I fought overheating on my 08 450EXCR from the first day I rode it. I have re-jetted (JD), removed smog, removed restrictor on exhaust, re-geared, and added overflow can. I have run blue, pink, red and green coolants. I ride on a variety of terrain, mountain trails and desert. The bottom line was if I did not keep moving at a steady pace the bike would overheat. And I mean overheat, not just puke out the expanded coolant at the top of the radiator. I had to carry extra water with me and usually had to use it. I read somewhere on this site that you had to maintain at least 8MPH to avoid overheating, but I think it is actually much more than that. After reading this and other sites, I came to the conclusion there were only two things left to try, a fan kit or evans coolant. I had read about the drawbacks of the fan kit and was not sure I wanted to go that way, so I tried the evans. It is somewhat hard to find, and you have to make sure that you remove all the water from your system, but after I started using it last spring and putting 1500 miles on the bike since, I have not lost any coolant and that was with a few summertime rides in the desert.