Modern Vespa

Looking for some suggestions on a vibration issue. No vibration noticeable below 40 MPH. Above 40 there is a vibration coming through the headset. It is very high frequency like a buzzing sort of vibration (hands feel numb sort of thing). The scoot is a P200 kitted with a Malosi 210 and 24mm Carb. The front end was rebuilt by me with all new bearings and a new adjustable performance shock. I am not sure if the vibration is coming from the engine or the front end.

I have adjusted the tire pressure up and down and doesn't seem to make a notable difference. Haven't messed the shock. I feel the frequency is related to the motor but have no experience to really make that statement. Could it be through the mounts?

Maybe this is just the way it is supposed to be and I don't know that. All my other scoots are pretty stock and don't do this.

Any and all thoughts and suggestions welcome.

What kind of motor mounts are you running? How old are they?

Is it directly related to speed, or RPM's? Does it occur regardless of gear once you get over 40mph?

Rapid vibration like that is usually motor. Does it kick in at ~40 MPH, regardless of gear, rather than at a certain RPM?

Brand new mounts came with the motor casings - Malossi. It may be there as I accelerate through the gears - just not noticeable to me. Once you are cruising you are sensing so much more so that is where I notice it and it is usually above 40 when I look at the speedo. I don't hold the RPM's long enough as I am changing up to notice. I guess I should do that. Good thought.

If it is the motor is that just it? Make sure I check all bolts more frequently

Most likely, ignition timing or jetting.
When the timing is around 18 degrees with the jetting rich enough, the vibrations will go away. And it will be faster too. Win win.

Just spitballing here: Does your scoot have leg shield trim? I recently put aftermarket plastic/metal trim on my smallstate and now it buzzes like a hornet over 35 mph. Took it off and the buzzing went away. Some kind of airflow resonant frequency thing, I guess.