My speedo bounces a small amount. I noticed that if I turned the
speedo by hand using a small screwdriver, there was a brief increase in
turning force required every few turns. It was when this increased force
returned to normal that the needle seemed to bounce slightly.
I disassembled my speedo, and figured out that the needle
bounced slightly every time the odometer moved the tenths indicator by
one step (e.g. 1/10 of a mile). There is a small drive dog that engages
the gear for the odometer every 1/10 mile. When the dog engages the
gear, the turning resistance would increase slightly. I think that when
this occurs, there is a small mount of windup in the speedo cable. When
the odometer finishes rotating and the drive dog clears the gear, the
cable springs back causing a slight bounce. Maybe 2-3MPH.
I decided this was probably normal (but maybe not?) and never
did anything to fix it. Others can chime in here, but look to see if the
needle bounces when the tenth indicator moves. If so, then it is
probably normal. I say probably because I have not checked other TR6s to
see if they exhibit this. It may be a little oil or a small tweak would
eliminate even this small bounce.
When I was in my speedo, there were other things wrong that I
repaired and the bounce was the least of my worries. My high beam
indicator lens had fallen off and was rattling around in the bottom of
the speedo, and the lower needle stop was MIA. When I got those things
fixed, I called it good and buttoned it back up. Call me lazy, but
that's my story and I'm sticking to it.
From: owner-6pack@Autox.Team.Net [mailto:owner-6pack@Autox.Team.Net] On
Behalf Of Sally or Dick Taylor
Sent: July 27, 2007 11:17 AM
To: Bruce Moxon
Subject: Re: [6pack] Bouncing Speedo
Bruce---Sometimes when a bouncing speedo needle persists, it is good to
take the cable and what drives it out of the picture. A length of old
speedo cable cut to about a foot long can test the speedo unit itself.
Chuck the cable up in a drill motor, screw it onto the speedo and spin
it. (I don't recall whether I used a reverisble drill motor or not) A
short length of tubing over the cable will keep it from kinking.
You can do this while your carbs are off!