When I clean out a tank, a solution of TSP (trisodium phosphate), dish detergent, and very hot water does a pretty good job of getting the crud outa the bottom of the tank. Leave the tank out in the sun for a day or two and all residual water will evaporate out. Or if you want to get kinda fancy (and can get it) use acetone to do the final cleanup. Use gloves and don't breath the vapors-it is absorbed through the skin or lungs and ain't too good for the liver and kidneys. Acetone, btw, is the standard prep for coating the tank (like with kreme). Kreem seems to be pretty tricky to get right-if you decide to do that, I can put you in touch with someone who's done it many times and can provide some tips.
Before you put the bike away for the winter, take it out for one last ride-run it for at least 10 miles so that it gets good and warm-you want the oil hot and you want any moisture in the case to be evaporated and outa there. On the way back, treat the gas in the tank with Stabil ™ and get it filled with fresh-from-the-pump gasoline. When you get to where you're going to store the bike, turn off the petcock and run the engine til it stalls-you want to get the gas out of the carbs.
Almost anything will fit if you want to make it, but the GPz1100 tank mounts differently at the front and the back
when I short the wires to the gauge, it reads full like it should. Has anybody had any luck repairing fuel sensors like that in the L4 ? No, it's not possible; it's a wire-resistance that sit's in fuel most of his life ;) if it gets dry; that's usually when the wire breaks,(corrosion, under influence of air, after soaking in fuel) i opened one up, but because of the agressive fuel it's almost impossible to weld it, in the end the gauge now works in the center ¾ of my tank :) have to put in on reserv as i read "empty". because the proces starts with the fuel gauge NOT in the fuel, while be4 it was soaking in it. better not to try a second hand one... pretty big chance it'l happen again(or the ones at the wreckers have already broken wires..)
I have read somewhere the way to get rid of the water is firstly drain the tank then put some cellulose paint thinners in the Tank, slosh it around, then leave to evaporate out, apparently it takes the water with it.
Water does wonderful things to fuel tanks - like rust them out.
So I have always put in quarter of a cup of metholated spirits into the tank every so often, to "absorb" the water globules.
anyway over this weekend I did an experiment. A jar of petrol with a few water droplets in it. The water "globuled" up at the bottom. I then added some metho. The metho "absorbed" the water nicely, but has not blended in with the petrol at all. The metho is sitting below the petrol, quite separate. I had expected the metho to merge into the petrol such that no obvious "layers" would be present. Now I'm wondering whether using metho is really the way to go.
If you want the gas level gizmo to continue to work, you gotta take it out. The acid you're using to clean the tank will damage the wires in the gizmo (changing the resistance) and the coating goop will act just like insulation. Not to start an ancient thread, but I used Kreem kit to seal this very leak. I followed the directions and I'm still satisfied fifteen years later.
If the brazed patch is at the rear tank mounting tang, it's a design defect to the model. This connection vibrates-flexes the steel tank, leads to cracks and gasoline leakage.
Classic GPz Tip: elongate two holes in the bracket that holds this tank tang to the frame in a rubber block (above the battery). The lengthened holes "relax" this connection: take stress out the tank, make re-assembly feel better, and should make the tank more durable.