I wanted a convenient and safe method to attach my mobile phone to my scooter, so that I can see who's calling my bluetooth earphone, see GPS guidance etc. Of coarse, you should NEVER operate your mobile phone while riding!

Step 1: I Bought a Simple Cheap Holder for Around 8$

Then cut the upper part of it, using a knife and a hammer to knock it (without the hammer it would take me hours).

Step 2: Measure and Mark the Exact Point of the Screws

In my scooter model (Piaggio Xevo) the plastic cover of the handlebar is convex, so I had to be accurate.
Drill 3 holes (this is the optimal number for strength and stability, you can drill less or more if you want).
Then drill the upper part with a wider drill, so the screw head will be all covered. You might need to grind the screw head so the profile will be flat.

Step 3:

Dissemble the plastic cover of the handlebar. Mark the exact point and drill in it. You may want to drill with a narrow drill first, and only then widen it - this will lead to more accurate results.

Step 4: Cut an Old Bicycle Tube

Cut to shape 3 rubber pads. You can cut more or less as this will affect the tightening - more pads will allow stronger tightening.
Assemble the whole pieces according to this order:
- Plastic clip
- 3 Rubber pads
- Handlebar cover
- washer
- Nut

Tighten it all and...

Step 5: Have Fun!

During the firsts few rides my recommendation is to secure your mobile phone with a cord, just in case anything goes wrong... After 2-3 hours of riding check the tightness of the bolts and tighten if necessary.

Drive safe!