Grand Prix 250
Main Motorcycle: 2006 Tiger 955i
Join Date: Jul 2018
Location: Bourne, UK
Other Motorcycle: Honda CB-1 (CB400f)
Most (if not all) plastic tanks suffer similar issues. its down to the Ethanol they put in fuel. Many years ago my Aprilia RSV tank was fine, until Ethanol was introduced in UK fuel. then the tank started to warp (as did my girlfriends Ducati Monster tank).
Fast forward to last year. My Tiger tank had the dreaded bubbles under the decals. My research suggested it was the Ethanol causing the problem. There is also evidence that it can also warp the tanks. If taken off the bike & left for a while, the bolt holes don't align the same as when it was taken off.
Since I got my Tiger last year, I've pricked the decals & 'massaged' the air out. I also only use premium fuel (BP or Shell) which until recently didn't contain Ethanol, at least in my geographical area. No returning bubbles.
Sadly, over the last 3 - 4 months, BP have started adding ethanol to their premium fuel. Bubbles are now back.
Ethanol hates plastic!
If you have a particular faith or religion, that is good. But you can survive without it.
No matter how smart you are you can never convince someone stupid that they are stupid.