Mine makes vibration at 4th gear when accelerating in certain rews. It's like roar roar roar... It has been always like that. Quite annoying and trying to avoid that using other gears more. Couple days ago i lifted the bike and let it run at idle wheel spinning in every gear. When i change to fourth, the noise was embarrassing. It is also in other gears, but from 3rd to 4th is was big difference.
Has anyone lifted the bike and tried? Does your bike make such a noise? While driving it doesn't make raddling like that. Could it come from drive shaft? Is that normal? It sounds like coming from front end of it.