I mostly ride my motorcycle on long trips distances of 200-250km with an average 100-120km/h speeds and using almost exclusively premium gasoline. My motorcycle is a Yamaha Fazer which does not REQUIRE premium gas but it has a somewhat "sportier orientation" motor. In Greece this is marketed as 100octane fuel but its well known in many cases to be a normal 95oct gasoline with additives that raise the octanes (maybe up to 97-98???)
The cost difference between normal grade and premium grade fuel in my country is about 12% (example prices 1,64E/lt for plain and 1,84E/lt for premium) I have been told in many occasions that it is more cost efficient to use premium gas while traveling but after a couple of trips with plain fuel i can only notice a slight difference (increase) in consumption.
I understand how hard it is to make an accurate assumption while so many factors can be involved but i tried the same route (Patras-Athens 220km) carrying the same equipment filling from the same gas station and successfully tried to maintain my RPM on 5.5K throughout both trips. While on plain i got a 5.25lt/100km and while on premium a 5.05lt/100km which (given the above prices) translates to 8.61E/100km for plain and 9.29E/100km for premium. So still i cannot see any actual cost saving in using premium gas. Am i missing something here? Is there ANY occasion where using premium would actually prove to be more cost efficient???