Modern Vespa

The known problem with opening the stuck tank door. This is the permanent and not complicated solution I implemented in .
I used two springs from a battery case from a junk children's toy. These were bolted to the left and right of the tank door lock. On the opposite side, on the inner surface of the door, I put (with double sided tape) two soft rubber pads for a better fit.
It works!

McGyver lives again, nice one mate, useful info

just adjust it you can bend it inwards or use a heatgun or hairblower

My cable is no long working with my tank cover and need a screwdriver to open it. Dealer quoted about €500.00 for labor and parts. Do you have some instructions on what you did? I am trying to think of something that doesn't require hacking anything up.

Mine wouldn't work either and I found the end of the cable had come out of the ferrule but I can't remember if it was the ignition lock end or the fuel tank end anyway it was an easy fix after taking all the plastic off it to check. But then again I am retired and have a lot of time to waste with my crosshead screwdriver.

My cable sticks. Can't turn the key at all to open the tank.

The gas lid won't open with the key turn release so I just pry open the lid with the ignition key itself. Quick and easy.

Answer to new200guy
The modification with springs works only if there are two situations A) MP3 model with CABLE from central lock key, not electrical gas door lock and B) The existing cable is still working, but the edge of the gas door is very close to the gas opening.
So,
if your cable is broken, the tooth (dent) of the lock, is still moving fοrward and backward with the help of internal spring.
All you need to do is to snare this tooth (dent) with a silk thread like a loop and lead this thread through a small hole into the helmet compartment under the seat, so you can unlock pulling it from the underseat compartment. In other words, you copy the system that cars have to open the fuel door from the luggage compartment in freezing weather.
With this trick, you save yourself all the trouble and expense of changing the cable (and there are a lot of them).