675 Coolant loss

Picked up my 955 street triple on Saturday and rode it into work on Tuesday. When I parked up I noticed a small pool of coolant forming unfer the left hand side of the engine. I rode the bike home slowly keeping one eye on temperature reading, reached 195 in town and 175 out of town. Checked the bike over last night and noticed that the expansion tank was low but there is plenty of coolant in the system and it doesn't appear to be contaminated. Topped the expansion tank up, started the bike and let it warm up and I got another puddle on the floor (the coolant is exiting via a small pipe near the pump). A quick search seems to suggests that the expansion tank is best checked when hot or filled to below the minimum mark when cold, is this correct or should I be worried?