The petrol flap on these models is secured at the hinge by a length of brass tubing. This is simply inserted inside the hinge rolls & peened over on the ends to hold it in place. To remove it, the simplest way is to use a Dremel with drill attachment and gently drill away the crimped over edge toward the rear of the machine, pointed out at the end of my driver in this pic.
Sunday, August 23, 2020
You should then be able to use a nail or other metal object to push the tube toward the front of the scooter a little, enough to grab it with pointed pliers. Now twist and pull on the tube whilst lifting and closing the flap. This sometimes helps it work loose.
Notice the original Petrol Advice sticker still in position, on the underside of the petrol flap.