I added a tooth to my W650 front sprocket to correct the speedometer/odometer. The instrument's sensor is in the front sprocket area.
Vince @ SWFL or WNC 2001 Kawasaki W650
2012 Dong Fang DF250RTB hard tail bobber
2014 Sky Team ST125-8A Z50 clone monkey bike
2014 Ice Bear PBZ110-1P Z50 clone monkey sidecar
2014 Sky Team MC-D34 CT70 clone