Hi all. Just installed an aftermarket speedometer since my old one was shot. Got it all wired up and everything was great....... warmed up the bike gave it a few revs and noticed my speedometer moves like im riding it!! This doesnt happen every rev just every other or so and itll go up to the 30 or 40 mph range then drop when the throttle is released. I havent been able to ride it yet due to five plus feel of snow and dont have a lift.... is this a ground issue or???? Any help would be great. This is a 1999 custom chopper soft tail turned hard with an evo 1340. Any and all ideas would be much appreciated! Also the speedometer so everyone knows is brand spanking new from bikerschoice

 

Does it have a rpm function? If so does it read zero when the bike is running? Might have a wire crossed.

 

The speedometer doesnt have a tach "rpm function" this might sound stupid but does the harley speed sensor have a tach ouput to read rpms? I have a three wire sensor. Red black and white is the wire color codes for the sensor wires. According to the speedometer wiring diagram I have it connected properly but you never know with aftermarket gauges. Im not sure if a ground issue would cause this to happen or not?

 

its an issue with the servo in the speedo it is losing power so it wont hold where its suppose to. its probably one of these three things you wired it wrong or a loose wire or bad speedo ive installed hundreds of these aftermarket speedometers and only a handful worked with no problems the first time vdo and koso have been the easiest for me to install