just saved that picture, labeled it "where to put my hands at a stoplight this winter"....

 

I've heard that chrome holds heat in, which is why and "all chromed" engine is not advised. This was back when you could get chromed VW engine tins, and they were not recommended due to heat retention.

John

 

You are correct John Harper
Physics theory: Heat (electromagnetic energy) radiation rate, per unit of surface area, is proportional to the fourth power of the surface temperature. Heat radiation rate, per unit of surface area, is directly proportional to the emissivity characteristic of the surface. Emissivity = 1.0 (approx.) for a dull black surface; emissivity = 0.3 (approx.) Hence the rate at which heat is radiated from an engine block with a dull black surface might be roughly estimated as 3x the rate at which heat is radiated from an engine block with a shiny metal surface.
http://answers.google.com/answers/th...id/711843.html

 

Thanks for sharing!!!

 

That is why I lightly paint my Jeeps tranny coolers flat black and not leave then shinny aluminum.
Thanks for the info,
Jim

 

That is very interesting, thanks for sharing.

 

It would be nice to see this w/some lovejugs/fans blowing on the cylinders and see how accurate the sales pitch is about having fans on bike.

 

Great pics and information! Thank you for posting them up.

Do you have any thoughts on why the front cylinder is hotter than the rear...since it is more in the wind, it seems like the rear cylinder would be hotter than the front.

 

After reading your post I loaded the images back into my software and did a comparison of temperatures of the two cylinders. I found the highest tempeature in the front cylinder to be 351.8 degrees and the rear 332.9 degrees. A difference of 18.9 degrees. I also reviewed the visible light image and noticed the outer bolts on both cylinders are a different color than the inner bolts on each side of the spark plugs. This finding leads me to believe that at least on my 1200 the outer edges of the cylinders run hotter than the inner areas. It would be interesting to know if this is normal on Harley engines.

 

To answer my own question about head bolt discoloration on outer edge bolts, I have found several photos on google that display the same thing. Keeping in mind that my bike is nearly 15 years old the photos I found are from the same era. I will have too start asking other Harley owners if I can take Infrared images of their bikes to see if the temperature difference is common on all engines. Any takers in the Madison Wisconsin area?