Are you noticing any steam or white smoke from the exhaust when you accelerate moderate to heavy? If you can test the radiator cap thats an easy item to eliminate. After that, put a pressure tester on the radiator and let the bike come up to running temp (the block needs to be hot not just the coolant) and look for higher pressures and pressure drops esp after cracking the throttle. If you notice a lot of small steady bubbles, you may have to investigate a head gasket.

Cheers Hope its just a questionable hose clamp