over heating

[Arbby351]

Hi i have problem with it over heats plus lose water when its overheating but when take cap off when cold topup with water fulland turn run bike no bubbles but overheating. maybe airlock in system how can i bleed the system or HG gone. my bike kawasaki zxr 400.
plus if need to do head gasket whats torque setting on head bolts plz thx.

[Ewetea]

Since the radiator is located behind the front wheel, the matrix can become clogged with road dirt thrown up by the wheel. Also, the cooling mesh can become distorted due to small stones flicked up. This will all affect the cooling properties. To clean the radiator properly it must be removed from the bike. Soak it in a container for 24 hours and then use a feeler gauge blade to push debris out of the matrix from the back of the radiator. This will be tedious but inflict minimal damage. Do not use a pressure washer! The majority of the dirt will be in the centre of the radiator. Other suggestions for determining the problem of overheating: fit a new pressure cap; check the compression pressures on the cylinders - if two adjacent cylinders have low pressures then the head gasket will need replacing; is the fan operating when the temperature rises? Since the coolant system has clean fluid (I hope you have anti-freeze as well as water) the water pump is unlikely to contain debris which would inhibit the flow of coolant. If you do remove the radiator for cleaning you can also remove the pump for inspection and be sure that the impeller is attached to the shaft. Your bike is at least 25 years old so it is time for some TLC.