Join Date: Jun 2008
Location: Lethbridge Alberta
Model: 1999 GL1500 SE 50th Annv.
The drain bolt on the tank. I doubt after all this time that you'd be able to get it out without damaging the tank. I know I never could on some old wings I had. In draining the tanks on these old bikes, I've removed the top part of the tank and used a syphon to get the bulk of old gas out and the remainder will evaporate. You'll likely have to make a new gasket where the sender unit goes on the tank as once they are disturbed they usually leak.
1983 GL1100, 2013 Suzuki Vstrom DL650
Previous bikes - 1971 BMW R75, 2008 HD Softail, 2000 BMW R1100R, 1980 XJ650, XT500, GS550, 77 GL1000 x2 and a few others