Speedometer needle jumping

[TexasKnucklehead]

Randall mentioning such a quick re-break, reminded me that I just replaced that cable. I was very careful to route the new cable the same way as the old one thinking that was correct. The cable came in thru the firewall, and went under the wiring harness, then up to the meter. I think it should go above the harness, and avoid that bend just below the meter. I already have a slight kink in the cable at the end near the meter. But re-routing allows my drill to turn the cable at a nice smooth 30mph. Any less, and it bounces, but not as bad as before. With it pulled out of the meter, it turns easily with no hangups. And with a short cable end stuck in the meter, the meter turns easily. Only with the added bend does it hang.

 

[toysrrus]

Hi There David,

I had a TR4 with the same problem.

Its always recommended to use graphite but as a quick fix; A friend of mine disconnected the cable at the guage.

He shot some WD40 directly into the rear of the guage & problem was solved!

LOL,

Russ

 

[davidk]

Finally got the speedometer to stop jumping. To quickly recap: speedo was working fine, ordered a new cable because the old one had paint overspray on it under the hood. With the new cable, the needle was jumping badly, worse at lower speeds. I ordered a spray moly lube, and sprayed down the cable. Still jumping. Removed the cable and sprayed on more lube. Still jumping. Removed the cable and lubricated with white lithium. Still jumping. Removed, greased and replaced two more times. Still jumping. I then compared the new cable end at the speedometer with the old and noticed that the nylon piece attached to the cable was sticking out about 1/16 on the new, and not at all on the old. I loosened the nut a couple of turns and no more jumping! I then removed the cable and used a fine hacksaw blade to shorten the nylon piece. Reassembled it, and the jumping is gone. I have attached pictures of the before, after, and the old cable. I will contact the vendor and let them know.

 

[CCURTISS]

I installed a new Moss cable and it worked great for about 20 miles then the spedo stuck at 38 MPH. After some more driving I heard a squealing noise so I unscrewed the cable while rolling and the spedo started working. I may have the same issue with the plastic sleeve, I will look at it tonight.

Thanks!

 

[DNK]

Just received a replacement from BPNW for one I bunged up the speedo end on. I will look at it too.

 

[TruCraft]

Installing my TRF cable was not a easy bolt in.
The cable would not go into the tranny.
I measured the square and it measured about (.126-.128") and had a few burrs.
The old one was about (.120).
I filed the cable to get it to about (.122)and made sure the corners were not sharp.

The cable protruded about 3/8" on the speedo end, controlled by the plastic part.
The tranny end was about 3/4".

Used Moly lube as you guys said "Motor cycle chain lube".
Installed making sure the cable had no sharp bends.
Took it out for a test drive and speedo worked great! Slight drifting 1-3 mph at certain speeds, probably normal.
Had it up to 75mph and it worked great.
Lyle

 

[Perrymip]

When I sent my TR3 speedometer to MOMA restoration service in Albuquerque to have it cleaned and repaired, they requested that I include the cable I intended to use, which indeed they modified. As I recall the ends of the cables commonly available were all slightly too long.

 

[prb51]

Similar to Perry.
The gent that restored/recalibrated my Speedo had me send the cable which he gutted (housing) and replaced with a new correct length/diameter inner cable. He always recommends this and told me that proper resistance is as important as free moving and the lengths of many on the market (tip from the ferrule) are too long.
Works perfectly, almost looks like it's electric.

 

[BobbyD]

When I sent my TR3 speedometer to MOMA restoration service in Albuquerque to have it cleaned and repaired, they requested that I include the cable I intended to use, which indeed they modified. As I recall the ends of the cables commonly available were all slightly too long.

I sent mine to West Valley Instruments and in my conversation with Morris he asked me to check how far the inner tip protruded past the housing. I wish I could remember the length but mine was about 1/16" too long. He'll only guarantee the repair work if the cable tip is the correct length. If it's too long it can cause internal damage over time and/or erratic operation. I included my cable with the speedo and he made a new inner cable and returned the old one. I'm sure this carries over to the tach as my tach makes a ticking sound. If I loosen the cable "nut" so that I can pull the tip of the cable back, the ticking stops.

The moral is......if the shop you're thinking of using doesn't ask about the cable.....find another shop!

 

[TR3driver]

I'm sure this carries over to the tach as my tach makes a ticking sound. If I loosen the cable "nut" so that I can pull the tip of the cable back, the ticking stops.

Definitely a smoking gun; and as noted it will eventually damage the works. I'd fix that sooner, rather than later !