2008-2010 Kawasaki KFX450R Factory Service Manual, Page 154Get this manual
COOLING SYSTEM 4-11 Coolant
Cooling System Flushing
Over period of time, the cooling system accumulates rust, scale, and lime in the water jacket and radiatorWhen this accumulation is suspected or observed, flush the cooling systemIf this accumulation is not removed, it will clog up the water passages and considerably reduce the efficiency of the cooling systemDrain the cooling systemFill the cooling system with fresh water mixed with flushing compound