Routine maintenance is key to keeping your machine on the trails or track longer with less downtime for repairs. The cooling system can often be overlooked at times, but in reality it needs just as much attention as the other moving parts. Without the cooling system working properly, you can experience many different mechanical failures, such as overheating, burst hoses or coolant leaks. For this “How-To” we show you how to replace the radiator hoses, water pump impeller and coolant on a 2008 Yamaha YFZ450, but the steps apply to any liquid-cooled machine. We contacted Boyesen for its SuperCooler kit, along with tough silicone radiator hoses from CV4. We also chose to upgrade the cooling system with an Evans waterless coolant. Evans coolant aids cooling, but most important, it does not boil out of the overflow like a conventional coolant. That helps maintain the coolant volume in tough conditions.
To drain the coolant system you will find the drain plug located on the water-pump cover. This 8mm bolt is removed, allowing the system to drain in a pan. You can remove the radiator cap to relieve pressure for a faster drain. You need to take care at this point to keep the coolant contained. You don’t want to spill the coolant.
</hatul>Step 3</u>Remove any additional hose fittings from the cover, as these will be installed on the new Boyesen cover. Clean any parts that show signs of calcium buildup or rust.