I am guessing this has been pointed out but here goes anyway. Just something I figured out last night (for us carb guys). Since you must apply vacuum to the petcock in order to drain the tank I found a very cheapo and clean route. Pull the vacuum line off the carb and route it around to the petcock side. Then pull the fuel line off the carb (there will obviously be a slight amount of gas come out). Then route a long line into a gas can from the petcock (duh). Now here is the cool part. Instead of buying a vacuum pump just put an very small el cheapo syringe in the vacuum line and just start pulling the syringe handle and there she blows!!!!

Not a big deal but I was happy LOL

Oh and I drained my tank because I was getting crapola in my carb bowl.