View Full Version : Speedometer Jumpin Beans

04-21-2007, 05:15 AM
I am installing a NEW speedo on my custom built bike. It is a HD speedo for a 95 RK replacement. Kit number is 67017-94C and speedo p/n according to the kit should be 67017-99A but it is not. It is a 67033-95D. Speedo seems to work OK and reads correct MPH which means I must have got the wiring right.

OK..the problem....Sometimes when I turn on the ignition, the needles goes wacky, jumps all over the place and then will jump to some random MPH. I have even seen up to 100Mph where it freezes. I can turn it off and then back on and it is like rolling dice. Sometimes it works OK and resets itself to zero and sometimes not.

I went to the HD dealer and they can't help me. They are only a remove and replace type of dealer. No one there that even knows how the speedometer works. Jeez!! All they can tell me is that maybe the speedo is hunting for something and gets lost without it. What is it hunting for?

They want me to call HD customer service, which I got the ph # for and will do that, but thought I would also try here. Maybe Kagan can help...or any other expert.

Since it is a custom install, I don't have an Engine Lamp signal connected to pin 4 of the speedo. Is this a problem? Maybe the speedo on startup is looking for NO Engine problems and without it, it goes squirrely. OK, I can buy that....what shoud the signal be? Low (Gnd) or High (What value? 12v?).

The only other item not connected is the speedo signal OUTPUT on pin 12. This goes to the ignition harness on Carb'd bikes or to the ECM harness on EFI bikes. OK...if it works on a Carb'd bike without an ECM...then what is it connected to on the Carb'd harness? Is there a purpose for this output signal ....like maybe an INPUT signal when the speedo is first started up?

Grounds are OK. I double checked them....and just to boot....I installed another ground ONLY for the speedo (pin 10). This had no effect.

If no one has a clue to what the problem is....does anyone have any ideas on who I can talk to that can tell me PRECISELY what is happening and what the speedo is looking for. Or better yet, what I can do (or make) that will resolve this problem.

04-21-2007, 07:01 AM
I'll take a looky at my book tonight but not sure if I'll get the right answer
Your logic sounds on

04-22-2007, 09:53 AM
Any luck Wide in finding something?

04-23-2007, 06:23 AM
FWIW, mine jumped all over the place, similar to what you described, and I traced it down to the speedo. New speedo, no more problems. Also, the MoCo changed part numbers, so the replacement # did not match the original.

04-24-2007, 09:24 AM
Kinda what I am thinking JD. Going to bring it into the HD dealer tomorrow and let them put it on their speedo tester. Hopefully it will show up bad also and out of the kindness of their heart, they will get me a new one.......yeah, right.

05-08-2007, 10:21 AM
OK...the HD dealer could NOT help me out. Seems like all they can do is put a sensor testor connected to my speedo. That won't cut it at all. However, I have another question related to this......for our esteemed experts:

What exactly does the speedo OUTPUT signal do if you have an old 95RK without them thar fancy computers or whatever they call them? I see on some schematice that this signal FIRST goes to the turn signal module. Now what in sam hell does this signal do in that module?

Any possibility that the speedo output signal is supposed to be grounded for ~4 seconds and thereby setting the speedo needle to ZERO? Anyone know anything about this?

05-08-2007, 10:29 AM
I think the turn signal module uses the pickup (speedo) signal for the self-cancelling blinkers, all part of that module.

05-08-2007, 06:30 PM
I think the turn signal module uses the pickup (speedo) signal for the self-cancelling blinkers, all part of that module.

Yes, JD is correct when my speedo broke my turn signal would not self cancel.