Bouncing speedometer needle: Possible causes?

challenger · Posted: Thu Feb 03, 2011 10:18 am Post subject: Speedometer?

My tachometer was doing the same thing at 5-6,000 rpm. Not a very difficult problem to solve. Simply unhook your speedometer cable, unbolt the speedometer and carefully flip it over (no need to remove the wiring) so the cable drive hole is straight up. Then add about 5-6 drops of light weight oil. I used some 3 in 1 oil. Let it sit for a couple of hours. Turn the speedometer over, re-assemble and ride! That should cure it.

jws3

Well, for the bike's speedo, that is!

Called "Foreign Speedo" in California based on comments here & on other vintage Japanese bike forums. Seems like decent people. "Bob" says that he's received many that people tried to repair after mangling the rolled trim ring on the bottom. For roughly $100 +/- it didn't seem worth the risk of wrecking something I can't easily replace and which has the original miles still on it. Yes, I can get the ring off it I try, but Bob tells me they have an "unroller" which does it neatly.

Even if its something simple I'd like it checked and re-lubed after 32 years of use. Not worth scratches or damage, so off to UPS I go.

skungheeney · Posted: Fri Feb 04, 2011 1:39 am Post subject:

I had my YDS3C speedo professionaly repaired when a needle snapped, they have a machine that unrolls the bezel to gain access to the working parts, all the numbers were cleaned, the needle was re-inforced to stop another break and new silicon was added and the bezel was replaced, if your speedo is rare like mine then I suggest you have it done properly.

JG122 · Posted: Fri Feb 04, 2011 3:01 pm Post subject:

that's a unique speedo/tach, thanks for posting the pic

sanctumbarbosa · Posted: Tue Mar 08, 2011 5:23 am Post subject:

The needle movement was damped by a coiled tension spring. Those springs lose tension over time and permit the needle to float around. A rough road probably makes it bounce around a lot. You might try an tool shop for repair or discover a new tool. My GT500 tach did the same thing, so I do know what a pain it is.

jws3

Based on research, I sent my 1979 Speedometer to "Foreign Speedo" in San Diego, CA. Although I haven't been able to test it, it arrived refinished and looking flawless. They were able to separate the unit by gently unrolling the lower flange and restore it to factory appearance.

According to the man I spoke with, my speedo was simply old and with long encrusted lubrication. The internals looked good, but the bouncing was a sign that metal to metal contact was starting. I'll test it in the Spring and hope to get another 30+ years out of it. He did advise that long periods of non use aren't good.

skungheeney · Posted: Tue Mar 08, 2011 12:57 pm Post subject:

The spring is only there to send the needle back to the stop, there is a little cartrage of silicon which slows (dampens) the needle when accelarating and de-celarating.

geck0 · Posted: Sun Apr 03, 2011 1:58 pm Post subject:

I had thr same problem. I went to the front tire. the tab that turns on the pinion was bent. thats all it was

dorT500 · Posted: Sun Apr 03, 2011 2:57 pm Post subject: