Alot of bikes come with black painted rads, like most of the Yamahas...A light coat wouldnt hurt IMO...And Im pretty sure there are some theory's out there about some black paints dissapaiting heat better then other colors or unpaited surfaces...Not sure if it matters what paint, or matte vs gloss etc...

Im a believer that the non coated Aluminum radiators dissapate heat better, but also absorb it faster too. Being that close to a header, Id want mine coated. Hondas come w a black coating of some sort too. A light coat wont hurt at all, just dont go bananas on the fins.

Yeah It cant be bad to paint things black because of heat, because every manufacturer is starting to paint everything black...Including engine cases and oil pans...If it would hold more heat they wouldn't be doing this

Yeah....except for the fact that anyone with much knowledge of motors will tell you that the hottest temperature a motor can run at, without melting itself down or causing internal failures.....is the most efficient temperature for such motor to run at...

Also....since we're talking aluminum here.....how many aluminum race radiators, such as Griffins....do you see with ANY coating on them? And normally, most racers leave them uncoated....from what I've seen...gotta be a reason behind that...

I believe most main stream manufacturers these days try to put a "shelf life" on all their new vehicles. They could be going for looks, instead of reliability....

a little paint would help keep the aluminum from oxidizing and that impedes heat transfer too so maybe they dont paint them so you will have to buy another one sooner

not painting them saves them money