Originally Posted by Taelan28
What happens? Does the plastic crack? Does it rust inside? Serious question.
The basic problem (yes, it is a serious problem) is that Ducati and a few other manufacturers decided that a plastic paintable fuel tank would be a good idea. The polymer which was chosen by the supplier (Acerbis) is PA6, and is 'raw' on the inside meaning that there is no internal coating. In nearly every sales market, liquid gasoline fuels have had ethanol as part of their content for over 15 years. The problem with the PA6 as a fuel tank material is that ethanol absorbs humidity (water) which is then heavier than gasoline and drops to the bottom of the tank (does not evaporate out as it would if it were on top). The water is then ABSORBED into the PA6 and the tank proceeds to expand.
Keep in mind that Ducati, and its supplier Acerbis had been making gas tanks for every global market and should have been fully knowledgable about gasoline content in these respective markets. Due diligence and proper certification would have brought the concern to light during any general R&D process.
The tank deformation affected 50,000 US Ducati motorcycles including Sport Classics, 848s, the entire S2R and S4R Monster line, Streetfighters, to name an incomplete list. The tanks could leak out the back near the fuel pump assembly onto the top of the engine. The tanks could also deform and raise the tank off the frame which was designed to support the tank. There was never an NHTSA recall formally issued despite this being a fuel related (and safety) concern.
Ducati chose to indirectly deal with the problem, relying on word of mouth and internet 'awareness'. The affected tanks were replaced through a dealer reviewing them, a local rep approving the replacement and generally all being quiet. The replacements were also manufactured of PA6, the same material as the deforming tanks. Some customers have had to get their tanks replaced 2 or 3 times.
There was a formal lawsuit brought against Ducati NA, where the settlement was to replace tanks if deemed necessary, as well as modifications to the bike. These included limiting steering angle (increasing steering stops), adding a bracket to the tank itself (which would be visible), supplying an alternate seat (shorter if the tank was growing lengthwise) etc. In other words, Ducati was attending to the situation by changing everything BUT the gas tank and the faulty polymer.
Many owners of these Ducatis have been extremely soured by the situation. Even enthusiasts and long time Duc owners ask WTF.
To be fair, KTM, Triumph and Harley Davidson all had similar problems due to PA6 paintable fuel tanksmade by Acerbis (the supplier for all of these). I believe at this point, Acerbis is no longer.
So, how's that for 'European engineering prowess'?