Fitting a XS850 gas tank to KZ1000 frame

Hello All, I need to replace the tank on my 81 KZ1000 LTD - the current tank is pretty roached, even after numerous attempts to clean it out and lining it with Red Kote.

Essentially, I have an 82 Yamaha XS850 tank in good shape laying around that I would like to attempt to use instead of buying a bolt on KZ tank, however to fit the XS tank to the KZ frame, I'll need to cut out and weld the bottom center of the tank and make the tunnel a bit larger for the tank to sit level on the frame. In addition, the Yamaha tank runs off a dual vacuum petcock setup, should I keep the dual petcock system and use T's to join the vacuum and fuel lines? Or should I solder the right side shut and run off just the left side petcock like the KZ tank on the bike?

If I pick up a high speed cut off tool and a 70amp stick welder from Harbor Freight will I be able to accomplish this project? I've never welded before, so I'm looking forward to teach myself how to weld. Any recommendation for tools/equipment (really looking at cheaper ones from Harbor Freight, since this is a hobby for me) would be appreciated.

I've never done a project like this before, and would appreciate any tips or instructions y'all would be able to provide. I've budgeted between $200-$300 for tools and materials to make this tank work (I know I can probably buy a nice bolt on KZ replacement for this price, but I'd rather give this project a go and learn something new).

Is this more work than it would be worth? I've attached a picture of the bottom of the XS tank for reference.

Gas tanks are relatively thin gauge metal and need a perfect weld not to leak. An Arc stick welder would not be my first choice for thinner gauges due to the higher heat. You're probably going to burn thru more holes than you started with. I normally try to encourage learning a new skill by tackling a challenge you've never done before. However, a gas tank is not the best choice to perfect your stick welding skill. If you're still bent on doing it, consider buying an an oxyacetylene torch and brazing it. IMO, spending the money on a replacement tank would be the best choice.

In my opinion, this is a bad idea because--

the design of that tank necessitates two petcocks to access all of the fuel. Not using the fuel on one side will encourage the accumulation of water, which will rust its way to the outside.

the forward mounts look very different and will likely require significant fabrication. The rear mount may, too.

a fuel tank as a first welding project seems like a shortcut to the hospital. Even if you avoid an explosion, that metal is thin and very easy to burn through, and you may end up with far more leaks than you currently have.

ymmv

Zachgrove1 wrote: .......................
Is this more work than it would be worth?

Yes. Not only is it more work that it is worth, it will not look particularly good when finished since, IMHO, the shape of the tank doesn't work well with the rest of the KZ1000. Ed