Topic: Bouncing Speedo (BIG bounce)

[jakec]

On my 400, the speedo needle has recently started to bounce, and this is not wiggling but more like bouncing wildly from 0 - 120 (or whatever max is).

The behavior is normal up until about 55 mph, and then the needle will wander between 55 - 65 mph. After 60 mph the wandering gets more aggressive and the needle starts bouncing wildly the faster you go.

There are some factors that seem to affect it like speed, load, rpm, whether I'm turning, going up a hill, etc. The gauges are mounted in 100% stock way with brand new OEM cushions. The cable is aftermarket but it has only 1,000 miles or so and I cleaned and lubed it, then tested before making this post. The rest of the bike is also stock.

The reason I'm really concerned about this is because I had this happen once before (speedo bouncing around wildly) and the gauge and odometer eventually stopped working altogether. I would like to fix this issue before it breaks the mechanism again.

[seanbarney41]

So, this is likely not gonna help much...I have seen this behavior many times over the years and dozens of bikes and the result was either 1 of 3
     1.  Cable is bad or going bad.  Usually doesn't take long once a few threads have started to unravel for it to break completely.  Then your gauge will stop moving altogether.  Sounds like you have checked the cable pretty well.
      2.  Gauge has been sitting for a long time and mechanism is sticky and poorly lubed.  Further use may improve or it may just stay that way forever.
      3.  Gauge has something seriously wrong with it and the bounce is an indication of impending doom.  Even if the gauge is on the comeback trail, a particularly violent bounce can dismember the needle, requireing a full rebuild basically anyway. 

Gauge restoration is something I have a 0% success rate with, so I will usually just run 'em til they die, then replace with used, on my low value machines.  And if I ever have something worth restoring to that level, I would send it to a specialist like Lecram.

[jakec]

I have already had the gauges apart for cosmetic restoration, but never messed with the actual mechanical part of it. I have read many threads on here already saying yeah, you may need to take it apart... But never saying what you need to do once it's apart aside from clean and lubricate the internals.

I think it is possible that the cable that's on the bike now is the same one I was using when the first gauge died. It is interesting to see two gauges have the same problem on the same bike, whereas I have never had a problem with any other gauges aside from a slight wobble.

Who is Lecran? Maybe I can email them for advice. I'm not opposed to sending it in somewhere.

[pjlogue]

I would suggest you get a new cable.  The inner turning part of the cable is nothing more than a very, very long, tightly wound spring which can store energy if one end is bound up.  Once the energy stored is greater than the binding force it unleashes the stored energy.  I doubt it is the internals of the spedo but it is possible.  A new cable is the easiest and cheap route.  Make sure the receiver (part the cable inserts into at the spedo) turns freely and is greased.  Your cable from the front axle to the spedo should not have any sharp bends. 

-P.

[scottly]

If the part in the speedo that the cable turns is dry and binding, the friction will cause the cable to wind up like Pj says, and can damage the cable. I had a problem with a speedo that also made a bunch of noise along with a jumping needle, although the jumping wasn't as bad as yours.
http://forums.sohc4.net/index.php/topic,138221.0.html
I have also filled the small cap from a can of brake cleaner with motor oil, and placed the speedo threaded drive into it and let it soak overnight, but in that case the speedo was not mounted on the bike, so it was easy to prop it up over the cap.

[seanbarney41]

Lecram=Cb750 Faces   ...does world class complete gauge restoration

cb750faces.com/en/content/7-gauge-restoration-services

He is a member here.

[seanbarney41]

If the part in the speedo that the cable turns is dry and binding, the friction will cause the cable to wind up like Pj says, and can damage the cable. I had a problem with a speedo that also made a bunch of noise along with a jumping needle, although the jumping wasn't as bad as yours.
http://forums.sohc4.net/index.php/topic,138221.0.html
I have also filled the small cap from a can of brake cleaner with motor oil, and placed the speedo threaded drive into it and let it soak overnight, but in that case the speedo was not mounted on the bike, so it was easy to prop it up over the cap.

I am gonna try this with some of my erratic gauges.  On my gold cafe bike, I use a home made tach bracket which needs to have some better shock absorption engineered in, as ever since that bracket was used, tachs have not lasted long.  I think good shock proof mounting may be important too.  So, make sure all your rubber mounting parts are in good order.

[Medyo Bastos]

Oh that kind of speedo! I was afraid to click this post!


