The rear view of a motor bike starts vibrating violently at a particular speed of the motor bike.WHY??????????

Answer 1

If you want to get rid of this annoying resonant vibration, load your rear view mirror's shaft with something heavy. (Clamp something onto it, or even wind a large quantity of tape around it) so that it will now vibrate at a lower speed. (A speed that you are mostly likely to exceed all the time)

Answer 2

This has to do with something called resonance. The vibrations coming from the engine of the bike at a certain speed put pressure on the shocks of the bike. The vibration hits the shock at just the right time in the shock's vibration sequence to make the shock begin to bounce higher and higher. This causes the violent vibrations in the bike. A similar example is when you are driving a car over a washboarded road--the ripples in the road match exactly with the bouncing shock at a certain speed, and the front end of the car begins to bounce up and down rapidly. Hope this answers you question!!

Answer 3

Generally when a motorbike moves, all the body parts vibrate at different frequencies respective to each. Not always but at a specific speed the engine and the other body parts of a motorbike vibrates at a constant frequency. At that time amplitude of the whole body increases constantly. When this state comes not only the rear view, but all the body parts vibrate. The compactly attached parts vibrates less and the rear view as it is not compactly attached to a bike, it vibrates violently.

Answer 4

If you observed that, then congratulations, because you just demonstrated RESONANCE.
Resonance is the phenomenon by which a body when subjected to forced vibrations, picks up these vibrations and begins to vibrate with an increased amplitude.
Let us say, your bike was subject to vibrations from the engine. But as you keep turning the accelrator, the frequency of vibrations start increasing. When this frequency matches with the natural frequency of the bike, it picks up the vibrations and begins to vibrate at an increased amplitude.

Answer 5

Everyone behind you has started to shake as you pass them at this particular speed...well actually I think some of the above answers have been more scientific.

Answer 6

i think moleman_992 might be correct.
Maybe u can tune your shock to make it stiffer, so that the vibration will occur at a much higher speed which u will not go into.

Answer 7

Probably the wheel bearings or shock absorber bushes are gone. Ask your mechanic to check those.

Answer 8

whats ur bike make/?
sure it will be a lower model