Cornfed Cruiser

Image Gallery [1] Net Doyle explains the Harley's cold-start system.

Here's how one of MOTHER's alcohol fuel seminar instructors turned his Harley-Davidson motorcycle into a ...

When one balances the "convenience" of owning an automobile against today's high fuel prices and—in urban areas—limited available parking, it's easy to see why many people have chosen motorcycles as personal transportation. Of course, the two-wheelers do have their disadvantages (especially in poor weather), but as far as MOTHER's alcohol researcher and seminar instructor Ned Doyle is concerned, a "scooter" is the answer to the gasoline crunch.

Quite naturally, then, between a desire to broaden his range of alcohol fuel experience and the chance to hit MOM up for free ethanol during the course of a yearlong testing period, Doyle went ahead and converted his 1979 Harley-Davidson Sportster to the renewable fuel, and the results were, in a word, amazing. The aircooled, 61-cubic-inch engine—normally well endowed with both power and vibration as a result of its long-stroke, twin-cylinder design—immediately became more "civilized" . . . while apparently delivering greater amounts of torque (Doyle attributes this to the density of the alcohol fuel charge and its slow-burning nature, which evenly distributes pressure on the piston head). The only noticeable "trade-off" was a slight reduction in top speed and a 7.8% decrease in mileage . . . both of which the seminar instructor was content to swap for a smoother, more comfortable ride.

Two other areas that showed marked improvement as a result of burning the homegrown fuel were engine temperature and oil consumption. Because ethanol has a high latent heat of vaporization (as compared with that of gasoline), it absorbs a good deal more warmth from the engine's manifold and cylinder heads—in the process of changing from a liquid to a vapor state—than does its more conventional fuel counterpart. The result is a reduced engine operating temperature . . . a welcome bonus which—especially in an air-cooled powerplant—can result in longer periods between oil changes.