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Just got it firing!
As the owner of several bikes in the U.S. that have plastic tanks, including two Ducati and a V11, I'll add what I know about plastic tanks and ethanol. The plastic tanks on European motorcycles are made by Acerbis, an Italian plastics company. They are made from a type of plastic known as PA6 nylon. If you look inside your fuel tank, its a white plastic. The manufactures love it because it holds glossy paint so well and can be molded into complex shapes. If your bike has a painted plastic tank (not a shell, or cover) you can be certain it is PA6 nylon and (sooner or later) WILL be affected by ethanol in the fuel. The tanks are "roto-molded" meaning they pour liquid plastic into a mold, and then rotate it like a chicken on a rotisserie to coat the inside of the mold. Once again, shine a flashlight into your tank and you might see small drips and runs like candle wax, from this process. This can and does lead to varying wall thickness which explains the bubbles and blisters that appear. PA6 nylon is "hygroscopic" meaning it absorbs water. This is what leads to the expansion and deformation of the tanks over time. I think I read where PA6 nylon can absorb up to 10% water by volume. Every used Norge I've looked at shows some swelling, which can be seen by turning the handlebar to full lock, and the top triple clamp will come into contact with the tank before it hits the metal stop. There are usually two small chips in the paint at the front of the tank where this happens. Since the amount of moisture the plastic absorbs is limited, the swelling does stop. Your tank won't grow forever, like some tumor! But getting the mounting holes to line up after the tank has been removed for service can be a real pain sometimes. The manufactures have slowly phased out some (but not all) PA6 plastic tanks for a different material, black in color, which will not hold paint, hence the trend to fake plastic "covers" over the tank on many bikes. Hope this long-winded explanation sheds some light on the subject.
Great explanation to how and what is used to build these Acerbes tanks. BUT, I can tell you from experience, MV Agusta is using a new plastic, or maybe a coated plastic that has solved the issue (so far). I received a warranty tank from MV Agusta for my 2014 Rivale and the tanks look identical, inside an out..... both have that same "milky" looking plastic inside the tank. I was expecting something different, but nope! The only thing different was the new tank had a molded "E" on the back side of the tank, I suspect for "Ethanol" and that "E" had a gray circle around it. It's been 1.5 years since it was replaced and it still looks perfect. The original tank got blisters within a month of ownership. So, Acerbes definitely has a new material. Hopefully all the manufacturers start using this new plastic!
We're forced to run E10 here in Southern California, so to those that say they don't run E10 because of the issues described - congrats for having it available to yourself, we don't have that option and it sucks! I hear Europe is soon to receive E10. I feel sorry for you guys. Be prepared for headaches.