Figuring out how much gasoline a motorcycle will use before we buy it can be quite difficult. Because I’m a regular guy I’m going to try and explain it in my everyman terms. In regular POWER:WEIGHT calculations POWER refers to horsepower and WEIGHT (obviously) to the weight of the machine. By plugging in our motorcycle’s numbers on a chart we get a dependable numerical outcome (that usually only means something to an engineer). But there is no mathematical equation combining POWER (or displacement) and WEIGHT that can predict its MPG. Case in point: a 1200cc 4-cylinder VMax weighing 600lbs with 150hp gets about 35mpg. One might assume that by halfing the engine numbers you’d get double the mileage, that a 650cc 2-cylinder Yamaha V Star at a quarter of the hp should get at least 70mpg! And again, a 250cc Suzuki TU at 20hp should get about 140mpg. Right? Wrong. The V Star gets about 50mpg and the TU about 80mpg. Ok, less than we thought, but the rise in mpg still seems to be about 40% for each time we half the displacement, isn’t that some sort of an equation? With this rule we’d therefore expect a 125cc single-cylinder Honda to get 120mpg. But wrong again, Honda makes a 125cc single-cylinder motorcycle with 8hp (sold only in Asia naturally) that does 60mph and gets 150mpg! I know because I own one. (It also only cost me $1,000 new, but thats another issue.) So there’s an all-too-frequent anomaly that makes us ask, um, why? Basically it’s about engineering. At one end of the scale you have the manufacturers that have barely upgraded their century-old underpowered overweight designs (Harley, Enfield, Triumph) and guzzle gas like there’s no tomale...and at the other end you have rocket scientists like Honda who tweak their motors annually to maximize performance and efficiency. One end is agricultural, the other state of the art. How else could open class races be won by 125cc Japanese bikes when you have monster European and American liter bikes that should by all appearances take home the trophy? How else could you drive your Honda Cub for 200 miles on a gallon of gas? How else could you ride your old Kawa Z900 for 100,000 miles with barely more than oil change for maintenance. How else could you crank your 80cc saki-cycle to 139mph on the Bonneville Flats? Hmmm. Engineering. Manufacturers in Asia know that most of their customers buy their machines for utilitarian purposes and operate on a household budget in countries where oil is not subsidized, and furthermore those customers want to ride those bikes for 20 years and pass them on to their children. Mechanical excellence is the goal or they simply wouldn’t sell. The customer’s always right, remember. So “is it a conspiracy?” you ask. Only in that we are not told by manufacturers about what is not available to us, and we are too ignorant to create the demand. We need to get self-informed about what’s available technologically (as we do with phones and other gadgets) and once we do get smart and start demanding they will produce for us too. Oh, and we have to discard this ridiculous “bigger is better” notion or we’ll soon discover we really missed out on some amazing machines and spent way too much of our hard-earned salaries fueling antiquated ploughs.
