Gas Tank Liner failure?

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SquareHead

SquareHead

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Sep 27, 2012
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Hi Folks,

I just finished rebuilding the forks on my 74 Cmdo. It ran great when I started the project. After I finished the fork rebuild, it was very hard to start and then wouldn't stay running. Lots of popping, misfiring, etc. Open the gas tank and looked inside. It appears that the liner is coming apart. There are chunks of brown plastic looking pieces. Some of the pieces are 1 inch long and clearly fit in the seams of the tank but have come loose. Looks like pieces of the liner clogged up my inline fuel filter.

Did Commando's come from the factory with a liner? My 1975 BMW did, but not sure about the Norton. If not, I assume the previous owner added liner material.

Any suggestions? I am at a loss at what to do next except send it out to a tank specialist. I have sent tanks to Moyer's in Pennsylvania, but I really don't want to do this if I don't have to. Plus, I really like the paint job on the tank.

Thanks,

Chris
 
I was afraid of that. I can only guess that the PO put sealer in the tank because there was a problem of sorts. Guess I should send it out and have it professionally inspected/repaired/fixed/sealed.

Any recommendations on tank repair companies?
 
If it's a stock '74 then it has a steel tank. You can load the tank with sharp things, like a box or 2 of drywall screws, and shake it until the liner comes off. Rinse with whatever you got.
 
maylar said:
If it's a stock '74 then it has a steel tank. You can load the tank with sharp things, like a box or 2 of drywall screws, and shake it until the liner comes off. Rinse with whatever you got.
Click to expand...

...although that doesn't FIX anything; you STILL need to have it repaired professionally which typically involves cutting out the bottom and sealing it PROPERLY, then re-sealing the bottom of the tank.

In other words, drain it from the filler neck and start letting it dry out 'till you choose who to send it to. Let THEM prep it properly.
 
I was finally able to talk to the previous owner. He sealed the tank in 2000 with POR 15. He said that the tank was in excellent shape, and he sealed it strictly for preventative reasons.

The tank looks very good inside except for the peeling liner.

So, all I really need to do is get the old liner out. I have read the MEK will remove the old liner. Is this true?

Thanks!
 
It is possible to purchase the POR 15 tank liner remover.Comes in a tin from the POR Distributors/sellers.I friend of mine used it recently to remove the liner from a New Fibreglass Ducati tank.He showed my the plastic shopping bag full of the pieces.Works well.
Brett
 
About nothing can resist acetone, brake fluid or ATF, especially warmed till explosive vapors. POR a decade ago was only for rust prevention not ethanol so that may of done it or just not that good of prep and application in your tank. If ya are lazy like ole Fla. boys ya can use lye to chemical boil to raw metal w/o much bother to put objects tank. There are a few new age 2 part coatings to recoat with so very few if any I've head of had to open up a steel tank.
 
I can't help to wonder if "corn gas" was the cause for this failure? So far it has destroyed the fuel lines on my weed wacker and leaf blower and I am holding it responsible for trashing the power valves in two H-D carbs. I only run Sunoco 110 in the Norton as I fear a total meltdown of my FG tank, even though it is sealed. My '68 JD lawn tractor won't run on the crap. I have to cut the corn gas with 110 to be able to mow the lawn!

Tom
 
Corn sqeezin's in gasoline is not quite infamous and many engine makers of equipment both advice and cancel warantee if feed ethanol. Our engines and carbs can stand it fine but not much else unless upgraded for it. Who knows what else gets put in with badly distilled ethanol. Another reason I think of this hobby as a manhood tester, partly d/t how much ya might have to endure that is not your fault.

We've a Sunooco station in city 112 octane at pump but 116 available there too.
Agricultural gas don't have booze in it but can't store much in city's. I just got 100 gal in over head tank with stabilizer and often top off me or Wesley or just add enough to make it to a station.

Ya know they sell boze in i think poly carbinate jugs, so maybe heat tank and pour a melt in to permanently fix it. I'm going to risk Peel thickly Caswelled coated tank but unless long travel not much booze in it.
 
Okay, guys, I bought a gallon of MEK and put it in my gas tank along with two handfuls of drywall screws. It's been in there for several days, now. A couple of times per day, I agitate the tank and slosh the liquid and screws around. I have it sealed tight when I agitate, but open the rubber stopper a bit so I don't build up pressure and damage the tank.

How long should I let the MEK sit in the tank? Would a week be long enough?
 
My tank was new, but had some light rust inside and had some light fabrication done to it, so I just kept rinsing till it ran clean. I used some paint filters so I could reuse the solvent. Then I rinsed it with acetone several times. FYI
 
It worked well. However, it took 10 or 15 rinses and lots of shaking with screws, nuts, etc. It was a lot of work. But, in my case, the liner was very thick at the bottom of the tank. Maybe 1/2 inch thick!

Be careful with the MEK. It's very toxic and dangerous to breathe. I did all of my work outside...
 
SquareHead said:
I was afraid of that. I can only guess that the PO put sealer in the tank because there was a problem of sorts. Guess I should send it out and have it professionally inspected/repaired/fixed/sealed.

Any recommendations on tank repair companies?
Click to expand...


http://www.gastankrenu.com/index.htm

Try these guys. I had two painted tanks done with no issues. They DO need to know you want to keep your paint.
 
I hope you are able to remove the old liner without screwing up the paint job around the fill spout. If you are lucky enough to do this Redkote is a good liner for metal tanks that have oxidized under the old coating, but if the tank is smooth and clean, no coating is necessary just dry it real good. Redkote is available at O'Reillys if you have them nearby.
 
If it was that thick, I don't think that's a bad rap on POR 15 but on the installer. I've had POR 15 in a Triumph steal tank for almost 12 years, its had 10% ethanol gas in it everyday since I did it and absolutely no deterioration.
Ya gotta follow the instructions is all.
 
SquareHead said:
Be careful with the MEK. It's very toxic and dangerous to breathe. I did all of my work outside...
Click to expand...
Yep, that stuff is real bad s%#T.

For tank sealer I like Redkote.
JUG
 
I hate ethanol....Keep it for food. Your pork chop will be cheaper and you will get 10% better gas mileage on straight gas.
Damn the EPA Gangreen loonietoons. :cry:
CNN
 
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