Hi good people, im new to this forum and also very green with bmw bikes. I absolutely love my HP4. My only problem is that she drains coolant out of the expansion tank once the engine is hot. While engine is running, she drips in bits(Noticed this while a buddy was riding it). And when one comes to a stop and kills the engine, theres a boiling sound from the expansion tank, and coolant drains to the ground. So i have to constantly top her up each time before i ride.. lastly, ive thoroughly checked the radiator for leaks and i confirm it has none. Please help