My understanding is air-cooled is better than liquid-cooled, since the liquids will shut down. I completed a ride from Ontario, Canada, to California this summer. Went down and back in 8 days. 10,000 km's. Went through the south, and came back along US70. Stopped at the Painted Desert, Grand Canyon, Valley of Fire, Mojave Desert, and Arches National Park. I did it during the heatwave. The hottest it got on my Dakota Digital air temp gauge while driving was 116F. 14 to 16 hours in the saddle all day. I run Amsoil. Bike ran just fine. Bit of a noticeable drop in power at some of the hotter periods, but she chugged along fine. Stock 96" motor, Stage 1, cams, 2-1 exhaust.