This is how I do a coolant system flush. You'll need 4 quarts of 50/50 coolant mix. I use Pro Honda HP coolant (or equivalent) mixed with distilled water in equal proportions. And you’ll need an additional gallon of distilled water (Do Not Use Tap Water).
With the engine cool, remove the radiator cap (Under Right fairing pocket) and then the 8 mm radiator drain bolt above the oil filter (See photo below), this will drain the coolant. Go to the radiator filler neck, and start pouring the one gallon of distilled water into the filler neck. When all the radiator fluid and the distilled water is done draining, put the 8 mm bolt back in. Do not over tighten, it has a copper sealing washer on it (The Service Manual says to replace the sealing washer with a new one, but I usually don't unless it's damaged). Now pour in the new coolant mix. After three and a half quarts of 50/50 mix have been added, start the bike and let it warm up. When the bike is at operating temperature snap the throttle a few times to bleed the air out of the system. It will bubble up in the filler neck and the fluid level will drop a little. When the air is out, top off the radiator back up to filler neck (3.7 qt. is required to fill radiator and engine). Replace the radiator cap and you're done!
It's also a good idea to flush out the radiator overflow reservoir while you're at it. To refill the overflow reservoir with new coolant, will take 0.69 qt of 50/50 mix.
Note: If you plan on doing this procedure yourself regularly, you can look into purchasing a uView 550000 tool for purging the air out of the cooling system. It removes the air more efficiently than the above procedure and makes this job very easy.