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[Andy C]

Why do these thing read so vague with the needle swinging all over the place?

Looks to me like it might be something doing with the damping, or lack of.

My solution (for years) has bene to fit a wired bicycle speedo, but I really would like to run the bike with a proper speedo - what's the solution?

[papasmurf]

Why do these thing read so vague with the needle swinging all over the place?

Looks to me like it might be something doing with the damping, or lack of.

My solution (for years) has bene to fit a wired bicycle speedo, but I really would like to run the bike with a proper speedo - what's the solution?

Replace the cable with a British one?

[Haggis]

I took one apart just for a look.
The drive cable spins a magnet, nothing unusual.
A metal cup with a spindle up to the needle, so the magnetic field drags the cup round to give a speed reading.
BUT, to hold the needle and its spindle at the correct height the bottom end of the spindle rests on a hardened metal disc in the centre of the magnet.
So the needle is not only moved by the magnetic force but also by any friction between the spindle and magnet.
The metal disc in mine looked like it had been tapped into place with a sharp screwdriver and had deep scratch across it. This was catching the spindle every revolution and causing the needle flick round.
Not easy getting them apart and back together again but they're cheap enough to experiment with.

[Adrian]

Replace the cable with a British one?

The drive ends are the same but the top ends aren't. I think the Indian instruments use an M18x1.5 thread where the cable screws on

A.

[Andy C]

Haggis - thanks for that info.

I have a spare one so may well take that apart to investigate, seeing that needle constantly flicking around I find really annoying.

[Wheaters]

The speedo head itself might be OK; a wandering needle is often caused by a sticking cable (the inner can slightly wind up then suddenly release).

[Andy C]

The speedo head itself might be OK; a wandering needle is often caused by a sticking cable (the inner can slightly wind up then suddenly release).

Good point I have to be honest and say that I have never thought the cable might be the issue - something else to check.

Are the gearbox's reliable? mine is the one with the grey plastic housing.

[Daiwiskers]

The cable is always a good place to start but if it has been over lubricated in the past grease or oil may have found it's way up into the speedo causing the problem

Hopefully it's just the cable catching or dried up grease in the cable

The Indian speedo's don't seem to be the most accurate and do tend to waver quite a bit

The drive unit's seem to be pretty good but our hosts do sell a better metal one

Hope this helps Dai

[Andy C]

Dai.

Cable was quite dry so I applied some lubricant to it, improved the wavering hand a lot but get above 50 and it swings around all over the place, probably open it up and take a look.

Checked the calibration of the bicycle speedo last night and gave it a new battery, works fine and is of course accurate !!

[ChrisD]

I had similar problems with the OEM speedo on my 1996 Indian bullet. So I bought a new speedo from Mr H. As this looked like a genuine UK Smiths chronometric, I knew I could trust it.
But it didn't solve the waving issue although it didn;’t over-read quite so much. BUT I found it very difficult to continue for any length of time at averaging the highest and lowest waves, which logic said should be close to the truth.
Then I thought it was the inner cable sticking in the outer. So I tried it dry, oily, well-greased, lithium greased, lard, with and without the small washers - to no avail.
Then I believed the "too long" cable story which pushed up the speedo cup (no, not that sort of speedo), so I cut 3mm off the speedometer end of the cable with my trusty dremel. I believed this would be the answer because under the close inspection which I had finally given to the speedo, I could see the needle bobbing up-and-down as the wheel spun and the needle waved. This also didn't help.
So I stuck both speedo’s onto an electric drill to see if I could replicate the waving. Nope, they both held perfectly stable readings, although the OEM speedo read ~25% fast.
By this point, some 10 years later, the penny had finally dropped that I was on the wrong track.
So I jacked up the bike and watched the speedo drive as I spun the wheel. I could see where the cable screwed in that it was moving backwards and forwards. So I thought long and hard about circumsizing the other end of the cable, but logic prevailed and I unscrewed the outer cable and removed the inner and noted with surprise and delight that the mechanism was moving backwards-and-forwards in time with the waving. Some hideous manufacturing defect in the OEM part meant that maybe I could finally solve the waving.

I expect you are waiting for the end of the story.

Sorry, I cann't afford a new drive especially since I have a nice bike speedo which is great - except it doesn't like triple digits. So, as I am in a kilometer country (South Africa), that means I have good speed indications up to just over 60mph which is plenty fast enough anyway for this old codger.
Cheers, ChrisD
PS: sorry for the short hijack