Speedometer Repairs

[dropbear]

I had a learn as you go experience with this today and thought I would do a write up in case it's useful to anyone else.

I'm working through a recently purchased GS500. One issue was that the trip meter does not work correctly. As this is very useful for keeping track of fuel, I decided to address it, but didn't want to buy a new speedo, given that the speedo and odometer are working. I bought a secondhand speedo from a wrecker for next to nothing, because it had a damaged housing, but functional speedometer, odometer and trip meter. The damage to the housing was that the studs mounting this speedometer into the instrument cluster had broken off. So worst case scenario is I cannibalise a good speedo out of both and best case scenario is I have a good speedo and a spare. I managed the second by the steps set out below.

1. Equipment. With the speedo already off the bike, you'll need a flat head screwdriver, standard phillips head screwdriver, precision phillips head screwdriver, needle nose pliers and eye glass cleaner/cloth. An old screwdriver with rounded corners is best, as sharp corners will notch the lip of the bezel.

2. Caution. Proceed slowly and with great care. Apart from the delicate easily broken parts you're working with, you could potentially do cosmetic damage which will mar your good work.

3. Remove the bezel from both speedos. There are some videos on YouTube about how to do this, but I found that there is a knack to it which makes the job much easier and which is kinder on the speedos, which isn't apparent from those videos. First, invert the speedo on a soft surface (a mouse pad is good) and work around the back of the bezel with a flat head screwdriver, gently prying up the lip of the bezel every few millimetres. One lap should be sufficient. I did many laps first time, but that was slow tedious work and scratched up the white plastic housing. The second time, after the first lap, I levered the shaft of the screwdriver off the white plastic housing, pushing the handle towards the housing, so that the (vertically aligned) blade of the screwdriver pushed out against the lip of the bezel (which was no longer horizontal) in a horizontal direction. This method took a quarter of the time and didn't scuff the plastic housing.

4. Some of the videos recommend using a hose clamp around the bezel to prevent the bezel spreading as the lip lifts, but I didn't do that, as I found it unnecessary and was concerned that it could scratch the bezel. If I was going to do that, I would cover the bezel with masking tape to give it some protection.

5. Keep going until the lip of the bezel is vertical enough for the bezel to be pulled off the white plastic housing. There will be some spring in it, so it's not going to go back on like this and you might want to work around the lip of the bezel one more time with a pair of needle nose pliers, bending it up enough so that you should be able to get the housing back into the bezel when you're finished. I've attached a picture of how mine looked when finished.

6. Remove mechanism from housing. Remove knob with a precision phillips head (from end of knob), then its just 2 screws at the base and lift out.

7. Speedo with broken housing. I simply swapped the white plastic housing with the one from the other speedo, then put this one back together. When putting it back together, take care to clean out any dirt and debris and clean the dial and inside face of the glass lens. You wont be able to do this when it's back together and you won't want a fingerprint on the inside face of the lens to be a constant annoyance.

8. Speedo with bad trip meter. More work here. As to the broken housing, there were two small holes in the centre of the circular cavities where the studs mounting the speedometer to the instrument cluster were situated. I drilled these out to 5 mm and ran an M5 40 mm bolt through from the inside of the housing, secured on the outside with an M5 nut. There's plenty of room inside for the head of the bolt. To simulate a stud, I put two M5 nuts on the bolt spaced about 5 mm from the end and locked them together. I've attached photos of the original and modified mounts for comparison. As to the bad trip meter, it appeared to have taken an impact through the knob (although the knob was intact), pushing the dials together so tightly that they couldn't turn independently. I gave them a very slight separation, which solved that problem. Putting it back together - same as other speedo.

9. Flatten bezel lip. I went round one lap with a screwdriver pushing down the lip and securing the bezel in place. After that, I did a couple more laps pushing down the lip with the strike end of a cold chisel. I was considering using a piece of dowel and a rubber mallet, which would probably be okay if you proceeded with care, but I didn't want to take the risk.

10. Have a beer while you take pride in your work.