Wombat speedo

[Bert44]

Hi,
I’ve been working on my 94 Wombat and was about to fit the speedo when I noticed that the needle was swung over to 100 and stayed there. There was also a load of spiderweb that I could see up the light fitting hole. I’d pulled an old Honda speedo apart after reading Bevman’s enlightening post so got stuck into the Wombat speedo.
From the photos you should see that a trip meter is just piggybacked onto the speedo. Also the problem was quite obvious - the thin clockspring had broken or dislodged from its holder. The end is held in place by a small steel stake which wedges the spring in place.
The only thing to watch when replacing it, is that the spring will pull the needle to 0 and not to 100.

[TheBevman]

Bert, glad to hear you've found your problem and that your undertaking the task. The clock spings seems to be the only point of "calibration" on these speedos. On of my speedo's clock springs was broken just before the spike too. I had to flatten the spike's hole to get it to bite, my spike was really in there (someone was an over-achiever that day) but it's working fine now. Haven't had a chance to see how far off the calibration is yet... I need to find one of those speed-trap trailers the police use to show your speed.

Does everything else on your speedo turn without binding?

Bev

[Bert44]

Hi, yes, everything turns nicely. I cleaned everything and used a light oil to re lubricate. It looks to me that the spring only controls the needle return and damping, not the actual speed. It looks like the magnet and drum controlled the accuracy of the needle. I guess the strength of the spring could act as a brake on that accuracy though. Time and a gps will tell.
Bert