Sent from my iPhone using Tapatalk

[scottly]

Oh that kind of speedo! I was afraid to click this post!


Sent from my iPhone using Tapatalk

A binding SPEEDOMETER can trash a cable, but a bad cable can not damage a SPEEDOMETER; the drive at the axle maybe, but not the SPEEDOMETER.

[jakec]

I have ordered a genuine Honda speedometer cable and will install and report back.

[scottly]

Have you tried lubing the speedo like I mentioned yet?

[jonda500]

Lecram=Cb750 Faces   ...does world class complete gauge restoration

cb750faces.com/en/content/7-gauge-restoration-services

He is a member here.

Although it seems he can do good work, and while I had no intention of talking about it in the forum, I just have to say it briefly -
that guy ripped me off blind! - it was years ago and until recently I had been too angry about it to even visit the SOHC/4 forum...
John 
p.s. I will happily discuss the details with anyone who wants to talk about it but only via pm

[jakec]

Have you tried lubing the speedo like I mentioned yet?

I just removed the gauges and have them propped up sitting in shot glasses of 50/50 brake cleaner & motor oil.

[scottly]

It may help to lift them up out of the oil and spin the driven part with your fingers from time to time, as this helps work the lube into the bushing. I think the last time I used a bamboo skewer or something similar to engage the square cable hole?

[jakec]

Did I get the mixture correct? I checked on it 3 hours later and the plastic shot glasses I used melted. Luckily everything eas propped up so the gauges didn’t fall over.

Should I try again with same mixture and glass shot glasses?

[scottly]

Don't use brake cleaner, just oil!! Hopefully the melted plastic won't gum things up..

[jakec]

If they have I suppose I can just use more brake cleaner.

[jakec]

Ok so I am now using genuine cables on both gauges, and had oiled the gauges where the cable goes in (even though they were rotating freely before anyways).

I went on another long ride today and after about 25 miles it started up again. Not as bad as before but still bouncing around.

I felt the gauges for vibration while at high rpm and they do have a high frequency vibration going through them. I haven't ridden another bike yet to confirm if this is normal. As far as I know I have them installed correctly.

[jakec]

I have all of the rubber parts highlighted below

[bryanj]

On the 500 there was a modified clock "cushion" to reduce vibration and bounce, they definately need all the correct mounting rubbers, washers and collars etc

[The Lone Builder]

I had the same problem; not only was the needle bouncing all over the place, but it was not reading correctly. This lasted fro about 5-6000km before it packed up alto Gh there.

I replaced it with one off EBay and it worked for a little while, then started doing the same thing. I disconnected it before it packed up.

When I finished my ride, I sent the original off to a rebuilder and he said,

“It is indeed wildly inaccurate due to bush wear and inoperative hydraulic inertia dampers.”

I imagine the lack of damping would account for the bouncing.

I haven’t tried it out yet as I’m still waiting for the “furloughed” vehicle licensing office to get back into gear and give me back my original reg number.

[jakec]

Who did you have do the work? I may want to send mine in.

[jakec]

Also, does anyone know if the vibration is normal? I can't exactly test it because if I ride my other bike, which is unrestored, the variables will be different (older rubbers)

[lash]

Dont overlook the speedometer gear on the front wheel. The grease in there can get awful hard and nasty.

[jakec]

I installed the wheel last winter with only a couple hundred miles on it since. I will check that tonight though.

What I read in old threads on here was that the bounce would never be caused b the worm gear at the wheel. If it works at all (which it does 50% of the time) then the mechanism is working at that end.

[The Lone Builder]

Who did you have do the work? I may want to send mine in.

I’m in N Ireland and sent it to a guy in GB. I’ve since found another one who is considerably cheaper, and very helpful into the bargain.

Peter Bond -  guageman1@gmail.com - the first one
Peter Horton - peterhortongauges@gmail.com - the second (cheaper) one.

I installed the wheel last winter with only a couple hundred miles on it since. I will check that tonight though.

What I read in old threads on here was that the bounce would never be caused b the worm gear at the wheel. If it works at all (which it does 50% of the time) then the mechanism is working at that end.

I’d agree with that, although when I took mine apart, there was considerable damage on the teeth due to backlash.

[jakec]

Thanks for the suggestions. Although I will probably have to go through someone here in the US. I know there is at least one reputable guy out here although I can't remember his name.