Chopper Forums

Warm It Up Before You Ride Off (from the Chicago H-D newsletter)

Warming up before you exercise makes it easier and less stressful on your body. Warming up your bike before you take off does the same for the machine. Here's why. Except for the V-Rod, Harley's engines are air-cooled. Air-cooled engines operate over a wider temperature range than liquid-cooled power plants. That means things inside an air-cooled engine will expand as they warm up and contract when they cool down. Because the metals in the engine are dissimilar, they have different expansion and contraction characteristics. That's why it's so important to use a high-quality multi-viscosity lubricant. It's more important, in fact, than the quality of oil you use in your water-cooled automobile. Putting stress on a warmed-up engine seldom causes problems unless, of course, you overdo it. However, stressing a cold engine can and often does create problems. No, the stresses don't cause immediate problems, but they can over time. So why aren't all Harley engines liquid-cooled? Two simple words: complexity and weight; a lot of complexity and a lot of weight. Create a liquid-cooled engine and you'll need a radiator, water jacket, water pump and expansion tank, to name just a few major components. We're confident that the problems of weight and complexity will be overcome in time. However, for now we would strongly urge you to let your bike idle for just a few minutes before you twist the grip and let out the clutch, even if you have a liquid-cooled bike.