It's not fresh news that Brazil had one of the most sucessful experiences with ethanol as a substitutive for gasoline since the 70s when mandatory blends started to be enforced nationwide, and since '79 there were dedicated-ethanol cars, with flexfuel ones starting to come in 2003, but it only started to become more popular among motorcycle users in recent years, since they were already seen as an alternative to get lower fuel bills. Air-cooling, altough turning the thermal management quite harder while using alcohol-based fuels, is still prevalent in entry-level bikes such as the Honda CG 150, the local market leader.
Unlike regular flexfuel and the older ethanol-dedicated cars, which used to include an auxiliary tank for gasoline to ensure cold-start ability, a feature that is getting outdated due to pre-heated fuel injector units increasing popularity, it was never available in the flexfuel motorcycles because of the space availability which is more critical. However, since pre-heating of the injector tips increases significantly the electrical loads and the cost of a brand-new motorcycle, when Honda started to offer flexfuel versions of the Honda CG in 2009, world's first commercially-available flexfuel motorycles, they were initially labelled "Mix" instead of Flex, since some gasoline blend was recommended to ensure an easy start-up in colder days...
The introduction of electronic fuel injection was deemed extremely important to make it viable, due to the real-time adaptability to the fuel blends, and alongside the introduction of a catalytic converter it decreased significantly the emission levels, which had been a matter of arguments since its enforcement had been milder for motorcycles than for automobiles, despite the proportionally-greater increasement in motorcycle sales.
The same feature quickly became also available for the Honda NXR 150 Bros dual-purpose motorcycle, giving it another strong sales argument.
Flexfuel ability was also introduced to other models, such as the Honda CB 300R and the Honda XRE 300. Altough not being high-end motorcycles, they're actually a step closer to show the viability in other segments which could eventually justify the increasing cost of improvements in this feature, such as direct injection which would offer advantages regarding thermal management. Their all-around performance is also more suitable to eventual road traffic than the CG 150 and NXR 150.
There is still no water-cooled flexfuel motorcycle commercially available, altough that would improve the thermal management significantly. Another critical aspect with the current generation of flexfuel motorcycles is the usage of pressed-steel fuel tanks, more sensible to the ethanol corrosive effect than plastic-moulded tanks currently widespread in cars. But, as a trend which started just recently, it's already proven as an economically-viable alternative to decrease the usage of petroleum-based fuels...
