yz400f Radiator Overflow and Hot Start Button.

Hello, I just purchased a new to me yz400f. It is my first 4 stroke but i'm already in love. I have a few questions to ask the brilliant folks who browse these forums. I was driving the bike in my back field lightly for about 20 minutes today 3rd gear low-mid range rpm. when i brought my bike back i noticed vapor flowing out of the radiator overflow! and my exhaust had steam in it! When i opened the radiator cap and looked inside i could see the fins the coolant level was so low. I drained the coolant completely and added new coolant then the same happened again. I checked my oil to see if there was any coolant in it. there was none it was clear as a bell. What could be causing this?

When i touch the throttle it smokes blue. this all happen so suddenly.

Next is there are a few drops of goo that come out ofthe crank breather and a lot of air flow coming out too. the goo looks like the crank oil. is this normal?

I love this website and all the support provided. I'm hoping to learn a few things so that i can begin helping others! thanks again!

UPDATE- I got the hot start button installed (finally found it in the manual) A few things that are new. After driving the bike for a few minutes i started seeing puffs of blue smoke coming out of the exhaust. also there is a lot of air rushing out of the crank case breather (black hose that runs down front of frame) Bike runs great just smokes and overheats. If anyone can steer me in the right direction it would be greatly appreciated. bought the bike yesterday and think i may have been ripped off. Thanks!