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Cleaning fuel tank

Discussion in 'XJ Technical Chat' started by weeboy1, Apr 20, 2022.

  1. weeboy1

    weeboy1 Member

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    Hi all, Have an 83 xj750 garage find. Sat for 15 years with fuel in it. It actually looks pretty good inside. Some surface speckling and a bit of rust stains and tiny particles in the very bottom.
    Wondering the best course to clean and flush . By the looks of it I don’t believe it should need drastic measures.
    See pics below,
     

    Attached Files:

  2. Dan Gardner

    Dan Gardner Well-Known Member Premium Member

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    That actually looks pretty amazing! I don't know if you have to do anything to the tank besides rinse it out with a little fresh gas.

    Hopefully the petcock survived in as good of condition as the tank and it works properly, if not, of course you'll need to deal with that.

    Should make sure you have an inline fuel filter between the petcock and carbs just make sure no random crud makes it to the carbs - no matter how clean the tank looks.

    If you can, avoid oxygenated (ethanol) fuel.
     
  3. Huntchuks

    Huntchuks Well-Known Member

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    Looks good except for the seams and it is hard to tell how good or bad they are from the pictures. If not bad, I think I would soak some evapo-rust in it for awhile, letting it sit in the seams. May as well get rid of any rust while you can.
     
  4. weeboy1

    weeboy1 Member

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    Thanks for the input. I’d like to be able to rinse it out with just premium gas and hopefully get it clean that way. I’m a little hesitant about putting etching chemicals in there when it doesn’t look that bad overall. Also I plan to add a fuel filter for sure.
     
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  5. Huntchuks

    Huntchuks Well-Known Member

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    Evapo-rust is not an acid, is safe on your skin and down the drain. Look it up.
     
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  6. RockinRich70

    RockinRich70 New Member

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    I have done a lot of research on getting rust out of a tank. What I have come up with is that Evapo-Rust is the way to go. Its not an acid and it says it won't ruin the paint. I tried it first on some lightly rusted tools, and I am happy with the results. I will be doing my tank as soon as it warms up. It works better the warmer it is. I may even put a space heater near it when I fill the tank, to get the best and quickest result. Follow the instructions to the letter.
     
  7. Blackbird

    Blackbird Member

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    Totally agree with the Evapo-Rust reviews. I have used it many times and keep a couple 3 1/2 gal pails on hand so I can fill the tank to the top. It's also reusable. I will also throw in a handfull of small stainless steel nuts and shake the tank to get any stubborn rust out. Mine cost me about $50 a pail on Amazon but like everything else has gone up a bit.
     
  8. weeboy1

    weeboy1 Member

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    Thanks, I’ll “look it up”
     
  9. Huntchuks

    Huntchuks Well-Known Member

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  10. weeboy1

    weeboy1 Member

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    What would be the best procedure for me to follow? Given that the tank does not appear to be too bad can I clean and rinse the tank, dry it out and then add say 1gal of evapo-rust. Then let it sit in different positions to contact all surfaces prior to rinsing accordingly. Some info indicated filling to top but I’m not sure that’s necessary in my case plus the stuff is not cheap and I’ll only need it once.
    Thanks for the help.
     
  11. Huntchuks

    Huntchuks Well-Known Member

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    It looks like you could just use a gal. and let the tank sit in different positions. Looks like most rust spots are at the bottom seam so that is where you want to concentrate it. If it were me I could plug the fill hole and turn it upside down for awhile though, just to be sure.
     
  12. weeboy1

    weeboy1 Member

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    Thanks appreciate the input. First up is getting the carbs off for a cleaning and dealing with the air box boots….heard to heat them up and push them back against the air box. Sounds simple enough, not sure about getting them back out and in place again.
     
  13. XJ550H

    XJ550H Well-Known Member Premium Member

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    when you want to reinstall put them in a bucket of hot water then you will be able to install air box side then to carb
     
  14. weeboy1

    weeboy1 Member

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    So are you saying that after I push them back to the air box and remove the carbs I’d then remove the boots from the air box, replace carbs into manifold and then reinstall boots after heating in water? This kinda makes sense due to the tightness of the area. Sorry for all the questions, I’m a Harley guy and learning the xj as I go so all the help is definitely appreciated.
     
  15. XJ550H

    XJ550H Well-Known Member Premium Member

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    i found that easier than heating with a hair drier to reinsatll with them in the air box.
    when you take them out of the water the boot will bend easy to reinstall in air box then onto carb still may need hair drier to get them on carb depending how quickly you work . I do carb 2 then carb 1 then go to other side of bike for 3 and 4. not 1 ,2,3,4,
     
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  16. weeboy1

    weeboy1 Member

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    Thank you!
     
  17. Brent NZ

    Brent NZ Active Member

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    Hey guys, I removed and flushed the gas tank today, and found grubby fuel & rust flakes in the bottom. Doesn't look bad from the filler cap end, however something must be amiss in the further recesses.
    Some youtubers recommend soaking with vinegar then flushing with water. Is that a good idea or is it better to seal with specialised products?
     
  18. XJ650inTexas

    XJ650inTexas Active Member

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    Soaking in vinegar or acid will remove the rust, etc.. I did that then used the Por-15 tank sealer kit and so far the tank still looks new inside.
     
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  19. Brent NZ

    Brent NZ Active Member

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    I put a couple of handfulls of nuts in the tank & gave it a really good shake, then rinsed with old gas. Not much rust came out, so decided the problem wasn't too bad. Gave it a good clean & dried over the weekend, and now we're good to go.
     
  20. Dan Gardner

    Dan Gardner Well-Known Member Premium Member

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    Good news. From the photos that looked like one of the cleaner tanks you're ever going to find, so not surprising (to me) that not too much goo came out.

    Just play it safe and put an inline filter on there to make sure no chunks of anything try to get into the carbs.
     

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