Empty the gas tank of fuel and remove it from the bike.
Mask areas like the fuel cap that you do not want sprayed with masking tape. If you are using more than one color for the base coat, mask the areas that are going to be a different color.
Spray the paint evenly, in thin coats, back and forth across the tank. Apply a minimum of three to four coats, allowing the paint to dry in between.
Remove the masking tape. If you are using more than one color, apply masking tape over the areas you have just sprayed, and repeat Step 3 with a different color paint. (At this stage, areas like the fuel cap that are not being painted at all should remain masked.)
Allow paint to harden for 24 hours. Spray the tank again as described in Step 3; this time using the clear varnish. A minimum of four to five coats is required. Allow to harden for 24 hours.
Wet the sandpaper and sand the tank, keeping the sandpaper wet at all times. Begin with the most course sandpaper, then gradually use finer sandpaper, until you are using the finest grain possible. This is what creates a high gloss finish. Finally, apply polish to the tank with a soft cloth.