Author Topic: Speedometer Calibration  (Read 24947 times)

Offline frankenduck

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Speedometer Calibration
« on: June 08, 2011, 11:26:21 AM »
K Bike Speedometer Calibration

K bike speedometers usually run about 10% from the factory and it's just plain annoying - at least to me.  Based on the IBMWR tech pages, I have my speedometers recalibrated so that they are just a wee bit fast.  That way, in a 60 mph zone, when the speedometer is running at indicated 70mph I'm actually doing 68-69 mph and not breaching the 10 mph over common speeding ticket threshold.  With a GPS, it's fairly simple to recalibrate your speedometer.

Tools required:

3mm and 5mm Allen wrenches

Phillips screwdriver

Small flat jewelers screwdriver

Handheld or other GPS device

Soldering iron

Here's how to do it:

Get a recalibration reading: Remove the speedometer sensor from the final drive. Turn the bike on. (It doesn't have to be running.) Hold the soldering iron near the speedometer sensor.  The speedometer should now read at about 45mph or so - the speed associated with the 60 Hz magnetic field generated by the soldering iron. (US and Canada electrical systems are 60Hz.)

Go for a ride: Taking a handheld or other GPS device with you, go for a ride.  Get the bike going a constant indicated 45mph (or whatever your recalibration speed was) and look at the speed on the GPS. (Usually about 41mph.)  That is what your real speed is when the speedometer sensor is at 60Hz.

Remove the instrument cluster: Remove the four 5mm Allen bolts on the back of the instrument cluster that hold the instrument cluster in it's bracket. (You'll need to remove one of the side panels for a K75S - a major PITA.) Then, depending on the year, there is either a Phillips screw or 3mm Allen bolt that holds the wiring harness connector to the back of the cluster.

Remove the instrument cluster back plate: Place the instrument cluster face down on a towel or something to prevent scratching it up.  Depending upon the year, there are either 7 or 9 Phillips screws around the perimeter securing the back plate.  There is no need to mess with the ones in the middle of the back plate.

Remove the "guts": There are six screws that hold the guts in the instrument cluster - four at the middle bottom and one on each side. Remove those six screws, turn the cluster over and carefully shake the guts out - pull out the trip odometer know as far as it lets you while doing this - there's a notch in the side of the speedometer face plate which lets it by the trip odometer rod.

Warning: Be very careful with the instruments once removed.  Try not to get fingerprints on the face plates and be very careful with the speedo and tach needles - they will fall off if you look at them crossways.

Loosen the speedometer from the assembly:  There is a very small black screw in the white plastic in the lower outer corner. That will loosen the speedometer assembly from the rest enough for you to gain access to the potentiometer which controls the speedometer.

Locate the small potentiometer: The arrow below shows the potentiometer that controls speedometer calibration.



Adjust the potentiometer: Usually, using a jewelers screwdriver to turn the potentiometer counterclockwise about 45 degrees will get the calibration pretty close.

Test and adjust the calibration: Remove the speedometer sensor from the final drive again.  Hook the instrument cluster back up to the bike, turn the bike on and place the soldering iron near the speedometer sensor again.  The speedometer should read close to what you found was your true speed with the GPS (e.g. 41mph).  Perform minor adjustments to the potentiometer as necessary until you are satisfied that the speedometer is calibrated to your liking.

Another Warning: If, when testing, you misalign the connector pins on the instrument cluster when hooking it up you can fry your $75 Bulb Monitor Unit in the relay box.

Reassemble:  Reassembly is simply the reverse of disassembly.  Be sure to remember to pull the trip odometer out while sliding the guts back in.
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Rick G

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Re: Speedometer Calibration
« Reply #1 on: June 08, 2011, 08:58:37 PM »
I recently downloaded a small program in German for calibrating the speedo.

It plugs from the speaker jack on the poota to the sensor wires and pulses are sent acording to which tyre you choose.

I have not tried it yet but will be in the next few days so I shall let you all know how it goes.

