If I use very light throttle at low speeds - especially pulling up a grade from a stop - there is some shaking in the drive train (weights, belt, clutch ??)
If I remember to use just a bit heavier throttle when pulling away - there is no shaking. ( I am freq. impressed that this 163cc's does so well with a quarter ton of weight to get rolling!)
But, please do answer Vivo's question to receive a good explanation of the causes of your shaking.
Stig