Since the Evolution motors, with the aluminum cylinder instead of the cast iron ones, and into the Twin Cam motors, there is a perception of the motor running hot. This is due to the aluminum cylinder being a better conductor of heat, allowing the heat to transfer through the cylinder to the outside better than being more contained by a cast iron cylinder.
Also, the Twin cam runs hotter than any prior Harley motor. In fact, though originally scheduled to be released for the 1997 model year, it took them until a couple of years later to get the heat within an acceptable range. In fact, there was talk about installing an oil cooler from the factory, but that fell by the wayside.
Also, yes, due to EPA emission requirements, they tend to be set to run lean, which doesn't help.
I have a 2008 FLHRC, and at a long stop light, the rear split pipe cooks the inside of my right thigh.
Answers & Comments
Since the Evolution motors, with the aluminum cylinder instead of the cast iron ones, and into the Twin Cam motors, there is a perception of the motor running hot.
This is due to the aluminum cylinder being a better conductor of heat, allowing the heat to transfer through the cylinder to the outside better than being more contained by a cast iron cylinder.
Also, the Twin cam runs hotter than any prior Harley motor.
In fact, though originally scheduled to be released for the 1997 model year, it took them until a couple of years later to get the heat within an acceptable range.
In fact, there was talk about installing an oil cooler from the factory, but that fell by the wayside.
Also, yes, due to EPA emission requirements, they tend to be set to run lean, which doesn't help.
I have a 2008 FLHRC, and at a long stop light, the rear split pipe cooks the inside of my right thigh.