Being in German doesn't pose a problem as it is very self explanatory.

Offline frankenduck

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Re: Speedometer Calibration
« Reply #2 on: June 08, 2011, 09:23:37 PM »
I recently downloaded a small program in German for calibrating the speedo.

It plugs from the speaker jack on the poota to the sensor wires and pulses are sent acording to which tyre you choose.

I have not tried it yet but will be in the next few days so I shall let you all know how it goes.

Being in German doesn't pose a problem as it is very self explanatory.

I've read up on that technique and I'm sure it's equally effective.  I've found the 60 Hz from the soldering iron works well.  I usually set mine just a wee bit high.  That way if the speed limit is 60 mph then I run an indicated 70 and know that my speed is in the 68-69 range.  That works well here in the states as most LEOs won't nab you until you hit 10 over.
93 K11LT
94 K11RS- "Kato"
86-97 K75F (K75/100/1100 Frankenbrick)
86 K75C w/ paralever, high perf. cams,TURBO!
91 K1
86 custom K100
and 2 more
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Offline robleyd

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Re: Speedometer Calibration
« Reply #3 on: June 08, 2011, 09:51:46 PM »
For us in 50 Hz country, is the relationship between Hz and speedo reading linear?
Motobrick member #70
1996 K1100 LT
1969 Triumph Bonneville

Rick G

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Re: Speedometer Calibration
« Reply #4 on: June 09, 2011, 02:55:35 AM »
On my K75 50Hz makes it read 61kph. It is an effective way to set the speedo.
It has been a bit cold here today 6o so I have been wimping inside redoing many of the wiring diagrams I have into colour so I haven't had the oportunity to find if it works yet.

Offline robleyd

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Re: Speedometer Calibration
« Reply #5 on: June 09, 2011, 04:28:08 AM »
Allowing for the assorted conversions that seems very linear to me.
Motobrick member #70
1996 K1100 LT
1969 Triumph Bonneville

Offline frankenduck

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Re: Speedometer Calibration
« Reply #6 on: June 09, 2011, 05:29:28 AM »
For us in 50 Hz country, is the relationship between Hz and speedo reading linear?

Yes.
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86-97 K75F (K75/100/1100 Frankenbrick)
86 K75C w/ paralever, high perf. cams,TURBO!
91 K1
86 custom K100
and 2 more
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Rick G

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Re: Speedometer Calibration
« Reply #7 on: June 13, 2011, 06:41:34 AM »
On my K75 50Hz makes it read 61kph. It is an effective way to set the speedo.
It has been a bit cold here today 6o so I have been wimping inside redoing many of the wiring diagrams I have into colour so I haven't had the oportunity to find if it works yet.

Good news fellow Motobrickers the program I refer to works well I have just calibrated my speedo on the K1100 and it is now spot on at 100kph and about 2kph low at 140 and 1kph high at 30 & 50kph.
The 100kph reading corresponds with my GPS.
It's called Karamba I know the K100 site has it there.

Offline frankenduck

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Re: Speedometer Calibration
« Reply #8 on: June 13, 2011, 06:59:33 AM »
Here's a linky to a write-up in English: http://k100rt.aforumfree.com/t2038-karamba-speedometer-calibration-program-tutorial.

I attached a copy of the program to this post.



93 K11LT
94 K11RS- "Kato"
86-97 K75F (K75/100/1100 Frankenbrick)
86 K75C w/ paralever, high perf. cams,TURBO!
91 K1
86 custom K100
and 2 more
IBA #17739 (SS1K, BBG, 50CC)

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Offline frankenduck

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Re: Speedometer Calibration
« Reply #9 on: June 13, 2011, 07:30:35 AM »
I was wondering about doing this on the workbench using the Karamba program. All of the K bike instrument clusters have the same pinout for the speedometer.  Looks like it would be pretty easy:

Pin #Wire ColorFunction
6Green/black for 2V K bikes12V+ power
6Green for 4V K bikes12V+ power
22YellowSpeedometer sensor
23BrownGround

When I have a few minutes I think I'll give it a shot.
93 K11LT
94 K11RS- "Kato"
86-97 K75F (K75/100/1100 Frankenbrick)
86 K75C w/ paralever, high perf. cams,TURBO!
91 K1
86 custom K100
and 2 more
IBA #17739 (SS1K, BBG, 50CC)

Buy parts HERE

Rick G

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Re: Speedometer Calibration
« Reply #10 on: June 13, 2011, 07:37:24 AM »
Doing it on the bench would sure make it easy.

