[Dale Meche]

Dale Meche  asked the Naked Scientists:
   
I am trying to find something to clean some rust from a motorcycle gas tank. Can I use vinegar to clean the rust out of gas tank?

I have already removed most of the rust, but I'm still having problems with a small amount of rust getting through to my carburettor.

What do you think?

[SeanB]

Drain the tank, then pour a whole bottle of rust remover jelly inside, shake well for a few minutes after sealing it and then clean it out properly, rinsing well a few times with both water and soap, and some thinners or other organic solvent. Once all the rust remover has been removed the inside should be nearly spotless, though you will have to dry the tank inside with either methanol or methylated spirits before you refill with petrol. To prevent it rusting again keep the tank full, and add a little 2 stroke oil to the initial fuel, around 100 to 1 fuel oil mix will provide a thin oil layer inside the tank whilst not smoking too much.

[Don_1]

I would ask the question, how is the inside of the tank getting rusty in the first place? Is the fuel contaminated or does your filler cap need replacing?

Rather than risk buggering up the carb, I would get a new tank.

[CliffordK]

Rather than risk buggering up the carb, I would get a new tank.

That is not always possible. 

I believe that many of the newer vehicles are now coming out with plastic fuel tanks.  But, the older vehicles will have some rust. 

A 20+ yr old daily driver may get some rust in the tank, but generally it is not a big issue. 

A 30+ yr old classic that has been sitting around for the last 20+ years will undoubtedly have rust in the tank. 

Unfortunately, one can't always find a replacement tank for all of the classics. 

I was going to try a plastic fuel tank sealant/coating kit for one of my vehicles.  However, I've started experimenting with alternative fuels which have a tendency of softening stuff that petroleum fuels don't bother, so I've been reluctant to do the tank coating.  I suppose, if I make a mess, the worst thing that could happen would be that I'd have to build a replacement tank out of stainless.