Found these online.... refers to radiators on cars, however I bet the concept is the same.
A radiator cap pressure ranges from about 14-15 PSI for most modern vehicles, while many aftermarket high pressure radiator caps can increase this pressure to between 18 and 20 PSI. High performance racing radiators may have caps rated at as high as 22-31 PSI, but these should not be used on a factory radiator. It is important to select the pressure rating that is recommended for your vehicle in your owner’s manual. Too low a pressure will decrease a coolant’s boiling point, while an excessively high rating may increase the chances of a coolant leak.
If the coolant cap is bad, the fans may come on but the bike will still tend to overheat. A bad coolant cap will really show itself if you are riding with a good airstream crossing the radiators and the temp is still rising a little.
A radiator cap pressure ranges from about 14-15 PSI for most modern vehicles, while many aftermarket high pressure radiator caps can increase this pressure to between 18 and 20 PSI. High performance racing radiators may have caps rated at as high as 22-31 PSI, but these should not be used on a factory radiator. It is important to select the pressure rating that is recommended for your vehicle in your owner’s manual. Too low a pressure will decrease a coolant’s boiling point, while an excessively high rating may increase the chances of a coolant leak.
If the coolant cap is bad, the fans may come on but the bike will still tend to overheat. A bad coolant cap will really show itself if you are riding with a good airstream crossing the radiators and the temp is still rising a little.
