1963 Harley Davidson Servi Car speedometer

[FUUN063]

Quick question: Anyone know what the two wires go to (pos or neg, too) on the speedometer on a 1963 Harley Davidson Servi Car I'm working on for a friend. He got it and only a few wires are hooked up so I am making thing work and fixing small issues for him. I did locate and hook up the speedometer light bulb wire (works great now), but I need to know what the two wires are for that are located at about the 11 O clock position on the speedometer. They are near the small button/lever that actually mounts on the dash itself, then trips the lever on the speedometer. Any help is greatly appreciated.

As a side question, I pulled the cable and lubed it and put it back in because the speedometer, while driving, would work well up to about 30 miles an hour. Then, after this speed, the speedometer needle will wag back and forth from 30ish to about 50 or so as long as you are going faster that about 30. This bugs us both. Any suggestions are greatly appreciated as well. It should be noted that the cable looks great with no bad spots on it.

[Rubone]

That is a Speedometer hand lock. The two wires are hot on one side, and the other side goes to the handlebar button which grounds it when depressed, causing the solenoid on the side of the speedo to extend a rubber tipped shaft and stop the motion of the needle. The lever on the side and button on the base are the release mechanism.

[FUUN063]

So, that's what the other "horn switch lookin'" button is on the other side of the handle bars. One of the black wires coming from the speedometer has a crimped on eye, so I'm going to assume that it is the hot since it's only about 6" long or so (it could never reach the button). The other one looks like it has been cut and has some black electrical tape on it. I'm also going to assume that this is the one that goes to the handle bar button. I always wonder why people do some things like this and also unhooking the other wires like the speedometer light bulb wire. If only the bikes could talk. Thanks.

[FUUN063]

Well, I hooked one wire to the ground post (existing wire with the crimped eye terminal) and the other wire (cut off black wire) to the right side handle bar switch. It did not work. I then unhooked both wires. I touched the cut wire to a positive post and the solenoid clicked as it should. This then allowed the left side button on the speedometer to release the "rubber tipped plunger". I am going to guess that this feature is to record the speed that the bike is going (and presumably the "speeder" as well) by keeping the needle at the speed even when the bike is stopped. The left plunger is later depressed to return the needle to its resting spot at "0". This is only a guess as I have not used on before. Now, since the handle bar switch, when depressed, is grounding out, this would leave me to believe that there is (or used to be) an existing switch that is connected to the cut wire. This is then pushed to energize the cut wire to 6+ voltage. This actually works if the other wire (original crimped terminal) is hooked up to ground or not, so it's my guess that the solenoid gets its ground through the already-grounded speedometer housing. Now, if anyone has a similar bike and can simply remove the dash to snap a photo, that would be great! Thanks for any and all information.

ETA: It would be nice to simply use the original switch, reconfigure it to simply make a connection between the existing wire in the handle bar and the small terminal in the switch (not simply short to ground). Hmmmm..................

[FUUN063]

OK, here's what it took. An old 6 volt relay. I wired a positive to the relay with a small jumper to energize the other side. Then, I wired up (for the ground) the right side horn lookin' switch. This switch stays open (no ground for circuit) until it is pushed against the handlebar, completing the circuit. The solenoid then pulls in on the speedometer and it works. I don't think it was ever hooked up! Trip works, too, to return it to normal function. Yay. Also, to remedy the wandering needle above 30 or so mph's, I took the cable all apart, cleaned it and lubed it, then put it back in properly. Works great! All done. Stay safe.

[Rubone]

Seems like lots of work to get it going. That isn't how it is configured stock. Mine on my '44 UL has worked fine for the last 39 years since I installed it and wired it as factory. But if you like it that way OK.

[FUUN063]

It literally took ten minutes to actually wire it up. But, that's because I couldn't understand how the other "horn switch" (which grounds when pushed) makes the speedometer solenoid work (needs a positive to activate it, grounds through speedometer/dash). If there's something I'm missing, please let me know. This is the first I've encountered with this set up. The HD Servi Car manuals I have don't include the wiring diagram for this option. It only shows the wiring for the speedometer light, no other wires.