I've noticed that all of my bikes have shown mileage improvements this summer- most on the order of about two miles per gallon. Over the last 13 years my '98 Superhawk has delivered a consistent 37 MPG- until this year. Three fill-ups ago it climbed to 39 MPG, two fill-ups ago it went to 42+ MPG, and on my last fill up it returned 43.67 MPG. NO mechanical changes like valve adjustment, carb synch, low restriction K&N or BMC, fresh plugs, lower viscosity oil,taller gearing, or higher tire pressures. I've been using Shell's "Nitrogen Enhanced" 86 octane fuel and it's the only difference. Normally I'd call BS on any marketing claim but I now have my doubts. Anybody else runnin' Shell and seein' a MPG bump this summer?

 

Do an Internet search on top tier gasoline. I had the same results years ago. I noticed that I could go 10-15 more miles before the low fuel light would come on when I had filled up with Shell. I noticed my Astro van would average about about 2 mpg better. A few years ago I was on the SV forum and someone gave the explanation. Several years ago the auto industry approached the oil companys and asked them to formulate a fuel to help them meet their economy and emission standards.Shell was one of the companys that complied with their request.

 

Actually Top Tier refers to those companies who voluntarily add more than the government mandated cleaning agents to their fuels. BMW, Toyota, and others pushed for higher levels of detergent because our relatively high sulphur fuels were causing problems in their vehicles. I've used Shell for years and this years recent "Nitrogen Enhanced" Shell is the first MPG increase I've ever seen. Perhaps it's the locally mandated EPA formulation but I've only noticed the better mileage since the "summer" blend was reintroduced after the cold season.