How do I drain the fuel tank?

Obviously, working with gasoline can be lethal. Plan your work area accordingly; this isn't something you want to do in the living room. Plan on spilling at least some gas.

Quick way

If you're careful, you can skip the whole vacuum pump process (see below) and go straight to pulling the petcock.

• Remove the tank from the bike
• Pull the petcock off; this involves turning the tank about 3/4 upside down, so the petcock is at the highest point. This will help prevent mass spillage.
• Dump the fuel into a 5 gallon bucket. The gas will come out rapidly; it should take less than a minute to empty the tank, and that's if you're going slowly and trying not to splash.
• Replace petcock
• Empty bucket into someone's car
• Use someone's car to go to the gas station, bringing the Ninja tank with you
• Put new fuel in the Ninja's gas tank at the station

This is about a 20 minute or so process, unless you don't follow the "use someone's car to go to the gas station" bit, in which case it could take longer, depending on how fast you can walk.

Vacuum pump way

• Buy a length of hose that has the same inner diameter as the large fuel line, and that is long enough to reach from the petcock to the ground.
• Buy a 5 gallon fuel can.
• Buy a hand-actuated vacuum pump, like what you get inside a brake bleeder kit. Better yet, just buy a brake bleeder kit.
• Disconnect the vacuum and fuel lines from the petcock.
• Hook up your fuel line; place the open end into the fuel can.
• Hook up a vacuum line between the petcock and the hand-actuated vacuum pump.
• Set petcock to the on position.
• Pump hand pump several times until it's around 20 in-hg.
• Gas tank will start to drain.
• Check the hand pump every now and again to make sure it's between 10 and 20 in-hg.
• When the fuel stops flowing, switch the petcock to the RES position.
• Fuel should start flowing once again.

When fuel stops, disconnect the hand pump and the fuel line, seal up your gas can (after adding an appropriate amount of Stabil, assuming you're going to store the gas), and hook up the fuel and vacuum lines to the petcock.

Here's a photo of the Jim Race not-club-sanctioned way to do it. We suggest you omit the shopping cart, and the basketball. It does, however, give you a good idea of the relative locations of the vacuum port and (larger) gas line drain.

Sealing tank openings for cleaning

The tank shown below had a bit o'rust in it. Here is how our man sealed it up for derusting so the chemicals didn't affect the lock, leak out the keyhole, or hurt the petcock.

Inlet (gas cap) plug

Use a 1 13/16" x 1 1/2" x 1" rubber stopper, in this case the largest one Lowes had in their hardware section. Fits ok if you press by hand - fits tighter after a whack with a rubber mallet.

There should be other sizes that will work, as will some bathtub stoppers.

Outlet (petcock) plug

Make a plate to fit in place of the petcock out of scrap aluminum or wood. This one is about 1 1/4" x 1/4". Space the centers of the holes at 1 3/8" using a 1/4" drill bit. Smooth off the burs and rough edges with an electric wire brush. Cut a matching gasket from cork-rubber gasket material or bicycle innertube and bolt the plug into place on the tank.