Speedometer Not Working

[PhillyScott]

I was out for a ride and all of a sudden the speedometer needle and odometer on my Rockster stopped working. Checked all connections behind the instrument cluster and the bit that goes in to the final drive, but all seemed fine. Has anyone else had this problem?

Thanks,
_Scott

[grwrockster]

I haven't, but I know that forum member Riceburner has. I think he said that the 'ring' that the pick-up 'reads' in the rear drive bevel box had come loose, so wasn't turning with the wheel, so no speed indication on the dial. I'm sure though that RB also said that this was after he'd had the rear bevel box rebuilt to change a bearing - I've not heard of the ring coming loose otherwise.

As far as I can guess, the pick-up unit is probably little more than a magnet. The 'mag pick-up' sends a pulse to the speedo, which interprets the frequency of pulses and displays that as a speed reading (much like an ABS ring recognises when there is a lack of pulses relevant to road speed and works out that your brake is trying to lock - they are using the same tech for different tasks). Anyway, it's not unheard of for mag pick-ups to fail so it could be that. The distance or gap from the Mag to the ring it reads is also important - so if yours isn't seated properly or the face is damaged then that might be a cause.

After that, all I can think of is to check the wiring for continuity, and if that gets you nowhere i guess you've got to suspect the speedo unit.

I'm afraid a lot of this is conjecture on my part, and there is most likely others on here who can give you a better insight.

[sweatmark]

I was out for a ride and all of a sudden the speedometer needle and odometer on my Rockster stopped working...

Do you have Integral ABS or factory non-ABS bike?

[riceburner]

I was out for a ride and all of a sudden the speedometer needle and odometer on my Rockster stopped working. Checked all connections behind the instrument cluster and the bit that goes in to the final drive, but all seemed fine. Has anyone else had this problem?

Thanks,
_Scott

As GWR said - I've had this issue after a final-drive rebuild.

If your bike is NON-ABS and has the speedo pick in the final drive (sounds like it has) - then there's a castellated ring "pushed" onto the final drive hub that the pickup reads from.

Does the speedo needle "flicker" occasionally? If so - I would put money down that the ring has come loose. Occasionally it'll grip the hub again and start spinning.

Don't worry about the ring causing damage - mine was loose for 5 months over winter and nothing happened (I ride the bike daily).

What you can do, as a temporary fix, is remove the pick up block (1 allen bolt). then take a long screwdriver and gently lever the ring back onto the hub - you need to push the ring up the chamfer on the hub (towards the wheel) , turn the wheel 1/3rd, push the ring up a bit, turn the wheel 1/3rd etc etc until it's not moving.

Try to avoid using the edges of the pick-up access hole as a pivot point - you can damage the ally block and the o-ring on the pick-up block won't seal.

The proper fix would be to strip the Bevel box down and have it all rebuilt (do the bearings while you're in there). But MAKE SURE it's done by someone who's aware of the castellated ring and what it's for. Mine is loose because the guy who replaced the bearings didn't know what it was for (a GS specialist) and didn't ensure it was banged on tight when he reassembled the box.

[PhillyScott]

Thanks for all replies. My Rockster is a non-ABS version and the speedometer does sometimes flicker. I did remove the pick up block and inspected that, but did not look in to the final drive, so will do that and see if there is a loose castellated ring that needs to be pushed back in the hub.

Thanks again!

_Scott

[PhillyScott]

Hmm OK, I looked at the final drive after removing the pick up block and the castellated ring seems to be in place, affixed to the hub and rotates with the hub when I spin the wheel. Should the crenels (openings) on the castellated ring be somewhat off centre (left & right) of the magnet in the pick up block once it's inserted in it's proper place? Also, how much should the magnet protrude out of the rubber bit on the pick up block?

Thanks,
_Scott

[riceburner]

Hmm OK, I looked at the final drive after removing the pick up block and the castellated ring seems to be in place, affixed to the hub and rotates with the hub when I spin the wheel. Should the crenels (openings) on the castellated ring be somewhat off centre (left & right) of the magnet in the pick up block once it's inserted in it's proper place? Also, how much should the magnet protrude out of the rubber bit on the pick up block?

Thanks,
_Scott

The ring should be in a situation where you can't really see the main part - if you can see more than about 1/8" of the main body of the ring then it's probably just resting on the hub. stick your finger in and see if the ring is actually gripping the hub or not. The ring WILL rotate with the hub at low speeds - but over 1-2mph of rotation it won't (the oil drag on the bottom half will hold it still).


here's a pic I took last night - you can see one half of a castellation.

When the ring is pushed on with a screwdriver there is only a VERY LITTLE grip, so a finger WILL dislodge it (so be careful checking it after you've gone through the motions of levering it back onto the hub).

The magnet I think protrudes a small amount (1 or 2 mm). But it won't have shifted, it's solid in the block IIRC.

[PhillyScott]

riceburner,

Thanks for the info and photo!

Unfortunately, the castellated ring inside the final drive of my Rockster appears to be in the exact position as in the picture you published! So I'll have to continue searching where the problem might be located!

Thanks,
_Scott

[riceburner]

riceburner,

Thanks for the info and photo!

Unfortunately, the castellated ring inside the final drive of my Rockster appears to be in the exact position as in the picture you published! So I'll have to continue searching where the problem might be located!

Thanks,
_Scott

Can you move it with your finger?

[PhillyScott]

riceburner,

Thanks for the info and photo!

Unfortunately, the castellated ring inside the final drive of my Rockster appears to be in the exact position as in the picture you published! So I'll have to continue searching where the problem might be located!

Thanks,
_Scott

Can you move it with your finger?

No, not at all.

_Scott

[riceburner]

riceburner,

Thanks for the info and photo!

Unfortunately, the castellated ring inside the final drive of my Rockster appears to be in the exact position as in the picture you published! So I'll have to continue searching where the problem might be located!

Thanks,
_Scott

Can you move it with your finger?

No, not at all.

_Scott

hmm.

ok.

Next check - the line from the speedo pick up goes into the fuse box under the rider's seat. Do you have anything resting on that line? I did once, (a disc-lock) and it caused a loose connection.

[PhillyScott]

Unfortunately the line looks OK and nothing is resting on it.

_Scott

[riceburner]

Unfortunately the line looks OK and nothing is resting on it.

_Scott

hmm - beginning to sound like a broken wire somewhere else then.

[PhillyScott]

Unfortunately the line looks OK and nothing is resting on it.

_Scott

hmm - beginning to sound like a broken wire somewhere else then.

Yeah, that's what I'm thinking!

_Scott