We all know that drinking and riding is a very bad idea, but today's subject is what happens when you put alcohol in your bike.

Oxygenated gasoline (including ethanol blend) has a lower energy output per volume and thus leans out the air-fuel mixture, especially on carbureted engines. Because most motorcycles already run lean at low RPM due to emissions standards, this can worsen the hesitation that many bikes suffer at low RPM. Ethanol is also more volatile than gasoline, making the vehicle more prone to vapor lock unless the volatility of the gasoline itself is reduced, which then reduces startability and performance.

Another main concern with using ethanol-blended gasoline is the potential for what is called "phase separation" in gasoline that contains ethanol. Phase separation occurs when enough water contaminates the gasoline, causing the ethanol to attach itself to the water molecules, leaving two distinct layers in the storage tank: a gasoline-only layer at the top and an ethanol/water "cocktail" along the bottom.

As noted on Chevron's Web site, while conventional gasoline can dissolve up to 150 parts per million of water at 70°F, 10% ethanol gasoline can dissolve up to 7,000 ppm of water at 70°F. The lower the temperature, the lower the water tolerance - when this blend is cooled, both the water and some of the ethanol become insoluble. The result is two layers of liquid — an upper gasoline layer and a lower ethanol-water layer. Because ethanol is very high octane, once the ethanol separates the remaining gasoline fuel is low octane and may cause knocking in an engine, while the engine will not run at all on the lower ethanol/water layer. If you switch to reserve and your bike dies, you now know why.

Ethanol blends are hygroscopic, meaning they absorb moisture from the air, raising the potential for phase separation during storage if the tank is vented to the atmosphere, and is subject to condensation formation as a result of temperature change. Fuel system metal components can rust or corrode in the presence of water.

Also of major concern: how does ethanol blend perform with pre-mixing in machines such as chain saws, outboards and dirt bikes?

Bottom line is: Ethanol blended gasoline is more expensive, has worse performance characteristics, and is a horrible choice for winter storage. The demand for corn due to ethanol production also raises food prices, which hurts everyone except corn farmers.

One solution for winter storage would be to completely drain the tank and fog it with oil to prevent rusting, but this is both inconvenient and risky since a tank not attached to a motorcycle is more prone to being damaged. Another solution would be to spend $7 per gallon and put in ethanol-free racing fuel, but many motorcycles, especially those with catalytic converters, cannot use most racing fuel blends due to lead or other metals.

Tackling this problem with one or two bikes is enough of a challenge: when you have 25 training bikes, it makes life even more fun.