CB77 speedo noise

[Merz64cb77]

I took my 67’ CB77 out for a ride today and had some erratic speedometer movements. The mph were way off and I could also hear a wheezing or whine noise. I’ve checked the cable and drive gear on the front wheel and both are greased and the wire rotates well. I intend on completing a drill test but am concerned about the noise and don’t want to break anything.
Any ideas what the noise might be from?
Thanks

[G-Man]

Usual culprits are either the cable or a dry input bearing on the speedo.

Put a couple of drops of oil into the input bearing and see what happens. Don't overdo it as the oil can mess up the speedo internals.

If all else fails the speedo needs to be stripped, cleaned and re-lubed.

G

I took my 67’ CB77 out for a ride today and had some erratic speedometer movements. The mph were way off and I could also hear a wheezing or whine noise. I’ve checked the cable and drive gear on the front wheel and both are greased and the wire rotates well. I intend on completing a drill test but am concerned about the noise and don’t want to break anything.
Any ideas what the noise might be from?
Thanks

[Merz64cb77]

Thanks G-Man

What would be the issue with the cable?

For the input bearing should I use any particular type or weight of oil? I read brake clean might be a good idea followed by a very thin oil.

If all else fails how difficult is stripping the speedo? I’d like to do the repair myself and avoid having to send it out to foreign speedo in San Diego.

I know a person selling a stripped and cleaned one for $250 CAD. So I could go that route as well as my last option.

[DJM]

I had an almost identical problem with my CL77 a few years ago, noisy and erratic and didn't return to zero too well either.

Put your speedo face down on a flat surface and drip TWO DROPS (no more) of light oil onto the cable input, try and get it between the stationary threaded part and the centre with the square cable recess in it.

Leave to stand overnight.

I also suspected that my inner cable was a shade too long even though the cable was brand new a genuine O.E.M. Honda part.

I found a small O ring that would just fit inside the 'end nut' on the cable and dropped that in when I put the speedo back on the bike, this effectively lengthens the outer cable by a couple of millimetres or shortens the inner cable, also it stops the 'nut' coming undone!

I could have thrown a heap of £££ at this problem but my quick fix worked out really well. Years later the speedo is still fine, no more screeching noises, reads rock steady at all speeds, is accurate and returns smoothly to zero as soon as the bike stops.

In fact even though over fifty years old it performs just like a new instrument, one of my better outcomes!


Hope you are as lucky with yours but if not it won't have cost you anything.

[Merz64cb77]

Hi DJM,

Thanks for the information. This helps a great deal to know that someone has been in my shoes before and was successful with a fix. I’ll be thrilled if mines turns out like yours.

Good news is both the tach and speedo passed the drill test but I still heard the noise so I followed your instructions and placed two drops of light oil between the centre/outer threads. The instrument is resting flat on the kitchen counter and will check it in the morning.

I have a feeling that my cable may also be a little long. I have two cables but one is louder with the drill test than the other so I’ll see if I can find a small o-ring as you did.

I was thinking that with only 11,500 miles on the speedo/tach it should work just fine.

Thanks again for the reply.

[G-Man]

Merz

Make sure, as Dennis said, that the oil goes between the center section and the threaded boss that the cable attaches to. This is a steel shaft running in an aluminum housing.

The mileage on your speedo is of less significance than its age or the environment that it's been in. The lubricants will deteriorate over time with no usage, at all....


Good luck!


G

Hi DJM,

Thanks for the information. This helps a great deal to know that someone has been in my shoes before and was successful with a fix. I’ll be thrilled if mines turns out like yours.

Good news is both the tach and speedo passed the drill test but I still heard the noise so I followed your instructions and placed two drops of light oil in the centre. The instrument is resting flat on the kitchen counter and will check it in the morning.

I have a feeling that my cable may also be a little long. I have two cables but one is louder with the drill test than the other so I’ll see if I can find a small o-ring as you did.

I was thinking that with only 11,500 miles on the speedo/tach it should work just fine.

Thanks again for the reply.

[Merz64cb77]

Thanks G-Man. I put the oil where you and DJM said. Hopefully it does the trick.

Environment was in a garage for 20+ years with no movement so I bet the lubricants have deteriorated.

I’ll post tomorrow with the results. Fingers crossed.

Thanks again