Have you ever driven a bike on plain highway?

There is a plain and empty highway without any obstacle and holes , a cleaver mechanic John starts his bike journey on the road with a modified bike . After some time he founds that his speedometer shows 40 km/hr. reading.At that moment he lockes his accelerator and goes some distance on highway . After some time again he looks at his speedometer and founds the reading to be ..........

Note: John doesn't do any movement of accelerator after the locking.