speedo no work no more

[mtotrainer]

Can anyone give me some pointers as to why a speedo would quit working suddenly.All I did was take off fast in first gear and let it rev to red line and the needle just dropped,and it's not registering miles anymore either.Any help would be great.thanks...Jamie

[mrich12000]

My bike did that in the cold I found out the sender unit had a little bit of contamination on it. use a allan metric key remove the sender unit from the diff cleen the tip where u see the magnet reinstall. Also check the connector for any green stuff and they over the years do corroed.:thumb

[mrich12000]

Jamie jus saw your in oshawa email me and I will come over to do the fix for ya Michael ...mrich120@sympatico.ca :thumb

[mrich12000]

:thumb

[deilenberger]

Can anyone give me some pointers as to why a speedo would quit working suddenly.All I did was take off fast in first gear and let it rev to red line and the needle just dropped,and it's not registering miles anymore either.Any help would be great.thanks...JamieJamie - some hint as to year/model might be useful..

[bikerfish1100]

they all do that (sooner or later). or not.

[BuddingGeezer]

I once saw on the internet a guy that had strapped a GPS on the face of his K bike speedometer. True speed and cheaper.

Ralph Sims

[cjack]

Can anyone give me some pointers as to why a speedo would quit working suddenly.All I did was take off fast in first gear and let it rev to red line and the needle just dropped,and it's not registering miles anymore either.Any help would be great.thanks...Jamie

Most commonly, the three pins from the speedo unit to the circuit board would get tarnished and quit conducting. The best fix for that was to wire around them. Also the 4 pins from the speedo amplifier board to the circuit board (this is all inside the speedo) would also get tarnished. Same fix.
Sometimes the ring in the bevel gear would fall off the crown gear...usually you would see some jumping of the speedo if that happened. Also the two wires from the magnetic pickup in the bevel would become severed or the connector dirty...or the pickup coil open up. Not very common. You can test to see if everything works from the pickup to the speedo by removing the speedo and holding a turned on soldering iron near it. The speedo should read 45 MPH with the ign key turned on. If it does, then look inside the bevel and see that the toothed ring has fallen off. The soldering iron (or any 60Hz signal near the pickup) can be a signal so that you can check the connection up to the speedo and at the speedo pod itself. If you find none of that helpful, then open up the speedo pod and start jumpering the 3 pins...and maybe the 4 pins if it happens again.

There is another test you can do first...just thought of it...see if the turnsignals still cancel. If they do, then everything up to the speedo including the amplifier board inside it is still working. Just the 3 pins of the speedo itself are probably the issue. If you have no turnsignal cancel, then I would start at the bevel and the pickup first.

[mtotrainer]

thanks jack...looks like I'm going to be busy for a while,but with the radar loving police we have ,a working speedometer is a must.
;)

[mtotrainer]

sorry about that Don...You make a good point.My broken bike is a 1985 K100RT thx Jamie