I just finished changing the coolant on my brother’s 2006 C50 and have a question. I disconnected the radiator hose at the pump, drained the old coolant, flushed the system with distilled water, reconnected the radiator hose, and slowly refilled the radiator with the new coolant. Then I rocked the bike back and forth several times to burp the system of air, and topped off the coolant again. I then started the bike with the radiator cap off, expecting the coolant to drop again and needing to be topped off. But it did not. As the bike began to reach operating temperature, the coolant actually began to occasionally bubble up and overflow out of the filler neck, then when I turned the bike off, there was a large surge of coolant that came out of the filler neck. The bike was running for maybe 10-15 minutes. I never noticed the radiator fan kick on, nor did the temperature light come on. At this point I really don’t know what to do next. Is this normal? Is it possible that I overfilled the system? I’m debating whether or not I should just drain the system and start over! Do you guys have any advice on what might be causing this, or what I should do next? I’d really appreciate any help you guys can give me!