Checking coolant level

3 replies to this topic
  • rmcr250r

Posted November 14, 2009 - 08:17 AM


I want to check the coolant level in my 09 yz450 but in the manual it says somthin about pressurizing the radiators. Am i reading this right or am i just confused?

  • Yamaha8519B

Posted November 14, 2009 - 08:39 AM


Checking coolant on a bike is as simple as taking off the radiator cap. You want it filled to the top.

The pressurizing is probably talking about pressure testing to be sure there is no leaks. This is not necessary unless you have mashed up your rads in a crash or have reason to believe they are leaking.

Sometimes the left side radiators have a bolt on top of them. When you fill it up take this bolt off and fill the radiators until coolant comes out of that bolt hole. This insures that air isn't trapped preventing the radiators from being completely filled. It may have been referencing this but not sure if YZFs have that or not.

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  • rmcr250r

Posted November 14, 2009 - 08:55 AM


thanks i knew it would be simple just didnt understand the pressurizing thing

  • micahmorgan

Posted November 14, 2009 - 07:10 PM


I wouldn't fill it up all the way to the top. I'm pretty sure the owners manual says to fill up to the radiator cap, but if you do, it will just spilt some out once the motor is running. I fill mine up just above the fins when looking inside the radiator.

The pressure thing mentioned in the manual is to ensure that the system remains pressurized. I'm sure it's a good idea, but I've never even seen this done.

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