Speed I have bajaj Wave 9 months old. When I take my hand off the accelarator

Bike's speed goes down drastically.Even though I am on the speed of 50 to 60 in 4rth gear this happenes that the moment I leave the accelaratorbike retards. Is it sth with gear system?Yep thats engine braking for you. Try the same with clutch in and you should experience no retardation. No you can't nullify it, all engines have it and its nothing to do with fuel quality. When you take your hand of the throttle the engine stops sucking in fuel but the cylinders keep going up and down and compressing the air inside them. This takes work and hence slows you down. In any case your looking at it all wrong, its a good thing not a bad thing. It helps you to control your speed going down hills and stops your brakes from wearing out so quickly. The higher the gear your in the less engine braking you will have, but applying bursts of throttle and then trying to coast is still not a good way to ride. Just use the throttle to control your speed, thats what its there for.,,,