Major modifications to tank / welding etc..

I need to modify my tank to have a return for efi. I have the petcock and return off an 83-84 gpz tank that I could weld into my tank but this looks like a major undertaking to me and I am also considering changing out the gas cap for a more modern sportbike setup. I know welding a fuel tank can be very dangerous so I am researching this very carefuly before pulling the trigger. I also hate to cut up a nice tank with the possibility of ruining it. Maybe Im overlooking some easier way to get a return back into the tank. Im going all out here if I cant find a simpler solution. Any ideas or has anyone done this before? Im working with a gas mig so it's not the ideal setup for this kind of fab work.

What Im working with.



I even considered a zrx tank but it just dosent look right to me.

jydog,

I was going to do the exact some thing and replace the filler cap with a ZX10 unit I have. However after doing some repair work on the tank with my MIG I quickly figured out that it was not the ideal method and will quickly burn holes in the tank. I got away with it as all I needed to do was tac some material in and clean it up, but I think doing the cap would require going another direction, possibly TIG.

As far as the return is there any area available on the float plate that you could tap and use? If so, may be the easier route. Otherwise, I would have a 1x1 1/4 plate welded somewhere on the tank and then tap it.

Very nice looking bike. I have to ask, are you in love with the fuel gauge? I almost think I would take that apart and drill and pipe tap that cover and put the return there? It may not be the ideal place but it would keep you from welding on your tank. I would think any bung that gets welded would need support around the base like the factory does on the inside and outside.

I weld sheet metal every day with a mig welder. As long as you set the machine up correctly and take your time you'll be fine. In such a small area it would be best to make tack welds and let them cool before putting more tacks on. If you are worried about gas vapors fill the tank with water to dispense the fumes. When your done put rubbing alcohol in it to evaporate any moisture left from the water.

I agree with Andy. Get a roll of 0.023" MIG wire for welding sheet metal. It makes it so much easier. I did a fair amount of welding on my tank that way. Still holding gas a year later.

Is brazing totally out of favor now? I am planning on brazing a 5/16 steel tube into my tank for a return line.

I enjoy torch work

Actually, I did discover one minor pinhole leak after testing my welds. I brazed that one shut. The torch is quite satisfying as well.

Now you guys got me thinking maybe I can put that ZX10 filler in there!! I think my issue was mig to hot and area I was repairing was super thin.

if you need a way to tap into a tank again look into a bulkhead fitting all you need to do is drill a hole they work great and you can them as small as 10/32. takes away the need for welding

What would be the best source for a gas cap? I thinking a kawasaki 51049-1079

part number cross

looks like a lot of kawasakis use this.

Tap the fuel sender? I'll definitly try this first if I decide not to weld, But for now Im leaning toward welding. Nothing risked, nothing gained.

The bulkhead fitting is a great idea but I would be afraid of leaks since it has to come from the bottom. How reliable would this be and would you have to have access to the inside of the tank to secure the fitting?

I was going to try and use the return check valve from the gpz efi and the fuel petcock but after looking at them they are not in the best shape and what benifit would the pingle petcock be over stock?

I would try brazing but that would be a new learning curve for me so for now Im going to stick with my mig.

Thanks for everyone's input. I think Im going to try to source a cap and mount ( if anyone has one for sale with the mount and key let me know ), weld an aftermarket return check valve in and use the stock petcock.

Just an idea about changing to a modern gas cap. Find a cheap, beat up tank on Ebay with the style of cap that you like. That way you can cut out the sheetmetal around the cap. Just take an extra inch around the circumference of the cap so you have something to weld to. Then cut out the same size hole in the top of your KZ tank and then weld it in. Make sure to keep the hole very close to the same shape as the donor filler neck piece. You don't want to be trying to weld across big gaps with that thin of sheetmetal. It burns through way to easy if your fitting job isn't precise.