Fuel Tank Rust Removal

[RustyJC]

Long story short - I have a 1971 Honda CB750K1 in the garage that I've owned since it was new. I haven't ridden it in a number of years but have undertaken a spare time project to get it back on the road.



Checking inside the fuel tank, I found a light coating of surface rust in the areas above the fuel level (before anyone asks, I ran the carbs dry before I shut it down, but there's still some stale fuel in the tank that I'll have to dump). This isn't scaly rust and doesn't come anywhere near perforating the tank; rather, if I run my fingers over the area around the filler neck inside the tank, it feels sandy and my fingertips come out orange.



Anyone have any suggestions for a simple, effective method of rust removal? Vatting the tank is out, of course, since the original painted finish on the outside of the tank is in excellent condition, and I don't want to damage that.



Rusty

 

[rscurtis]

I've cleaned dirty fuel tanks with solvent and small (pea sized) bluestones. Agitate the tank until the solvent runs clear and then remove the stones.

 

[fest3er]

If you can get a soft scrubbing tool (like a cloth bottle/jar cleaner) to the surfaces, you could try Bartenders' Helper. It's a mild oxalic acid. Cleans tarnish, rust stains, organic matter and scale off metal and porcelain, but I've never tried it for removing actual rust particles.

 

[RustyJC]

I had this bright idea to try pouring a bottle of CLR (calcium, lime and rust remover) in the tank, sloshing it around, flushing it out and then coating the inside of the tank with WD40. Wonder if that's worth a try??



Rusty

 

[NIsaacs]

Whatever you do, be sure and get all the little sandy particles off/out of the tank. They are so fine they will flow though an inline fuel filter and jam the carb fuel float needles and flood. I am always working on old vehicles (can't afford new) and have had to use sediment bowl type fuel filters to stop the tiny sand particles.



Nick