Originally Posted by EPMD
The shop I go to is very honest and they seem to know their sh*t. He was telling me it is an ethanol issue where it is absorbed by the tank plastic causing expansion, swelling and eventually the cracking. It is affecting primarily US and Canadian bikes. Ducati is also badly affected he tells me - worse than BMW. He is on his third tank.
The good news is that it is purely a cosmetic issue and apparently no one has had a failure leading to leaking gasoline. Most likely if that were to start happening BMW would be recalling the tanks. How the swelling and cracking only affects the outer cosmetic wall of the tank I have no idea.
The bad news is that BMW won't likely be changing the tank and any replacement tank is the same part number, same problem. The switch will "buy you a couple years" I'm told.
Oh well! I'll take a new tank soon hopefully and live with some cracks when they recur.
Well... In that case they don't know $h!^..... as there are no contact between the liquids, and the outer shell. Granted.... the gasses will permeate through, which is why you don't put stickers on any composite tank, but..... Ethanol does nothing to the poly ...... Tanks.