Speedometer - Tech Design Works

When I “finished” my car I got an email from a Heinkel friend in England that basically said “Congratulations, now you’ll probably spend as much time adjusting and debugging as you did restoring!”. He’s been right so far.

One issue that has literally been in my face is the speedometer. It just doesn’t work. When I was rebuilding I removed the speedo from the casing and carefully lubricated it, then tested it. When I’m driving though, it looks like this:

GPS Speedo: 30; Heinkel Speedo: -0-

I’ve been using a free iPhone app as a speedo, and at this point I’m pretty good at estimating my speed within a few miles per hour with or without it. While the GPS speedo is useful for keeping the passenger occupied (and their mind off of my sometimes terrible shifting), wouldn’t it be nice to have a real speedometer and odometer?

The best way to test a speedometer is to take a piece of old speedo cable and attach it to your drill. Run the drill in reverse (counterclockwise) and see if the speed registers and the miles advance:

Speedo testing with Drill

On a good day I can get up to 40 miles per hour with my drill, which is almost as fast as I can drive!

Cruising at 20 MPH with my Ryobi Drill

Once I ruled out the speedo again, I took a short drive to see it the cable was actually spinning. In my case, it wasn’t. This means the problem is back where the cable attaches to the speedometer drive on the swingarm, or the connection of the speedo drive connection to the small chain gear that runs off of the engine inside the swingarm.

That’s a project for another day…