To get the most fuel in the bike fill it up when it's on the center stand. Word of caution though, fuel will leak out of the left tank when parked on the side stand (when both fuel tanks are full). I park my bike on the center stand until I ride 30-40 miles and use up some of the fuel.
If you're riding slow and technical there's a chance your fuel tanks will pressurize. This is most commonly caused by a pinched vent line when putting gas-tanks back on the bike (though there are other causes). If the gas tanks are pressurized and you open the gas cap fuel will explode out of the tank and into your face.
If you have a right side fan kit installed it's a good idea to buy, build, or create a fan shroud to keep the hot air from blowing onto the gas tank and boiling your gas (really only a problem in slow, technical riding). Many people use KTM OEM part number 60035044050 ($6 or so) and modify it.
"All that is gold does not glitter,
Not all those who wander are lost;
The old that is strong does not wither,
Deep roots are not reached by the frost."
'12 690 Enduro
// 690 Wiki
TheMuffinMan screwed with this post 03-06-2012 at 05:18 PM