Thanks in advance for your help!

I recently drained the coolant fro my 05 BF 750. I assumed I could fill it back up through the reservoir, however, it does not seem to be taking in any fluid. I subsequently disconnedted the upper radiotor hose and was able to get some more in. I took it for a ride and I was getting the temp light. It also did not take in any more from the reservior.

Could someone explain the proper way to change the fluid?

 

It looks like you got air pockets trapped in the cooling system.
Jack up the front of the ATV so the front wheels are OFF the ground. Remove the radiator cap and squeeze various sections of the cooking hoses. This is to let air bubbles out of the cooling system. After that, slowly fill in the coolant in that exact position.

 

Can you get to the cap with out taking off the plastic

 

If you can get the cap off without taking off the plastic your better than I am. A note on refilling the cooling system. Remove the rad. cap and start adding coolant. When its full start the motor. As the motor heats up the system will cycle. Let it cycle as this will work the air out of the system when the coolant level drops just add more. continue this until the Rad. full. squeezing the hoses will help but it needs to cycle with the cap off the rad. Another thing is to check your overflow tube. Or just replace it overtime mineral deposits will build a fill on the rubber a restrict or even block flow to and from the radiator. For better cooling add water wetter to the system along with 50/50 mix antifreeze.
Hope this helps.