Rust Never Sleeps

A few years ago, I got a $21.50 GPz tank on eBay. It was in terrible shape, all rusty inside, tons of Bondo on the outside. I stripped it down to the bare metal so I could see what I had to work with, cleaned it out with muriatic acid, then neutralized the acid with water & baking soda, braze welded a couple pinholes along the bottom seam, then pushed about a quart of fresh Bondo into the dents and painted it. I would have Kreemed it or used some POR-15 tank sealer, but I was broke at that stage of the process, so I didn't. I should have, but I didn't.

Fast forward to actually using the tank. I put a couple hundred miles on it without incident, but last weekend I decided to take advantage of the beautiful weather and go ride around Lake Stanley Draper.



On the way up there, the bike started cutting out like it was running out of gas... I downshifted and gave it some throttle, putting it on the main jets, and it cleared up. I shifted back into 5th and it ran okay. I made it to the lake and went around the twisty road once, but on the second time it started cutting out and it just got worse and worse until the bike seemed to be running on only one cylinder... then it ground to a halt.

Yard sale.





Oh, the shame!



The culprit:







After a thorough douching of the carbs, I proceeded to derust the tank... again. After some googling I found out that vinegar is good for removing rust, and it's even better if it's combined with heat and salt. I had a couple jugs of old vinegar, and since vinegar gets stronger with age, this was ideal. I dumped about a cup of salt into the tank and ran the vinegar through the coffee maker (it was time to do that, anyway), then poured the boiling vinegar into the tank.





I drained all the vinegar and washed out the salt, rinsed the tank with hot water and about half a box of baking soda, then more clean water, then set the tank on top of a heater with a hair drier in the filler hole for a couple hours:



I went back to check on the tank later, and it was bone dry... but when I picked up the tank I heard this "sssshhhhhh" as huge amounts of rust moved around inside. :x

Time to get mechanical on it's ass.



I dumped several partial boxes of drywall screws in the tank, then spent about an hour rocking it back and forth.





I was able to get a vacuum hose inside and suck out most of the rust, then repeated the rinse and dry procedure. The tank now has the "normal" amount of rust you'd expect to see inside a gas tank.

Looking around inside, I found where the tank was leaking behind where one of the logo badges used to mount, which has caused a blister to form on the outside of the tank.





Gotta love that JB Weld!



Cleaned up the petcock:





Since rust was obviously getting through the fuel filter, and I'm a broke joke and cheap to boot, I dug around in Ye Olde Junke Pile and found another filter.



Belt + suspenders, right?

I rode the bike maybe 75 miles yesterday and it did just fine! No hesitation whatsoever, revs even easier than it did before the breakdown, sounds suuuuuuper sweet in full song!

This winter, when it's too cold to ride, I'll fix the paint on the right side where it leaked and blistered, plus I'll apply some tank sealer.

I've read(maybe on this forum) the way this guy de-rusted his tank was to pad the inside of the family clothes dryer with blankets so the tank won't bang around,put nuts,screws and BB's in the tank and run the dryer on no heat for several hours. Sure, it'll make noise but the rust will be scraped away.

He then used POR-15 as a sealer after he washed the loose rust away and has had no problems since.

guitargeek, glad things have turned out good for ya. I just have to say I love your story/pictorial essays!!

The red frame looks cool with the black tank and stuff. I never thought of it.

Oh believe me, I would have put this tank in the drier if it'd fit!

Big tank + small drier = upper body workout.

i have never heard about that vinegar trick that's one i'll have to use in the future because i'm basicly a cheap bastard at heart too. it sure looks like it works well. see if you don't learn something new every day you either know it all or your dead . thanks for the tip i like it.

Hey GG,

Sounds like you had an extreme case of rust. If you've got pinholes near the tank badges imagine what the bottom of the tank looks like.

I'm not much of a supporter of tank lining but I'm willing to admit that that the inside surface of a rusted tank probably amounts to about an acre of microscopic surface more than a new tank has.

I've always suggested tank lining in the case of a leaking tank.

Let me explain one reason why I don't like tank lining:

I picked up a 1974 W3. It appeared to have a rusty tank, it was already equipped with in line filters. I acid washed that tank, I tumbled that tank, I swore at that tank!!! I finally realized that the Damn rust was underneath a previous layer of epoxy.

The lesson I've learned is that once your tank has rusted it's predisposed to rerust again. The only way to avoid the problem is to keep the tank full any time you're not riding, Or to, Gawd Forbid, line it.

KZCSI

MFolks wrote:

I've read(maybe on this forum) the way this guy de-rusted his tank was to pad the inside of the family clothes dryer with blankets so the tank won't bang around,put nuts,screws and BB's in the tank and run the dryer on no heat for several hours. Sure, it'll make noise but the rust will be scraped away.

He then used POR-15 as a sealer after he washed the loose rust away and has had no problems since.

I did all that, but not the sealer. I'm not a sealer guy.

After the dryer, I used water, then phosphoric acid for a rinse, then water again and an oil coat. Clean and shiney inside after a year..

My bro always did the dryer n' BB's and used vinegar. "Douche the tank" And I'm surprised no one has said of the thread title "Great Album"...Neil Young and Crazy Horse

Locozuna wrote:

Great Album

Indeed! I wore that cassette out, back in the 80s. A decade later it was Ragged Glory at high volume, over and over and over.