How to clean out a rusty gas tank, or clean anything with rust on it for CHEAP.

[SaltLick]

Forget about the expensive POR15 or Cream kits that run about $50.  I learned this while dealing with old hondas that had rusty tanks. One of the cheapest and best things to clean anything with rust on it is this:

Go to K-MART and buy two bottles of "The works" toilet bowl cleaner. $1.50 a bottle so thats a whopping $3.

Take your tank off your bike. Drain out your gas, pour both bottles of the toilet bowl cleaner in your tank. Every 5 minutes pick up your tank and slosh it around. After 30 minutes, pour that stuff out. Wash the inside out with dish soap and water. Rinse out multiple times with hot water.  Get a blow dryer and dry out your tank good, then fog it with WD-40 to keep it from flash rusting. Fill to the top with gas.

I have seen tanks from the 70's so rusty on the inside all you see is orange when you look in. After 30 minutes of the works cleaner it looks like bare metal brand new inside. This stuff also works for anything rusty, pour it in a pan and put your rusty part in.

[ducpainter]

What keeps the rust from forming again?

[SaltLick]

What keeps the rust from forming again?

if its a part or something else you just cleaned, i guess coating it with some oil. if its your gas tank, basically keeping it full of gas keeps it from rusting again.  I always just kept my gas tank full, or once i ran out of gas i just filled it back up. I didnt let it sit for too long on empty. The reason gas tanks get rusty inside is from sitting for along time with no gas in it, so as long as you keep gas in it your okay.

[mmakay]

Great tip.      As with any caustic cleaner, be sure to rinse VERY thoroughly.  It will continue to dissolve (slowly) any metal it is in contact with.

[brimo]

It's probably got phosphoric acid in it which is # 1 for rust. It also leaves a coating (iron phosphate) after you rinse it off that'll prevent further rust.

[powerhammer]

what if you've got an old Honda tank that someone used the JBweld type stuff to keep from leaking? 

Can i use this same process to clean/dry the tank if I'm going to cut and weld in a new section to fix the leak?

[red baron]

Plan on pinholes.

Make sure to use a tank liner when done.

Even factories phosphate of apply some type of coating to the inside.

[dbards]

Thanks.  Worked great.  I decided to get my 78 Yamaha running again.  It had been sitting in the backyard for 15 years.  It had rust in the 80's and  I tried a liner in it which came loose from the rust.  The cap was rusted on.  I had to take the petcock off and pour thru that opening.  In about 15 min, I got the cap off.  Most of the rust was gone.  Step one in getting it up and running.

[671M900]

Wanted to ad that water and some heavy molasses mixed in will kill rust fairly quickly, but will not keep it from forming again. I've used this trick on a few parts before painting them again.

The works is a good product, and I've successfully used evapo rust and Krud Kutter for Rust as well.