Cleaning fuel tank

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,

 

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.

 

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.

 

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.

 

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

 

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.

 

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.

 

Thanks, I’ll “look it up”

 

For the extra rusty tank...

 

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.

 

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.

 

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.

 

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

 

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.

 

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,

 

Thank you!

 

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?

 

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.

 

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.

 

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.

 

Flushing a gas tank sounds easy, but so far not easy for me, and advise or tips appreciated! I have the tank off the bike, it’s a multi-year rebuild project as these this tend to become…. There was a small amount of gas still in the tank, sloshing it around it seemed like maybe a litre or so. I thought I could just invert the tank and pour it out the filler cap but no luck as there is a lip there that traps the gas and prevents it from coming out. So I opened the petcock over a pail and tried to drain it that way… not very efficient… lots of rocking and tilting the tanks around and still only about 1/2 came out. So I removed the petcock and had better results, still lots of rocking and tilting required, and the gas tended to follow the outside shape of the bottom of the tank, some went into the bucket but more went all over my hands and the ground. Finally got virtually all out, small amount left that should evaporate off (outside) over the next day or so. A inspection through the filler shows a few flakes (rust?) but it’s really hard to see much inside I guess due to the filler being offset from the ridge that fits over the frame. So 1) I’m not really sure of its condition, and 2) I’m not sure how I would ever get a cleaning solution out if I put something in there given my trouble getting the residual gas out…. Any tips or suggestions on this? Much appreciated!

 

Once the smell of fuel has gone you can use a flexible borescope taped to a piece of wire to see the condition of the tank. The cheap ones that plug into a lap top or mobile phone should suffice. That is how I checked the inside of my 900f tank. Make sure there are no fumes. Then you can decide if you need a rust remover like Evaporust.

 

Check this video to see how I cleaned my tank which was quite rusty inside. I’ve done this to a few tanks and it works great and is also very cheap.
Hope this helps.

 

Thanks, nice video!