Gas tank horror story~

Here's a couple "Before pics"




Using some unique plugs to seal the tank:

Found a great expanding plug at a hot tub place that has a wing_nut to fatten it up and perfectly seal the filler hole.



Lucked out and had a wine bottle stopper that fit the petcock perfectly.



What I needed was something to fit the oval hole beside the petcock that accomodates the fuel sensor. Being an oval shape it was very awkward. A friend lent me a device called a "Chubby" that is a rubber bladder with an air valve on it. Pumped it up to 60 PSI for an amazing seal.




My buddy found it at a garage sale and neither he or I had ever seen one like it... Cool little tool. Here's the box it came in.




Currently treating the inside of the tank with 2 gallons of fresh vinegar... dumped out the first batch after 6 days and the difference inside is amazing! l don't own a pressure washer but just used my garden hose to rinse it out. tons more paper thin stuff came out revealing very nice silvery metal surfaces... it really looks good but some thin remains of the coating are still apparent (90% gone though) It's the kind of residue that you can remove with your finger.

I put in 2 fresh gallons in and plan on giving it a few more days. then using a pressure washer and a powerful air compressor. Hopefully that'll blow all the crap out.

If all goes well does anyone know a treatment that treats or etches metal to prevent corrosion? I suspect the vinegar being a mild acid may well remove the galvanizing and make the metal prone to rusting.

I think the vinegar treatment is an amazing process... Very effective and unlike much more powerful acids and other caustic chemicals your doesn't put your paint in jeopardy.

Will post pics of the tank when it's done.
W

Check eastwood.com,theyre a little pricey but they have everything you could imagine for metal

I used Oxalic Acid to do a spare tank for my bike - it's available in powder form at ACE Hardware, in their paint sections, for removing rust stains, and staining wood - it's cheap, use about 1 cup of the powder in a half gallon of warm water. Agitate the tank vigorously with the dissolved solution inside - do that several times in a half hour or so, then pour out the solution to check results - might take 2 applications - when satisfied with results, rinse thoroughly with clean water, and if possible, blow warm air thru the tank- a hair dryer or vacuum cleaner/shop vacuum in the "blow" setup will work well. The Oxalic Acid will not harm anything but rust, so no worries about paint, etc.

Here's what my tank looked like inside after treatment - and it was worse than the the one pictured further above - this is a re-post from another board:

This may be posted elsewhere, But I haven't seen anything other than passing comments as to use of Oxalic Acid to clean the insides of rusted bike fuel tanks - so here's MY version!

The Oxalic acid is extremely easy to use, is pretty harmless to anything but rust - which it DOES attack with a vengeance!

The stuff is commonly available in a powder form at hardware stores, is sold as a wood washing/staining treatment or rust and stain removal product, and is pretty cheap - I used a single container as seen in the pic below, and it was enough to completely treat and clean my KZ1100 LTD tank - this is a 12 oz container:

I had just received a duplicate tank for my bike, to use as a base for a custom paint job - these tanks for older bikes like mine are quite rare - and nearly impossible to find in good condition - OR at anything other than astronomical prices - they commonly go for $200 on up WHEN/IF you can even FIND them! SO, I was quite lucky to locate the one I have at a VERY attractive price, NOT all beat up and not TOO badly rusted inside:

BUT, while not what I would call REAL bad, there WAS a full coating of surface rust all thru the insides of that tank - not the multi-layered, flaking off type, but enough that I sure wouldn't want to use it the way it was!

I masked off the petcock and fuel level float mounting holes, fabricated a plug to close off the fuel cap area - and then mixed up half the container of the Oxalic Acid powder in about a half-gallon of very warm water - then poured it into the tank. I agitated and rotated the tank to cover all the insides - and repeated all that operation frequently for about a half hour - then emptied out the acid solution, and flushed out the tank - it looked VERY good.

BUT, there WERE still a few areas I could see that still showed traces of remaining rust - and since I really had no use for the other half of the remaining Oxalic Acid powder, I went ahead and did another treatment - but left the acid solution in for about a full hour this time - again repeatedly shaking and rotating the tank to cover all surfaces.

After again emptying the acid solution, and rinsing out the tank, I used my compressor to blow the insides of the tank pretty dry, and then put my heat gun at the fuel inlet, and with it set on a low heat setting, let it blow warm dry air thru the tank and out the petcock and fuel level openings until completely dry.

The results?

Virtually ALL the visible inside surfaces and seams look as pictured...

NOT bad for under $10 - and a couple hours work!, eh?

Hi 300kph, sorry to hear your crappy luck, but happy birthday anyway. I really like this white vinegar trick for cleaning the tank. I just went through this (tank bs) @ 4 months ago on one of my 77KZ1000 tanks.... it was on my higher end bike also :sick: . I was in the same boat, I had the tank painted years ago but forgot to drain it completely, what a freaking MESS!!! I had a brand new Pingle fuel vale on it also... took hours just to clean out the valve.

Anyway I de-rusted my gas tank and used Muratic acid in my tank with large bolts and fender washers but I masked the outside of the tank using house construction vapour barrier and duc tape to protect the paint. I also used rubber plugs I bought at my local hardware store for the holes, they were sorta "off-white" in color and these puppies are the most DURABLE product I've ever come across in anything... you can't cut (Olfa Knife new blade), burn (Only propane, but full blast), or degrade this rubber no matter how hard you try, with normal shop tools anyway. I tried to find out what this stuff is made out of but had no luck, though I'd mention it anyway.

What a BRUTAL product muratic acid is to use (I diluted it also using water) I dammed near passed out when I accidently got a solid whiff of it. I rinsed the tank out after repeated applications of muratic acid using the garden hose but it flash rusted super quick... I don't think there is a way to get around this if you have better luck let us know. I think if you fill the tank to the top with gas as quick as you can after rinsing it might be your best option... I'm confident a small amout of flash rust will not hurt your carbs. I just installed a set of brand new 36mm RS Flat slides and the bowls have yet to see fuel (so I'm a bit paranoid now about clean fuel) but I will be rechecking the tank for signs of rust like crazy now. If I have to redo it I'll be using white vinegar in the future.


On another note... I thought I was the slowest project on this forum (27 years, almost done) but WOW 32!

Happy Trails, Doug

After cleaning the tank interior, you can coat the inside with lead by shaking it stuffed with lead pellets/bullets (like from a shot gun). This will act as a barrier to keep rust at bay.