Vintage Dirt Bike Q & A

I am trying to get the rust out of my tank and re-seal it. The problem is the petcock. A friend told me to use muratic acid but when I take the petcock off there are two big holes in the bottom of the tank. Please help

Wrong acid. Use phosphoric acid to get rid of the rust.
Leave the petcock installed and switch it off.

If your going to leave the petcock on I would consider rebuilding it! There are O-Rings there that you will need to replace!

Personally wouldn't you want the petcock off? Try a radiator shop they can dip the tank for you & get rid of the rust! Hose the tank out good before you take it to them.

Good Luck

I recently restored a rusted tank on old yamaha enduro. There was a failed coating already in there, so I got the POR15 HD Cycle tank kit. Cost was around $30 or so I believe. The petcock was, shall we say, southern engineered, missing both screens and reservoir tube. I found a NOS petcock for $20. So for $50 or so you can have a functionally restored tank. I've ran about 3 tanks of 91 unleaded premix through it with no problems whatsoever. The instructions with the kit are plain and simple and playing with chemicals is always fun, too!

good luck
ryan