1 85 K100 Speedometer Issues Sat Sep 16, 2023 7:23 pm
Chris350
active member
Hi All,
I've spent way more hours than I care to admit on this BUT here it goes...
I have what appears to be a fully functioning instrument cluster minus the speedo and odometer. RPM, gear indication, 7L/4L gas warning, choke, battery, oil, temp, clock, neutral, turn light indications all work.
My father used to own this bike and from what I remember (this is like 25 years ago) the speedo intermittently worked then. He would tap the speedo side with varying success, sometimes the speedo would pop right back up and other times not. So my first thought was some cleaning with deoxit.
What I've tried with the instrument cluster on the bike:
1. I removed the cluster and cleaned with deoxit the following:
2. I ensured the female clips (don't know what these are called, the clips you bend inwards to ensure good connection with the male part) on the 4 pin speedo amplifier and 3 pin "arm" at the top of the unit were tight
3. I rotated the 4 male pins on the speedo amplifier board about 5 degrees (Something I read on the forums that may help with connection)
4. I rotated the 3 male pins on the "arm" at the top of the unit that connect into the horizonal circuit board about 5 degrees (Something I read on the forums that may help with connection)
5. I rotated the potentiometer slightly (maybe to help if it had a dead spot)
6. I removed the rubber covering around the 23 main connectors into the cluster, no signs of burning or loose pins
7. Ensured the speedo face plate is nice and flat, it has not delaminated causing the needle to hang up or stick
8. Ensured the speedo needle moves freely and when manually turned anti-clockwise it returns to its zero position
9. Removed the impulse speed sensor from the final drive and cleaned it
10. Disconnected the impulse speed sensor near the battery/coolant tank and cleaned both yellow and brown male/female connectors with deoxit
11. Tested the resistance of the impulse speed sensor at multiple locations:
After doing those steps, with the bike on the center stand I run the bike up through gears 1, 2, 3 with back wheel spinning pretty good and I get no speed/odometer. With the wheel spinning I've played the 3 pin and 4 pin connectors at the back, wiggling them back and forth and still nothing.
Though I don't think the impulse speedo sensor was the issue, I decided to eliminate the bike all together and got K_DIAG up and running with the appropriate 3.5mm connector and a 12V 2.5 amp power supply and the following setup:
1. Power +12 V on pin 6
2. Power ground on pin 13
3. Impulse yellow on pin 22
4. Impulse brown on pin 33
I set K_DIAG to 100km/hr and with the 3.5mm unplugged I have verified I'm getting a pulse that changes with speed setting. I plug the 3.5mm in and when I hook up to 12V I get a slight bump on the speedo and RPM arms, and by slight I mean maybe 2mm, just a bump and it returns to neutral. The odo also spins slightly, I can see the gears moving slightly and then all stops. I turn on/off the 12V and I keep getting this slight bump over and over.
I've read pretty much every speedo discussion on this forum I think and tried what I found.
What I haven't tried is testing the stepper motor or any other board components, I saw one post about a guy saying his stepper motor had died. How would I go about testing the stepper motor? Any other suggestions? I'm not quite at the 'throw it across the garage stage' but I'm getting there.
Appreciate the input. Sorry for the book. Thanks.
I've spent way more hours than I care to admit on this BUT here it goes...
I have what appears to be a fully functioning instrument cluster minus the speedo and odometer. RPM, gear indication, 7L/4L gas warning, choke, battery, oil, temp, clock, neutral, turn light indications all work.
My father used to own this bike and from what I remember (this is like 25 years ago) the speedo intermittently worked then. He would tap the speedo side with varying success, sometimes the speedo would pop right back up and other times not. So my first thought was some cleaning with deoxit.
What I've tried with the instrument cluster on the bike:
1. I removed the cluster and cleaned with deoxit the following:
- All 23 male and female main connectors into the cluster
- The 4 male and female connectors on the speedo amplifier board (long board at the bottom)
- The 3 male and female connectors on the "arm" at the top of the unit that connect into the horizonal circuit board
- The 2 male and female connectors on the horizontal circuit board
- The potentiometer under the horizontal circuit board
2. I ensured the female clips (don't know what these are called, the clips you bend inwards to ensure good connection with the male part) on the 4 pin speedo amplifier and 3 pin "arm" at the top of the unit were tight
3. I rotated the 4 male pins on the speedo amplifier board about 5 degrees (Something I read on the forums that may help with connection)
4. I rotated the 3 male pins on the "arm" at the top of the unit that connect into the horizonal circuit board about 5 degrees (Something I read on the forums that may help with connection)
5. I rotated the potentiometer slightly (maybe to help if it had a dead spot)
6. I removed the rubber covering around the 23 main connectors into the cluster, no signs of burning or loose pins
7. Ensured the speedo face plate is nice and flat, it has not delaminated causing the needle to hang up or stick
8. Ensured the speedo needle moves freely and when manually turned anti-clockwise it returns to its zero position
9. Removed the impulse speed sensor from the final drive and cleaned it
10. Disconnected the impulse speed sensor near the battery/coolant tank and cleaned both yellow and brown male/female connectors with deoxit
11. Tested the resistance of the impulse speed sensor at multiple locations:
- at the first connection near the coolant tank: ~280 ohms
- at pins 22 and 23 on instrument cluster female side: ~280 ohms
- at pins 1 and 2 on the 4 pin speedo amplifier board (these connect to pins 22/23 main connector): ~280 ohms
- at pins 4 on the 4 pin speedo amplifier board and pin 3 on the 3 pin "arm" at the top of the unit that connect into the horizontal circuit board: ~280 ohms
After doing those steps, with the bike on the center stand I run the bike up through gears 1, 2, 3 with back wheel spinning pretty good and I get no speed/odometer. With the wheel spinning I've played the 3 pin and 4 pin connectors at the back, wiggling them back and forth and still nothing.
Though I don't think the impulse speedo sensor was the issue, I decided to eliminate the bike all together and got K_DIAG up and running with the appropriate 3.5mm connector and a 12V 2.5 amp power supply and the following setup:
1. Power +12 V on pin 6
2. Power ground on pin 13
3. Impulse yellow on pin 22
4. Impulse brown on pin 33
I set K_DIAG to 100km/hr and with the 3.5mm unplugged I have verified I'm getting a pulse that changes with speed setting. I plug the 3.5mm in and when I hook up to 12V I get a slight bump on the speedo and RPM arms, and by slight I mean maybe 2mm, just a bump and it returns to neutral. The odo also spins slightly, I can see the gears moving slightly and then all stops. I turn on/off the 12V and I keep getting this slight bump over and over.
I've read pretty much every speedo discussion on this forum I think and tried what I found.
What I haven't tried is testing the stepper motor or any other board components, I saw one post about a guy saying his stepper motor had died. How would I go about testing the stepper motor? Any other suggestions? I'm not quite at the 'throw it across the garage stage' but I'm getting there.
Appreciate the input. Sorry for the book. Thanks.