KZ900 Tank Pinhole - What are my options?

Hello,

The bike is a 76' KZ900. Just recently I went to clean the tank of rust, which was pretty thick, scaley, chunky and nasty. Using the vinegar with nuts and bolts method, I filled it up and went to town. After some aggressive shaking, I noticed a leak coming from the side of the tank. To me it looks pretty small, but it does drip continuously about every 30 seconds. The tank has been sitting since the late 80's, and I only noticed this one spot that was leaking. Although, I can imagine if it's leaking here, there's got to be other pretty thin areas...

I wanted to get some opinions. I've read through some articles where POR15 or Caldwell tank liners can be used. It's a low mileage bike, but was modified back in the day so it's certainly not a true original. That said, in a perfect world, tank repair would be the proper fix, but I don't really want to repaint the bike at this time. What would you guys do? What would you suggest for a small leak like this?

Regards,

Erik
 

Is the tank rust free now?  If not I'd seal the leak with tape and continue derusting until clean. 

After fully derusting,  if any leaks you find are small and minor, then POR-15 would be a good option. If the metal is thinned and you get a bunch of leaks, Caswell may be better because it's thick and sturdy.  It's harder to work with though and will add weight to the tank.