Fuel Tank Rust - how much is too much?

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  • Clean it

    4 100.00%
  • Run it as is

    0 0%
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  • 2 Post By pemdoc65
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  • 1 Post By Mickeyluv

Thread: Fuel Tank Rust - how much is too much?

  1. #1
    JCW
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    Fuel Tank Rust - how much is too much?

    I know, zero rust is desirable, but I'm posting this for opinions as to what you guys live with (or not). New to me CL450K4, new paint on all the steel bits so I don't want to use anything caustic to clean the tank, so would probably go with the vinegar and chains method. Before I yank the tank and start that process, what is the collective's opinion of this rust? The pictures show the rust which is above the fuel line (about 1/2 full) and the gloved finger pic was wiped from the dry top of the "hump" in the tank, above the fuel line. Should I just run it or mess with it possibly causing stuff to break loose later and screw up my carbs? It's only got about 75 trouble free miles since the rebuild so no telling if it is a ticking time bomb or not. Thoughts?
    Thanks,
    John

    Fuel Tank Rust - how much is too much?-20190531_114220.jpg

    Fuel Tank Rust - how much is too much?-20190531_114235.jpg

    Fuel Tank Rust - how much is too much?-20190531_114227.jpg

    Fuel Tank Rust - how much is too much?-20190531_114651.jpg
    1971 CL450K4

  2. #2
    Senior Member pemdoc65's Avatar
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    If it can rub off on your finger, it can get into the gas. I would give it a vinegar soak and rinse, then reassess. It doesn't look bad, though.
    JCW and Rob Axel like this.
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  3. #3
    Super Moderator frogman79's Avatar
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    That doesn't look bad at all, little vinegar a little time, job done. And when I say that I mean that process works, look it up on how to do it properly.
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  5. #4
    JCW
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    The collective here voted that I clean the tank, so I did and happy with the results. I ended up using two gallons of Evapo Rust and a length of chain I rolled around inside, rinsed with water and coated with Marvel oil. Should be good to go for quite sometime.

    Fuel Tank Rust - how much is too much?-aadad17c-e098-4a56-8483-0c39ffffe2e5.jpg
    1971 CL450K4

  6. #5
    Member Mickeyluv's Avatar
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    I've just completed a similar de-rust - just superficial surface rust due to condensation. I used a citric/phosphoric acid mix but decided to see if leaving a phosphate coating would offer any longer-term resistance. After rinsing out the tank I used a 50/50 mixture of 86% phosphoric acid and water and swirled this around to coat the inside. Afterwards I drained it but didn't rinse. Instead I used a combination of a hot air gun and compressor to dry off the inside, then left it over a low heat overnight. The inside now looks like it's been galvanized so I hope this lasts a little longer than bare metal.
    Rob Axel likes this.
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  7. #6
    Senior Member Rob Axel's Avatar
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    It is so minimal.. you can go either way.. I've gone the acid route.. it works good, just be safe and make sure you have plenty of baking soda..
    "Yes, my hands and nails have grease stains. I ride vintage!"
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