Speedo problem

[PeteH]

Speedo packed in a couple of weeks ago, checked out the magnet and that looks fine except for a hairline crack, drive locates in cut outs ok and theres voltage at the connector behind the cockpit.
Belled out the wiring from the back of the speedo to the same connector and all seems ok, with the engine running im getting 12v ish at each wire going to the sensor...is this right???
Cant seem to find a definative answer to checking it out propery, so im thinking of a second hand one, but if that doesnt work how do I know if its still the problem or a duff speedo??
Thanks in advance for any replies

[Bixxer Bob]

Pete, the sensor sends pulses so measuring the voltage isn't telling you anything.  You need a scope to see them.

I'm guessing the hairline crack is your problem as folks have tried unsuccessfully to repair broken magnets.  I've never had mine apart so I'm not exactly sure how they work but I'm guessing the magnet affects a sensor on each revolution. 

[Advwannabe]

Yep, busted pickup. Have you or your shop taken the front wheel off lately? It often happens at tire change time if care isn't taken with the sensor.

Expensive too, sadly.

[Chris Canning]

I had one pack up on me on my 885 with a couple of thousand miles on the clock,everytime I have the front wheel out I flush it out with a can of WD and brush and their's heaps of crap that come out of it.

[PeteH]

Ok, I think I may have found whats up with the speedo. Looks to be the sender unit itself as I`m getting a constant 5v on the Bl/W wire on the back of the speedo this should break when the magnet passes the sensor.

So, Is anyone in a position to check this theory, it will involve removal of the cockpit and have the enging running ? and be able to turn the front wheel by hand.

Cheers