Offline frankenduck

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Re: Speedometer Calibration
« Reply #11 on: June 13, 2011, 02:52:59 PM »
I soldered up a bench calibrator this morning using an old instrument cluster connector.

Wired as follows:

Pin 6 (Green/black on 2V bikes, green on 4V bikes) to positive terminal of battery

Pin 22 (yellow) to one of the the non-ground terminals on a 3.5mm stereo plug

Pin 23 (brown) to the negative battery terminal and the ground of the 3.5 mm stereo plug


Works as planned on the bench when hooked up to a couple of speedos I've got laying around.

(I also tried powering it with a 9V transistor radio battery since I use those to test gear indicators but it reads low so it seems as though the speedo needs a full 12 volts.)

I need to tweak the calibration on my K1 a bit so that will be my real life test.

The odometer sure does spin when you set it to 240 kph.  8)

Edit: 7/14 to replace missing photo.
93 K11LT
94 K11RS- "Kato"
86-97 K75F (K75/100/1100 Frankenbrick)
86 K75C w/ paralever, high perf. cams,TURBO!
91 K1
86 custom K100
and 2 more
IBA #17739 (SS1K, BBG, 50CC)

Buy parts HERE

Rick G

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Re: Speedometer Calibration
« Reply #12 on: June 13, 2011, 08:07:59 PM »
Yeah i looked at the odo wizzing around and thought  I had better slow down, I don't like life going that fast.
My speedo started dancing around when I set the 240 so it may have a problem that needs checking.

Offline seantx

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Re: Speedometer Calibration
« Reply #13 on: March 12, 2012, 11:26:41 PM »
Resurrecting an old thread. 

So the karamba program makes the calibration corrections programmatically? No need to adjust the pot with a screwdriver?

Offline frankenduck

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Re: Speedometer Calibration
« Reply #14 on: March 12, 2012, 11:30:40 PM »
Resurrecting an old thread. 

So the karamba program makes the calibration corrections programmatically? No need to adjust the pot with a screwdriver?

No, it just emulates the input signal.  You'll still need to adjust the pot.

Side note:  You'll need a sound card with some decent power output (or maybe some kind of amp) for it to work properly.  I've since tried Karamba with both a netbook and a laptop and neither of them had a strong enough signal to work properly. My desktop had just enough output. I've gone back to the soldering iron method....
93 K11LT
94 K11RS- "Kato"
86-97 K75F (K75/100/1100 Frankenbrick)
86 K75C w/ paralever, high perf. cams,TURBO!
91 K1
86 custom K100
and 2 more
IBA #17739 (SS1K, BBG, 50CC)

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Offline rbm

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Re: Speedometer Calibration
« Reply #15 on: March 13, 2012, 11:50:33 PM »
Are you certain that the master volume control on either the laptop or the netbook were set to the maximum?  The signal required by the speedo is easily achievable with the sound hardware on a laptop. No additional power from the card is required because it is not power which activates the speedo, it is signal amplitude.  So, the maximum signal must be output by the computer by adjusting the software controls properly. 

