[Robert Garey]

Hi. I want to clean my gas tank. I'm swapping out my bendix carb for a mikuni on my early xlch. I need to change the petcock too to accommodate the new configuration. And while I'm doing this it provides a good opportunity to give the tank a good cleaning. Suggestions and info as to cleaning a tank? I don't need an extensive process because I've been currently running the tank, but I did notice some fine gritty crud on the pingle petcock when I removed it. Thanks!

 

[doc308]

If it's not too corroded, an old fashioned way to get the rust out is to put a lot of nuts and bolts into the tank and roll them around and around. If I recall correctly, in the past, I've then swished vinegar and water inside of the tank also. Then flush it out real well with kerosene over and over to get all of the remaining crud out. You can flush it with water too but you'll need to immediately put fuel in the tank to prevent new rust from forming. I haven't done this in many years and there may be better ways of doing it today.

 

[magnum45pete]

if you want it clean insides, I found the best way was to.......
put a 1 to 2lbs of sheet rock nails in it, then a pint or two of Kerosine, seal the cap and outlet well .....
then wrap it in old blankets and some old seat foam, put the whole lot into a portable electric cement mixer for an hour on slow,
then remove the nails with a magnet if they don't all shake out,
then flush it out with fresh kerosine till it comes out clean, and ya done,... perfectly clean inside
once the tank is off, it shouldn't take more than an hour before ya bolting it back on the bike

 

[Ratso]

There are probly dozens of tank-cleaning (and -sealing) threads in the JJ archives, with hundreds of opinions (many of them valid). That's if you can get the Search Machine to behave in a helpful fashion, which: good luck.

Pete's advice is as good as you're likely to find, except I imagine that relatively few of us have access to a cement mixer! Others have suggested blanket-wrapping the tank until it barely squeezes into a clothes dryer. (Even I have one of those.)

My own best success took some time: most of two weeks, if I remember right. But no dryer was involved, only topping up the tank with dilute white vinegar (it's very cheap); parking it in a secluded corner of the garage; shaking it good, semi-daily; and changing out the vinegar mixture every few days until you see nothing but bright metal inside. It works well, it doesn't eat the metal, and you can dispose of the rusty vinegar w/o abusing the environment or potentially blowing up your shop.

 

[magnum45pete]

Pete's advice is as good as you're likely to find, except I imagine that relatively few of us have access to a cement mixer! Others have suggested blanket-wrapping the tank until it barely squeezes into a clothes dryer. (Even I have one of those.)

ya quite right Ratso, not eveyone has one, but I was lucky as a buddy had been building a brick wall at his house and had a smallish electric one on hire, so used it after he'd cleaned it out before he took it back to the hire shop, but a lot of friends are in the construction business and had a few offers of a loan, but theirs were all real BIG industrial ones ya need a trailer to move..

 

[Elektron]

I agree w/Ratso, vinegar is useful. You can use cleaning vinegar which is available at Home Depot in various concentrations. I like 6% but you can get it much stronger. Dilute it, I suggest if you buy 10-20-30%. I haven't seen the need to change the vinegar, I've used the same vinegar on more-than one job. I've also used solid bricks to lessen the amount of vinegar needed. I use a plastic bin to contain the liquid, and place the piece into the fluid covering it, or if the piece is larger than the level of vinegar, after the vinegar has worked to remove rust on the one side, I turn it over, to immerse the other side.

Here's an example of a body part being cleaned.

'Two 'after' pics.

This is the 'before' pic.

After about half the time in the vinegar.

I disagree that vinegar is 'safe in all cases.' Here's a pic of a fuel level sender mechanism, I believe it's potmetal, and much of the potmetal was dissolved in the 6% vinegar while the steel body panel (above) was unharmed.

Here's a SBC valve cover, steel, being soaked. It was soaked upside-down. You can see the non-immersed part, the flange and about an inch above it. The shiny-chrome top 3/4 of the valve cover was soaked in 6% cleaning vinegar for a 24 hour period. Quite a difference.

Here are some tools before/after.