My ex-bike was a Yamaha FJR1300 and 45 MPG is about the average you find on FJR1300 messages boards similar to this one. MPG on a punched out Harley will be a lot less since cruising range is not a big concern. An FJR1300 is designed for long distance touring so cruising range is something people look at. In regards to horsepower, even 600cc sport bikes easily break 100HP these days, mostly by revving to 15,000+ RPM. I believe Yamaha's R1 has 180HP.
While it's true that emissions regulations are less stringent for motorcycles, many street motorcycles these days, especially sport bikes, have catalytic converters and oxygen sensors. After my old bike warmed up, I didn't smell any exhaust fumes. I'll agree that bikes probably won't pass SULEV standards though. My guess is that most sport bikes are sold in Europe and are designed to meet more stringent European standards.
Custom choppers and a lot of Harleys seem to use carburetors. Since a carb can't control the fuel/air mixture well enough, cats probably are not an option. A lot of the choppers have nothing but a short pipe between the exhaust port and the atmosphere. I'd bet that these bikes are more that 20x more polluting than a Hummer. Times are changing and some cruisers are now fuel injected and have catalytic converters. That said, whenever I'm behind a cruiser, I set the ventilation system to recirculate.
Anyway, enough motorcycle talk for me! I'm still mourning my loss just a little bit
and need to focus on my goal of 50+ MPG from my next tank of gas!
Sold motorcycle, bought a HCH
1003 miles a tank personal record. 74MPG calculated. HCH1 CVT