I use an ASUS EePC running Windows 7 Home when testing with Karamba.  I have also successfully tested the speedo using a Dell Latitude and Macbook Pro running VMWare. I make sure that the sound control in the task bar is set to maximum as is the master control in the Sound properties in Control Panel.
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Offline frankenduck

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Re: Speedometer Calibration
« Reply #16 on: March 14, 2012, 08:14:29 AM »
Yes, I think I can figure out how to adjust the volume on a PC. :easy:
93 K11LT
94 K11RS- "Kato"
86-97 K75F (K75/100/1100 Frankenbrick)
86 K75C w/ paralever, high perf. cams,TURBO!
91 K1
86 custom K100
and 2 more
IBA #17739 (SS1K, BBG, 50CC)

Buy parts HERE

Offline DRxBMW

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Re: Speedometer Calibration
« Reply #17 on: March 14, 2012, 08:41:16 AM »
Yes, I think I can figure out how to adjust the volume on a PC. :easy:

Thanks for the info on the speedo cal Duck.  Somehow, I missed out on that thread all together.

Local K 100 rider has a speedo that is way under.

My German skills are severely lacking, NICE to have the program in English.
Gary
Williamsport,Pa

1994 K 75 ABS "custom"
2005 F 650 GS

Offline seantx

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Re: Speedometer Calibration
« Reply #18 on: March 25, 2012, 04:35:33 PM »
Got the speedo calibrated last night thanks to this post. Thanks Duck.

I don't really see the point of the software. Yes, it will allow you to see what speed the speedo should read. You still have to remove the housing and disassemble to make any adjustments (the "hard" part). A GPS and a ride (the "easy" part) will do the same thing as the software. The soldering iron method is dead on at 45mph/60 Hz. Maybe I'm missing something.  :dunno

Offline wmax351

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Re: Speedometer Calibration
« Reply #19 on: April 05, 2012, 03:21:03 PM »
The program allows you to generate the signal while the cluster is off the bike. You can supply 12v power to the cluster, and adjust the speedo while using the signal. The other methods require taking the cluster off multiple times, or to work with it on the bike, with the pickup attached to the harness still.
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Bikes:
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Offline F14CRAZY

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Re: Speedometer Calibration
« Reply #20 on: July 06, 2014, 05:22:26 PM »
I'd suggest pulling on the trip odometer knob only as much as needed...the tiny snap ring can come off resulting in the spring, washer, and snap ring exploding across your living room with little chance of being found again
  • Grand Rapids, MI
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Offline The Mighty Gryphon

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Re: Speedometer Calibration
« Reply #21 on: August 19, 2014, 01:08:38 PM »
Bought a spool of 26awg magnet wire and put about 250 wraps on a 3/8" x 4" bolt I had laying around.  Did the 45mph at 60hz calibration using an old doorbell transformer.  Set it to read 47 to put in a 2-3mph safety margin at 70mph.  Piece of cake; took about 5 minutes once I got the speedo opened up.
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Offline johnny

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Re: Speedometer Calibration
« Reply #22 on: December 31, 2014, 09:15:24 PM »
the karamba method from k100.com... i tried it... i was too high... butts if you do it sober it works... so i hear...

j o
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Offline franck

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Re: Speedometer Calibration
« Reply #23 on: January 22, 2016, 07:30:32 AM »
Thanks for some really helpful info.  I am renovating a British registered K75C (1986) and I have canibalised two speedos to end up with one in kph to comply with French requirements.  The first bench test went well and I recalibrated the speedo with the Karamba software without problems.  On a trial run the speedo got as far as 40 kph and no further.  I have the speedo back on the bench and testing it using the Karamba software and all  works fine up to 100 kph, after that the needle falls back to about 80 and wanders about.   
Could this be a case of bad contact?  I cleaned the pins but no improvement.  Any ideas?


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Offline ithacalarry

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Re: Speedometer Calibration
« Reply #24 on: May 02, 2017, 12:20:36 PM »
Thank you for the speedometer calibration information! I used the local school zone where the speed limit is 35 MPH and there is a radar sign showing you your speed. Also used the soldering iron (Didn't pull off the sensor. Just left it bolted in place.) Truly ingenious. I've been riding Beemers for years and have always lived with the overly optimistic speedometers. Not any more. Thank you so much for the information!
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