I havw a c50t, mine works great! One of our members has a c90, he has ridden both as I have and he likes his c90. The reason I purchased my c50 is that I needed more fuel capacity and longer distance out of each tank, a tour package, better handling and better suspension. I feel the c50 is the best all around bike EVER built. The fit and finish alone were a great selling point and once I took it for a spin I was in love. (i rode the 90 first) The power of the c50 was much better than I expected and I felt like it was almost exactly the same as the 90 in exceleration feel and power response (feel) I know the 90 shows better numbers on paper but it realy did feel similar on the road. As far as how the cooling works, the 90 and 50 use motion to generate air flow thru the radiator, and a back up fan for the c50 for hot days and sitting in traffic.