Download Ulysses software from play store and turn on you location. Then go to clear sky and let the app get locked on gps satellites then put mobile in you pocket and start riding. Then drive with increments of 10kmph for a minute at least as speed is updated a bit slow in app as opposed to your meter.
Like run at 50kmph (do not exceed it) speed shown by your bike meter for at least one minute then check Ulysses it will show the top speed attained if both matched then your speedo is showing correct readings for that speed range.
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