Coolant draining from overflow reservoir

I recently did a starter valve synch and went for a short ride on my 04 in Texas heat of 92 degrees to get it ready for a long trip next week.
Seems that idle was running higher than it should so when I got back to the garage I kept the bike running on the side stand to adjust the idle and noticed a puddle of coolant draining from the overflow hose and I hear lots of gurgling noises.

Why is this happening?
I've owned the bike a year and this has not happened before.

 

A guess here. The gurgling is boiling possibly. If it is boiling, you have a leak in the system. Do a pressure test on the system. That is the logical first check and it is cheap.

 

REPLACE YOUR RADIATOR CAP! Sorry for the all caps, but I lowsided when my bike did the same thing and dumped coolant on my back tire. It's cheap, you don't need a Honda cap, you can get one at the local autoparts store for about 30% of what the dealership charges.
This should be your first step. It's only about $6-$7.

 

It seems crazy, but mine was doing the same and it actually was the cap. (I say 'crazy' because usually the cheap and easy fix is never what you're lucky enough to make work)

My cap was a little gunked up, the spring compression was not smooth at all, and the bottom rubber ring was starting to degrade in the middle.

 

I had similar issue too, turned out it was the radiator cap. With any luck, it'll be the same for you.

 

Thanks for the help!
In the forum I found that this radiator cap will work:
Murray Ultra 7516 $7.99 (O'Reilly's)

Will replace the cap and likely flush and refill coolant too.

 

Replaced the radiator cap, flushed and refilled the coolant; seems that this solved the problem. I had gone out for a short ride (1/2 hour), the temps ranged between 190F and 202F once the engine warmed up, then jumped into the 215F-220F range when stopped in traffic; heard the fan kick on....no problem.

Thanks again for the help.