Resetting a speedometer to 00000

By Larry Cargill

There has been a bit of talk on resetting a speedometers odometer to zero again or any other mileage setting your looking for. So since I'm resetting one to 00000 for a cx500D that I'm building I thought I might as well take pictures of the steps it takes and post them here for you all to refer to. The speedometer I'm doing is from the custom style with the separate gauges. The same process works for the Std. style as well. But it's a lot more difficult to reassemble the two halves of the Std. style gauges than it is to do the type I'm showing here.

OK, here's the specimen I'm resetting. The chrome band that connects the two halves needs to be cut to get the assembly apart. I've seen people pry up around the back side of the ring to get them off but I prefer this method. It looks much cleaner in the end. I'm using a Foredom with a flex shaft that has a very thin cutting wheel on it to cut the band. But there are other ways to cut the bands.

With the band cut you will need to use a thin knife or scrapper to pry the two halves apart. Be patient and don't force it too hard. These have been pressed together for 30 years plus and need to be coaxed slowly.

After the two halves are apart you need to take out the two screws that hold the main unit into the back half. Sorry I forgot to take that picture. But the screws are next to the drive unit that the cable goes in.

Now you need to remove the screws that hold the face plate on. Be careful not to slip. The face is plastic and you don't want to break it.

Now comes the tricky part. Getting the needle off. They are pressed on pretty tightly usually. If you try to pry it off between the plastic face and the needle you take a chance of marking things up or breaking the needle. What I do is to put a screwdriver UNDER the plastic face plate just under the needle and twist it to pop off the needle. Be careful where you place the screwdriver though. You don't want to pry against any plastic parts like the rollers with the #'s on them.

While I'm writing this I thought that the reset procedure COULD possibly be done without pulling the face plate and needle off. I'll give that a try on the next one.

Now on the side you'll see a copper clip holding a spring and plastic collar in place. Push this off with the edge of a flat screwdriver.

Here is what the clip looks like.

Next you'll see the second clip that holds the numbered rollers together tightly. Take this clip out too.

Now is where you can reset the rollers to the # you choose. Start from the left side by sliding the roller to the left. This disengages the gearing in them and allows you to roll it. Be gentle. They tend to want to catch as you turn them if they are not pushed totally away from the adjoining roller next to it. When you get the one moved to the # you want, slide the next one over and rotate it to what you want. This is done with each roller one at a time from left to right.

When your done with all of them you'll end up with a gap between the tenth # roller. This one is engaged to a metal gear and isn't worth trying to move.

Now you can reverse the clip removal steps and put it all back together. When I'm done I always test the unit with a drill driven in reverse to make sure it all works for a mile or two. Believe it or not you can also reverse that by running the drill forward before you put the needle and face back on.

A word of warning! Be careful when you are pushing the clips off. Pressing it down on the bench like I did will break the alignment tabs for the trio meter. I'm lucky that this won't effect the unit from working since the actual lock is up against the metal plate of the assembly. These pieces are used on both sides of the speedometer. So I got lucky that it's not going to effect the function of the speedometer or the trip monitor.

With the unit and face plate screwed back in the next step is to set the needle in place. I use a drill with a section of cable that I use to drive the speedometer or tach before I take them apart. The speed is just under 35mph usually. So I set the needle on the stem very lightly and run it up to see what it's sitting at at that time. If it needs to be adjusted I can move the needle down or up depending on the need. This one needed to go down. So I put the needle on the underside of the peg and pressed it lightly so I could move it to the other side and test it. When it's at the correct setting I just simply press down harder so it will stay permanent.

After the glass inside is cleaned and I dab a tiny bit of oil on the bushing that the needle rides on as well as the inside of the input shaft, It's time to put the top back on and assemble it. Since I used the cutoff wheel to cut the band off I simply line up the cut marks to get it back in position.

When cutting the band off you'll find that they expand a bit. I gently roll the band with my fingers to get the gap to close up. That way there's no outward tension trying to open it back up after it's glued back on.

Next I put a thin film of GMS, (GM sealer that you can get at any GM dealer) inside the rim of the band. This will ensure it stays water tight and will also keep the band in place. This stuff turns to the consistency of pure rubber when it dry.

Now just slip the band on and put a large adjustable clamp around it to hold it in place over night. As you can see I used tape around the edge since the cover has new paint on it. The sealer will squeeze out a little around the edges. That's what you want so you know it's sealed well. When it's dry the tape line makes it easier to clean off the excess.

Well, that's about it. Let it cure good, clean it up and it's ready to install the next day with the desired odometer setting.

Hope this helps with your next project.

Larry

Larry not to discourage anyone but there is a less involved way if you don't want to take the speedo needle and face off.

Press firmly on the number rollers with your thumbs and then press down and forward in the directions the numbers should roll and they will fall into place. I do each roller separately. Once I get to the number i want I rock it back and forth to make sure the plastic or metal piece springs back.

Freshly taken pictures from a tripmeter. The concept of the thumbs works the same as turning a trip meter knob.