Problem with Speedo instrument flickering

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Lorenzo

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Mar 27, 2011
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I recently broke my speedo drive, which broke the speedo cable. Then I had to thrash both while I was riding on a long trip.
Now I replaced the speedo drive (which was anyway a repro) with an original one which I cleaned, greased and mantained, as should be. Also, I added a new Vanhill cable.
Now the speedo instrument is working, but flickering a bit too much from before.. I did some trials with other instruments and it seems the cable and the drive are ok..
Should I send the speedo for maintenence or perhaps I should check something else before?
what is your experience?
thanks for helping!
 
Maybe just try a light oil , it could be winding up then releasing with the grease , causing the flickering. Cheers
 
Lorenzo said:
I recently broke my speedo drive, which broke the speedo cable. Then I had to thrash both while I was riding on a long trip.
Now I replaced the speedo drive (which was anyway a repro) with an original one which I cleaned, greased and mantained, as should be. Also, I added a new Vanhill cable.
Now the speedo instrument is working, but flickering a bit too much from before.. I did some trials with other instruments and it seems the cable and the drive are ok..
Should I send the speedo for maintenence or perhaps I should check something else before?
what is your experience?
thanks for helping!
Click to expand...
Could be a problem with new cable where it connects to speedo instrument. I believe there are some different cable end shaft lengths and not all will fit your speedo correctly. Compared it carefully to your old one.
You can confirm if the instrument is ok by fitting a square drive bit into a power drill and inserting into instrument. Running the drill to turn the instrument should show smooth needle movement. If not, then repair or replacement seems the best option.
 
Tornado said:
Could be a problem with new cable where it connects to speedo instrument. I believe there are some different cable end shaft lengths and not all will fit your speedo correctly. Compared it carefully to your old one.
You can confirm if the instrument is ok by fitting a square drive bit into a power drill and inserting into instrument. Running the drill to turn the instrument should show smooth needle movement. If not, then repair or replacement seems the best option.
Click to expand...
I tried with a drill and the movement is smooth as it should be. At the same time, I can witness the new cable is a good quality one, which is right for the instrument..
 
Lorenzo said:
I tried with a drill and the movement is smooth as it should be. At the same time, I can witness the new cable is a good quality one, which is right for the instrument..
Click to expand...
The cable end can be too long causing that. Also, you must have no lube in the last 2" of the cable and of course, not grease.
 
Lorenzo said:
can you tell how much should be out on each side?
Click to expand...
When I have the rebuilt, they come back with a sticker that says 1/2" (12.7mm) and they say the internal mechanism is 9/16" (14.3mm). So, this is the part of the cable that goes into the speedo, not the amount sticking out past the "nut". The drive end doesn't matter as far as I know.
 
On the end of the cable there should be a stopper on the cable to stop the cable going too far inside the speedo when done up, well on the original cable anyway, a lot of new cables don't have that stopper on the end of the inner cable, my original cable has a big kink in it under the bike I have replace it with new cables and had the flicking problem, very hard to adjust the right amount of cable without that stopper and the new cables had short life, so I put the old original cable back on even with the kink in the cable it still work without any flicking of the needle.
I am still running the original speedo drive, but my original speedo got damaged in the great fire of 82 and been running a Triumph speedo but I had the original speedo rebuilt about 12 years ago but I am still running the Triumph speedo.

Ashley
 
Lorenzo said:
I tried with a drill and the movement is smooth as it should be. At the same time, I can witness the new cable is a good quality one, which is right for the instrument..
Click to expand...

You should measure the depth of the instrument "socket" that accepts the inner cable end, then measure the inner cable end from the outer cable ferule cap (not the threaded section) to the end of inner cable. It needs to be about 1/16 of an inch shorter than the socket depth, otherwise it will push too deeply into instrument and cause problems. Lots of reports of new cables having incorrect end lengths.

