hello, i have a 98 yz400 and was wondering just how do you know when a bike starts to overheat, does it lose power? mine seems to run fine, just wondering. also what would be the best sized sprockets, and flywheel weight to use for trail riding? This bike is all stock except the silencer, and o-ring chain that i added. I bought this off a friend that hardly rode it, still has original tires on it.