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Rust in the gas tank

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I have a 1970 CL175E that is just about ready to roll but I have to deal with the rust inside the tank first. I tried navel jelly but I let it dry after I rinsed it and it was covered in rust in about 30 minutes. I don't know why I didn't see that coming. :thumbsup: I have heard of using muriatic acid but would prefer to leave that stuff alone. The kreen kit I have had bad luck with. I thought about sand blasting it but I don't think I could reach the bottom of the tank. So, that leaves me to boiling it out at a radiator shop I guess? I am concerned with the heat of the water taking off the paint on the outside of the tank. It has the original paint on it and it is in great condition. Has anyone tried this method? I called around and the shops I spoke with said that it could be a problem and they $75 to do it. Any thoughts? Any other methods I am missing? Thanks. Oh, sorry the one shop that wanted $75 said that he actually acid etches it then coats it. Maybe I am being cheap i just didn't want to pay that price but right now it looks like the only viable option.

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I had very good luck with the kreem product on my hodaka. That tank was very rusty. Buy the kit and take your time prepping with part 1 and 2. After the kreem was in i was rotating it religiously for a 10 hour period of time

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Do you have a Smart and Final store in your town? If so go to their cleaning supplies isle and find a product labeled as "Pink toilet bowl cleaner" Its cheap less than $10 a gallon. It is a slightly diluted form of muriatic acid. I cleaned the tank on my 68 CL90 (which was very rusty) and it came out great.

Fill the tank about 1/4 full and put the cap on. Slosh cleaner around inside for 30-60 minutes (or however long it takes) Empty out and wash out with water. Then spray inside of tank with a large amount of WD40 and dump out excess. Continue to do so until all water is out of tank. I did this over 3 years ago and have had no further occurrences of rust.

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I assume the toilet cleaner in not too enviro friendly so where do I dispose of it? I may give the kreen another shot too. I really don't want to spend $75 on the tank.

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I just looked up the smart & final and we have a cash & carry which looks to be the same place or under the same ownership. I'll check after work to see if they have that. You said 30 to 60 minutes!? Do I need to worry about the paint on the outside? I assume so, just drain it out of the petcock?

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Don't worry, its not overly strong. It took the rust out great, but did not damage the paint. I wore light rubber gloves and just turned the tank over and dumped it out the fuel filler. Don't forget toilet bowl cleaner is designed to be flushed down the drain so it is water soluble.

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A few months ago I picked up a CM400 that had been parked for 22 years. The tank was pretty rusty. It was more of a surface rust than a really deep half way through the metal kind of rust. I removed it from the bike and put about 2 cups of 1/4 to 1/2 inch gravel. It was a crushed rock type that was angular, not round pea gravel. I put in a few cups of soapy water. I then shook it around until my arms were about to fall off. I changed the water a few times. That got about 95% of the rust out. I reinstalled it with a fuel filter, and it's been working great. So far I've put 2000 miles on it. At first some crud got through and held the float valves open from time to time. That can be cleared by opend the fuel drain until the gas runs out, then open up the petcock. It will flush the crap out.

A box of 1/4 inch nuts works better than the gravel, but I had the gravel handy.

I don't really like the Kreem type products. Eventually it comes off the tank and then the problems are even worse than the rust.

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Well I went to Cash and carry and couldn't find the product. So I then went to Lowes and bought a product called Navel Jelly rust disovler. I put nearly the entire bottle in the tank and shook it all around and then let it sit turning every 10 minutes or so. I left it in there about 45 minutes total. Rinsed it out with water real good blew some commpressed air through it then hit it with some WD. After that I let it dry out and filled it up with gas. :thumbsup: So far so good. I also installed a fuel filter on each on the carb lines to catch anything that may comes through. Thanks for the help guys. :ride:

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It isn't spotless, but it is clean enough that I am not too worried about it especially with the filters. 10x better than before.

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took my 75 xl125 tank to a raidator shop they cleaned and epoxied[sp] it 15 yrs ago

still going ,no rust

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