Also try the drill on the speedo gear drive end and see what happens at the instrument end. Sometimes the cable bending along the path between instrument and drive is enough to cause flicker.....need to check alternative pathways, minimizing bends.
 
I have had my 73 Commando for over a year.
The speedometer is untouched.
Is itan idea to take it out, turn it upside down, put a drop or the right amount of oil into the drive and let it wick down with gravity and lube the drive bushing?

Dennis
Vancouver
 
DennisMo said:
I have had my 73 Commando for over a year.
The speedometer is untouched.
Is itan idea to take it out, turn it upside down, put a drop or the right amount of oil into the drive and let it wick down with gravity and lube the drive bushing?

Dennis
Vancouver
Click to expand...
The drive definitely needs regular greasing via the zerk fitting. I believe the original decal ln the drive states every 500 miles?

Not the actual speedometer!
 
Recently had my speedo refurbished by Joel Levine. He recommends 5/16" to 3/8" of cable, beyond the ferrule, at the instrument end. This is for later magnetic drive instruments, not chronometric.
 
I've thought of doing that myself but all readings/ talk of that say no don't do it .
A rebuild is pricey with a new glass and bezel required to be fit by someone with the proper crimp roll on tool . I think they fit a new core or bush , with a little grease ? You'd think after 50 or so years any lube would have dried up .
To be honest I did it once to a speedo instrument in my younger days . Unit upside down , a single drop of thick oil to the bush and let it absorb overnight , upside down . Seemed to work fine on reinstalling , no oil particles flung about . In the end it was a cable tip that was too rounded that was the issue . That was then . Nowadays I run the Smiths electronic one that comes with it's own issues .
 
I measured the inner cable from the outer cable ferule cap to the end of inner cable and it is 12mm: is it right?
additionally, I noticed that when I tight the cable to the clock, while moving the cable in the back it is moving also the dial of the clock.. is it normal?
thanks for helping!
 
It looks like your cable is protuding too much try to fit a washer at the end of your outer cap ferrule , another question what your speedo plain green globe or striped green globe ?
 
DogT

Thread 'Speedo cable'

My speedo cable has a round stop on one end pressed onto the inner steel wire. Which end does that go on, the gearbox, or the Speedo end? I've been having trouble with the speedo dropping out now and then, put the speedo on a drill and it seems steady. Turned the wheel while holding the speedo end of the cable and it doesn't seem to jump or miss at all. Maybe if I have it in backwards, it's getting loose? I assume the knurled end also goes to the speedo, like the tach.

Dave
69S
 
Lorenzo said:
I measured the inner cable from the outer cable ferule cap to the end of inner cable and it is 12mm: is it right?
additionally, I noticed that when I tight the cable to the clock, while moving the cable in the back it is moving also the dial of the clock.. is it normal?
thanks for helping!
Click to expand...
Depends on how much it's moving. The internals are rubber mounted with screws and grommets in the underside. It should move but only a tiny amount.
 
marinatlas said:
DogT

Thread 'Speedo cable'

My speedo cable has a round stop on one end pressed onto the inner steel wire. Which end does that go on, the gearbox, or the Speedo end? I've been having trouble with the speedo dropping out now and then, put the speedo on a drill and it seems steady. Turned the wheel while holding the speedo end of the cable and it doesn't seem to jump or miss at all. Maybe if I have it in backwards, it's getting loose? I assume the knurled end also goes to the speedo, like the tach.

Dave
69S
Click to expand...
The pressed-on ferrule end of the inner cable goes to the speedo. Knurled end of outer sheath goes to speedo.
 
marinatlas said:
It looks like your cable is protuding too much try to fit a washer at the end of your outer cap ferrule , another question what your speedo plain green globe or striped green globe ?
Click to expand...
it is a striped green globe speedo: are they interchangeable with the same drive?
 
The cable protrusion only needs to be less than the depth of the slot so 1/2" in a green globe instrument should be fine.

The earlier green spot instrument cable needs to be no more than 7/16".


Problem with Speedo instrument flickering
 
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