuration, and not completely surrounding the coil. Since the magnetic field producing device need only be turned on for a few seconds at a time, you have a wide leeway in what type of devices to use; since even higher power devices need only be on a short time, and overheating would not a problem. 

Using the 60 or 50 Hz line powered magnetic field method of getting an indication on the speedometer, together with a GPS, will give you a relatively easy way to calibrate the speedometer for ANY tire size. If you do NOT use the magnetic field method, then you likely would be using the GPS method.  The only problem with THAT method is that it likely will take several 'tries'; each time making a small adjustment to the potentiometer in the pod.  However, it does work well. Road mileage marker method and a watch can be used too, of course.

2.  Another method is to make up some sort of solenoid with enough turns that an audio amplifier can drive it without injuring the amplifier. Place the magnetic field near the rear drive speedometer pickup.  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.    I suggest that unless you are very nerdy, with access to an audio oscillator and an amplifier of sufficient power, and an electronic frequency counter, that you avoid doing it this way.  NOTE, again, this is for the STOCK tire.

Checking the speedometer against a GPS on a straight road will provide checked accuracy, as it eliminates any tire effects, theoretical values effects, etc.

If you want to go so far as to make a cable up, so you can do calibration checks/adjustment, and more, for the K instrument pod, even on the workbench, and use a laptop computer, and a software program that is quite this entire article, for the more nerdy:

3.  NERDY:
  The electronics inside the instrument pod is factory set by circuit arrangement for a divide by 64 function for electrical signals from the sensor 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.  Multiply YOUR xxx value by 1/3600, and this equals pulses per second per each mile per hour.   I suggest you disregard doing things with this information.

4. NERDY:  One could also measure the rear wheel rolling distance. The rotor in the rear wheel has SIX one could calculate the number of pulses per so many feet and inches.  Go to the following site and to the Instrument Cluster section.  You will find several articles about calibrating.

5.  The best and easiest way to check and/or re-calibrate the speedometer:
Ride the motorcycle on a STRAIGHT highway.  Use a GPS.  Compare to mileage posts if you have them and wish to compare... but trust the GPS!.  Write down your speedometer readings for a GPS reading of 60 mph.   Also write down the GPS reading for the motorcycle's speedometer when IT indicates 60 mph.  Take note of the Odometer indication also, and compare against the GPS readings for distance traveled.     I suggest doing it all at both 60 mph AND 45 mph; just in case you might use a 60 Hz magnetic field near the rear drive.    All the information you need to adjust the speedometer is now available to you.    While you can make small adjustments of the calibration potentiometer, and re-test; there is a quickie way, if you have a magnetic field producing transformer, etc.    Since you will know, from road GPS readings, how much the speedometer is off in mph, you can use the magnetic field generator to produce a speedometer reading.  Whatever that reading is, simply adjust the potentiometer so the number of miles per hour of error is corrected.    Thus, the actual speedometer reading using the magnetic field method is used JUST to make a correction in MPH, but the actual READING is unimportant.   Thus, only one road test is needed to get the information, and a final road test to confirm you did things correctly!

Explaining some of this differently:
  The adjustment potentiometer is in a series circuit with a 33K ohm resistor, & applied across pins 8 and 10 of the UAF2115 chip (UAF1025??).     By comparing the reading from the soldering gun magnetic field, with the road readings from the GPS, you can figure the amount of changes you need to make to the potentiometer setting so that the soldering gun magnetic field reads what it should, for the road indications you want.  Usually the speedometer DOES likely already read 45 mph in the garage with the soldering gun magnetic field applied.   If you make it read higher, then for any true road speed, the readings will be lower.   And, vice-versa.

If you have a sidecar rig, and are using small car tires, perhaps 13 to 16 inch size, you probably will have enough range on the potentiometer to make the speedometer read correctly.  If not, you need to change the 33K ohm resistor value.  I have had no problem with 14" and 15" tire sizes and NOT changing the resistor.

Resetting the radio code:
To set the indicator ON, turn off the power and press and hold the band switch.  The numbers will disappear.  Re-enter the code.

If you made a mistake, hold the band switch again, then re-enter the proper code.

To clear the indicator, turn off the radio and press and HOLD the band switch until the light/numbers goes out.  If this does not work for you, try doing the same with the ST switch.

SOME of these radios work a bit weirdly on the code setting.

The clock is normally 24 hour. It is possible to modify the circuit so it reads in 12 hour time. The modification is simple.

02/08/2008:  add hyperlinks at top of page
04/26/2010: links NLW, so used generic homepage link and added notes.
10/08/2012:  Add QR code, add language button, update Google Ad-Sense code; simplify the article, yet add clearer and better information
                    and procedures.
04/24/2013:  Add 8; re-arrange for 9 from a separate heading.
10/04/2014:  Clean up article so is much more neatly presented, use of tabs, indentations, table.
03/13/2015:  Remove some sections, simplify some areas, expand others.
08/18/2016:  Update Clock 24>12 hour link; update metacodes, H.L., scripts, fonts, colors, layout.

Copyright, 2012, R. Fleischer

Return to Technical Articles LIST Page

Return to HomePage

Last check/edit: Thursday, August 18, 2016