Is it possible to dissassemble a speedometer?

[2004Tiger]

I was investigating why my speedo did not function (speedo only, all other instruments work except odometer) and after verifying the sender installation, fuses, and repairing two broken wires in the sender cable, I found one connection on the back of the speedo loose. The lug was loose under the screw head, so I gave the screw a twist and it broke off inside the speedo. Apparently the factory had cross threaded the screw and the torque necessary to clamp the lug was more than the screw could take.

So now I want to dissassemble the speedo to fix the screw. It is not apparent how to do this. Please help.

Backing up a little in explanation, my speedo was intermittent. I found nothing amiss in the fuse box or the sender. With ignition on and front wheel spinning, I could jiggle the sender cable and get a bump on the speedo needle, but not in a repeatable fashion. So I found and repaired two (of the three in the sender cable) broken wires. They were broken just below the triple connector behind the R-F headlight. Of course now I expected the speedo to work, but it didn't, and no amout of jiggling would cause the needle to bump. I verified continuity in all three wires through the connector. I proceeded to poke around and found the loose lug and broke the screw. I can cob a fix with a self-tapping screw in the plastic speedo housing, but I would rather do it right.

Also, frustratioin set in when I made a temporary connection at the broken screw and the speedo still doesn't work. That was not the problem.
Why doesn't it work? Now I disconnected the battery to reset the computer. What else should I look at? Thank you for your help.

[oxnsox]

You may have done these things and eliminated them already but...
You have 3 wires...
At the connector from the speedo you should be able to measure a voltage on 2 of them. Do this with the sensor unplugged.
One of these will be the Black wire, can't tell from my Haynes manual which other one to use, but guess its probably the black/yellow.
Given your problem with the screw terminal at the speedo you will have to measure one (or all) of the wires at that point as it will be easier.
The sender works by sending a voltage down 2 of the wires and pulses, related to wheel rotation speed, will come back up the other.

If you can measure volts ok on 2 of the terminals, plug the sender unit back in and check the volts again.. It should stay about the same.

Given that the unit was working intermittently, either the broken terminal on the speedo means there is now not internal connection at that point (most likely)... or your other work has created a problem.

The broken terminal is the most likely one... so its either not sending volts down to the sender or not reading the signals coming back up.

Beyond that I can't help

[2004Tiger]

Thank you. I will measure voltage with my DMM. I charged my battery overnight and reconnected it this morning.

I used a short sheet metal screw to install the offending wire lug behind the speedo, measuring carefully to ensure the screw made contact at its tip inside the speedo.

Doing as you suggested, with ignition on, I measured 10.8 VDC from black to black/red and 0 volts from black to orange. Then with triple socket connected and front wheel spinning I measured 9.3 V on one pair and a fluctuating voltage (0 to 4) on the sister pair. This tells me the sender is providing a pulse. Good to know.

During the time I measured the pulse, I had no reaction at the speedo needle. Do I need a new speedo? Can anyone tell me how to troubleshoot this speedometer? If I knew the normal voltages at the various terminals I could track down a broken wire, or know that with normal voltage present I definitely need a new speedo.

Is it possible the previously intermittant speedo function was simply the instrument giving up its ghost? I found and fixed two bad wires but the non-repeatable nature of the former intermittant operation says something else is amiss. Now no speedo reaction at all so I suspect another bad wire.

Two days now and I'm getting a little crazy. Who has a spare speedo for sale?

[2004Tiger]

Update after more investigation.

It works. I verified continuity in all the speedo connections and reasoned that it should be working. Spinning the front tire, I kept an eagle eye on the speedo needle and it comes off the peg. I expected some sort of needle jump because that's what I saw previously, but now thinking logically, with continuous connections the needle will rise slowly.

I'm going riding. Thanks for your help Oxnsox.