I meant the vinegar, which is probably not good for the gas.
I used it on a Honda tank, worked great but I rinsed the vinegar out with a garden hose now it is starting to rust again. I can't fill it with gas because there is no bike to go with it and the lack of a fuel valve.
They flash rust amazingly fast after an acid treatment. You might try spraying the inside with WD-40 after you flush out the vinegar with water. That should displace the water and help to keep it from rusting right away until you can get it lined or back o the bike.
I restore vintage bikes, so I'm restoring rusty gas tanks all the time.
The best rust remover I have ever found is "Evaporust". I buy mine at O-Reillys Auto Parts because they stock the gallon size. (It's cheaper by the gallon.) It removes rust better than anything else I've ever tried and it's completely environmentally safe and safe to get on your hands.
When you get the rust removed, you're NOT DONE. The tank will flash-rust within a very short time after rust removal. (In minutes, not hours).
You have to SEAL the tank immediately after rust removal. The best sealer/tank restoration kit I've ever found is "POR-15 Motorcycle Fuel Tank Repair Kit". Here:
I've used others, including Red-Kote, but the POR-15 Kit is the best. I've done over a dozen gas tanks with it. The POR-15 kit comes with its own rust remover called metal prep. That will be enough for a tank with just a bit of rust in it. But, if your tank is completely rusted inside top to bottom with heavy rust, your gonna need some Evaporust first before you use the POR-15 kit.
Do it right the first time, or you'll be doing it again soon after.
A trick I learned when I restored a few gsxr's that were left to rot in a junkyard was apple cider in the gas tank, let sit for a week or 2 and just make a point to go out and rotate the tank around to wet the areas that may not be filled up to. Dump it and see how it looks than rinse and repeat as needed.