Draining the fuel tank

I have a bunch of crud in the bottom of my VF500F fuel tank & am trying to flush it all out. The crud keeps clogging the petcock screen (the screen tube inside the tank) & turning the tank upside down doesn't work because of the inch tall lip inside the filler hole.

My question:

How the hell do you get 100% of the fuel out of the tank? How do you guys flush out your fuel tanks?

Is the internal (inside the tank) petcock screen removable?

I have breathed enough gasoline fumes to fill the Goodyear blimp & I'm sick of it. There has to be a better way........

 

I'm not too sure how easy it would be to do, but I'd remove the petcock to clean it and the gauge sensor/any other equipment, put in some good degreaser or solvent that wont ruin the paint on the outside, then flush it out good.

Edit: This is assuming you mean some sort of buildup, not rust

 

what kind of crud is in it? if its rust then theres a relatively easy way to get rid of it

 

Remove the petcock and go from there.

 

Even with the Petcock removed it's difficult to get all of the fuel out.

When I cleaned out my tank I used a small hand pump and clear tube to siphon out the gas. I flipped the tank upside down and angled it back so the fuel sat in a nice flat spot in the tank, making it easier to reach all the fuel.

...I then used a telescoping magnet to pickup any loose rust.

 

Thanks to all.

I have been pouring in a little bit of fuel, pressurizing the tank through the petcock, & covering the filler hole with my hand to halfway seal the tank so the pressure will push the dirt up the outlet hose. My outlet hose is fed down into the front end of the tank with the tank tipped nose down. I have run about a gallon of gas (1/2 quart at a time) through the tank & still get a little bit of crap (enough to keep me trying) in my catch can.

At first I was getting muddy water & black dirt, but now I just see small spots of the black dirt. I have looked down in the tank with a flashlight & did not see any rust at all nor have I seen any rust in my catch can.

You ain't kiddin' brother!

I guess there really isn't a better way.

FLUSH ON!

 

lol....I feel your pain. It took me awhile to flush out the tank...and even afterwards I decided to install 2 little fuel filters before the carbs.

 

Yes, definitely going with 2 filters. I need one of those old school sediment bowls from an old tractor! I might try to get one of those stone filters, they seem to catch everything. Rigged up a better plumbing arrangement to reduce my gasoline fume intake. Put another gallon through it, it's getting cleaner but not 100% clean yet. I still can't believe the bike ran so good with such crap for fuel. My 75' Shovel would have probably set the air cleaner element on fire if it's fuel was that dirty.

 

Gotta do lots of SHAKING while draining to flush out crap.

Might be time to coat the tank, eh ??

 

I all ways used a rag on a string to get all the gas out. wear fuel resistant gloves and wring it out, repeat until all most completely dry then rinse with a fast drying solvent. I use naptha. I then use a garden hose to rinse for a LONG time, some times over night you'd be surprised how much crud will come out that way. If you have a good bit of rust I've had good luck with some thing called blue lightning. I've also used the same stuff on parkerised gun parts that have rust, it eats the rust and leaves the parkerise, it'll eat gun blue off thought.

 

When I did my tank on my 93 because of rust, I didn't worry about getting all the fuel out. I got as much out as possible, then put BB's in with almost boiling hot water and shook until the cows came home. Drained water, repeated 9 times. This got out about 95% of the rust. Then I put 5 gallons of white vinegar in and let sit for 48 hours. Drained and rinsed with water. After that I used alcohol and swished it around and let air dry. After that I coated the inside. I did this last year and haven't had a problem since. I've changed the filter since then with nothing showing in it. This was just my experience, good luck.

 

The VF500 tank has soo many small space and crevices that I would recommend against putting BB's in there. You'd have a hell of a time getting them all out.

....and regarding coating. I had my VF500 tank coated and it didn't reach all the crevices and spaces in the tank...and those small spots are where the tank tends to rust.

 

+1 on holding off on using BBs.

I recently completed a tank restoration. I would recommend sealing the tank after you are finished. Caswell makes a great product (Caswell Inc. - Epoxy Gas Tank Sealer)

For reference here is a photo of a tank that has been cutaway and a sketch of the problematic 'shelf' located on the lower corners:

 

Very cool picture. I wanted to do that to my tank a couple of times!

If I suspect rust, how should I go about dealing with it?

From what I can tell, the internal (inside the damned tank) petcock screen is not removable. If I poured some sealer goo in my tank it would coat that internal screen & never flow fuel again. It appears that if a guy wanted to pour in a coating goo, he would have to get that stupid screen out of the tank first.

The internal petcock screen (what is it really called?) is sock shaped from what I can tell, with the petcock valve "on" tube protruding up from the open bottom end. I have seen dudes tear those screens out from the inside because they clog up on dirt bikes but I don't really want to do that. Life sure would be easier if it were gone though.....

 

Do you mean this fella?

 

My '86 didn't have the Filter Screen sock over the tube....nor did it have the little screens/strainers inside the strainer cap.

I can only assume the previous owners removed them due to the rusty tank.

 

Yes! That filter screen right there!
Ok, so it just pulls out of the tank?
It looks like it should have come out with the petcock assembly. Hope I can get it out without damaging it.

I can definitely understand why someone would remove that thing but I don't want to grind the guts out of my petcock valve on debris so I will just pull mine & clean it.

Awesome. Thanks for the illustration.

 

Nice, thanks for the pic. I took my screen outta the tank, but ripped it,so gonna grab a new one, or a replacement. Mine was rusty, so I tossed about 8 washers in, which turned out to be a sucky idea. I'll get as many as I can with my telescoping magnets, and at some point, I'll probably give up and put some of my crazy strong magnets in strategic places. Will do that anyways, to grab rust flakes.