NightWing wrote:
I believe that tight screws do play a part, in that the plastic is under duress at that point, so the spilled fuel will have a greater effect there, especially if there is already a crack.
Do all you can to avoid sloshing fuel down the ass end of your scooter.
Interesting! I've spilled gas over my tank a few times, and have noticed some minor cracking around my rear lights. Now I know why!