Modern Vespa

Hi guys i have a new 400 hpe and my wife (short) is complaining about her position: the hand grips are far away, low and way in the back. My topcase arrives next week but i dont think that would help because once she rests her back i think her foot wont be be reaching the footpegs anymore Did anyone had the same problem?
Also the bike had a front vibration between 65-70km/h.
They checked it at Piaggion (Spain) and they said its not about wheel balancing, its because of the high windshield.
I dont believe it is other than wheel balancing because its specifically at that speed. I think they were too lazy (also Spain) to unmount the wheels and check them.
(They also installed heavier bar-ends, they said that it would help a bit)
Did anyone had to balance the wheels at some point?
Thanks!

Sounds to me that your wife and the MP3 are anatomically not compatible.

Motorbikes are like shoes and clothing. If it doesn't fit, it simply isn't meant to be.

Small scooter tires normally do not need wheel balancing. However do check for wheel and suspension damage or loose components. Particularly, make sure the wheel lug bolts are tightened evenly and tightened to spec in a criss cross pattern to distribute the clamping force.

On the MP3, I insert the lug bolts by hand until snug, followed by a 90 degree with the wrench. Then tighten to factory spec in the following pattern

passenger should always have their hands on the riders waist, not on some grab rails. this provides feedback to the passenger when the rider initiates a corner and they can move with the rider.

I balance the wheels ever time when installing new tires. have proven to many many folks over the yers just because the tire are 12" they require balancing as well as larger tires.

you can balance them your self, check out marc parnes wheel balancing tool. easy to use.

Thanks guys.
The thing is, the bike is new (factory 0 miles)
I suppose (and pray) that everything is in place and tightenned. I think they checked that too.
I will pass by the tyres shop nearby and have them balanced, maybe they'd put those beads for balancing.
Concerning my wife, i guess you all are right. I'll tell her to grab my waist and wear one of those:

Heck, if the bike is brand new with zero miles then just have Piaggio swap it out for another one.

You were sold a 3 legged dog that probably got made on a Friday before the summer vacation, so quality was probably below Piaggio's usual standards.

My wife really likes this belt with grab handles, which definitely make her a better passenger
Four handles give options
The slightly forward position, help the pegs feel better
The belt doubles as a kidney belt, which helps me on longer rides
https://www.amazon.com/dp/B01ITIH82M

URL edited to remove all the personal 'ref' crap - jim

EXCELLENT option. thanks for sharing

The used MP3 500 I purchased with under 200 miles on her had a similar vibration at modest speeds. A local bike shop balanced them (and seemed iffy about their success) to no avail. Put Ride-On sealant-balancer in all tires and now it's perfectly smooth. I called Ride-On and they recommended the Motorcycle version of their product, saying the Scooter version is for smaller bikes that are primarily used in urban conditions. I went with 7 oz. in each 13" front and 9 oz. in the 14" rear.
Hope this helps.

I CAD this peg and 3D print these for my wife , and it works great for her. She's 160cm (5ft3).

I can send you the CAD if you like.

I used to have issues at 65-75mph with vibration. Definitely wheel balancing issues in my case. I rebalance it with at least 200gr each wheel. Now it's also perfect.