Vibration 50 Special ? HELP

Hi folks.

As a fairly new comer to scootering, my technical knowledge is zero.

So wondered if anyone could help ?

I recently had to change the kick start peddle. Which involves moving cables clear, temporarily.

Plus, I replaced the exhaust. And manifold head gasket.

I am now getting REALLY bad vibration. And extremely noisy revving. Even in neutral. But not on initial start up.

And at anything above 35 mph, it develops into a  high pitched scream. ( Even when practically 'free wheeling' down a steep hill, with no throttle. )

Clearly something is desperately wrong. 

It has a 110 kit fitted.

Any help in pointing me in the cause, and cure. VERY much appreciated.

Thanks for reading this.

Jeff.