Markg1 wrote: I don't disagree with the reliablity of air cooled engines. I was defending my statement that air cooled engines are outdated. All engines are inefficient. Only 15% of the energy form the fuel you put in your tank gets used to move your car. The rest is lost in heat and various other variables. Engines with higher efficiency have more energy leave as mechanical motion and less as waste heat. It is also more difficult for air cooled engines to achieve low emissions. Who knows, Harley might have no other choice but to go water cooled! Oh no! Can you imagine that. A Vrod engine that produces 125bhp and over 85 ft pounds of torque (which is really fuel efficient) moving a road king! It's okay guys, technolgy is not all bad. As far as those over 100 degrees days of stop and go driving, I think my water cooled Harley will run as cool as it's name!
The interesting thing is that everything is not as cut a dried as you would think. I lifted the fuel mileage specs for both the V-Rod (one of my favorite bikes), and the Road King - a bike that weighs significantly more than the V-Rod with an air cooled engine from motorcyclistonline.com. While the V-Rod would likely face a heavier throttle hand in any testing, this goes to show just how efficient an air cooled Harley engine is when compared to a modern liquid cooled design.
2010 V-Rod
CAN Liters Per Kilometer (City)
6.9
CAN Liters Per Kilometer (Hwy)
5.6
US Miles Per Gallon (City)
34
US Miles Per Gallon (Hwy)
2011 Road King
CAN Liters Per Kilometer (City)
6.7
CAN Liters Per Kilometer (Hwy)
4.4
US Miles Per Gallon (City)
35
US Miles Per Gallon (Hwy)
54
Measuring fuel mileage is easy and from the info above you get to really understand that all is not as it theoretically should be. The air cooled "outdated" engine is actually more efficient at moving a significantly heavier motorcycle than the more modern liquid cooled V-Rod. My experience riding air cooled Harleys matches this. They are one of the more fuel efficient bikes that I have ever ridden, even though they are heavy....and in some eyes outdated.