[Nighthawk]

Well first off, you lay down some masking tape on top of your tank (BMW Plastic). Set the tank bag where you want and draw around the tank bag to make a foot print of the bag. Now mark where the gas cap is along with the filler cap bolt holes. Remove the tape in one piece. Mark where the magnets are in the tang bag on the tape. Transfer the tape to some sheet metal and mark the metal. Cut the foot print out and smooth all the edges. Drill the holes for the filler bolts to go through so you can mount on top of the gas tank (and a hole for the gas cap). Form the metal to your gas tank. After a dry fit and everything works, remove the metal and paint the top to match the color of your bike. Glue some 1/4" pad to the under side of the metal. Finish by installing auto trim around the edge of the metal. Mount using spacers about 1/4" high between metal and gas filler neck. And now you can us a magnet tank bag on a plastic gas tank. I know they make straps mounts for this, but where is the fun in that.