Derusting Your Gas Tank

[MJSantos]

I was given a 1983 GL1100 I that was last riden by my uncle in 1991. Well the first order of business was to start going through it. The gas tank still had gas if you want to call it that. So removal of the tank was necessary. I poured 3/4 of a cup of rust out of it. Couldn't even see the pickup tubes or screens. Doing some research for a new tank was sticker shock over $1000.00 and I really didn't want to use acids in a tank this old. Buying a used tank was dealing with maybe more problems. I came across an electrolysis method the I was willing to try before going the acid route. There are severl websites on this subject this was the most informative, http://users.eastlink.ca/~pspencer/nsae ... ml#special.
The principle behind this is the current causes the rust to release from the base metal and redeposit on the sacrifical anode. It doesn't hurt the base metal. What you do is go to the market and buy a box of Arm n Hammer Washing Soda, (NOT Baking Soda). According to the article you can also use PH Plus, swimming pool chemical if you can't get a hold of Arm n Hammer. Mix 1/2 cup to 5 gallons of water. Pour the mixture into the tank. The only parts that have to be removed are the sending unit and the petcock since there's other types of metals beside steel in them. Block the pickup tube holes. Fabricate an anode from a piece of steel coat hanger and this is suspended into the tank in the solution. Do not allow it to touch the metal of the tank. Connect a battery charger, positive to the anode and negative to the tank itself. I had to put a light bulb in series with the anode to reduce the current so as not to overdrive the charger, 2 amps or less will do it. I ran mine for about a week on and off and then dumped it out.Not to worry your dumping out soapy water with rust in it just don't dump it on the driveway or concrete you'll get rust stains! What a shock when I looked inside and saw the bright metal and even the pickup tubes glistened. Get the fresh metal under cover as soon as you can to keep "Flash" rust from forming. I just filled the tank with gas.

[WingForChrist]

I tried another method. I did not want to go to trouble of pulling a tank or playing with electric. I went out and bought 5 gal of vinegar. I tested it on the gas cap before using it on the tank. Drained the tank of gas. filled the tank with vinegar for 2 days and did not pull the float out. took the drain plug out and then rinsed with baking soda to kill the acid. rinsed out and looks like new. I then blew air in it to dry quickly and put in gas, stabilzer and Mystery motor oil(to keep from rerusting). Tank came out almost like new.

[AMSOILER]

Thanks Gentlemen, I am going to try the Vinegar route myself since this looks to be the least amount of trouble.

[MJSantos]

Looked at the vinegar solution myself but since I was going thru it, the tank was coming off anyway. You're right it was a hassle pulling the tank. I think it's worse than the carbs coming out. Definite "Right's of Passage". I think either way is still a safer solution than acid treatments with tanks this old.

[WingForChrist]

When checking into ways to clean a tank, I talked to the local Honda dealer and a guy in the shop said you would be suprised what all they use vinegar for to clean.

[WingAdmin]

I've heard of using Coca Cola, because of the phosphoric acid. I don't know that I would try it myself, but I suppose it makes sense.

[MJSantos]

I would be leary of Coke. Be my luck that some wouldn't be cleaned out then I can see all kinds of carb issues.

[MJSantos]

Question for WingForChrist, you said you pulled the drain plug? Maybe a change on the tank configurations but I didn't see one on the "83" Gl. I guess leaving the tank on the bike woud require using a wet/dry vac to empty it.

[WingForChrist]

MJ I am not sure. On the 83'. Mine was a 77. on the right hand side of the tank there was a bolt, I think it was a 17 or 19mm head size, that will let you drain the tank. I don't know if it is the same on the other models. I checked the parts manuals off this site for the GL1000 75-77, on page 111- part number 25 says drain plug. I also pulled the parts manual gl1100 1980 to 1982. Block F20 or page 113 in adobe shows a part number 21 but it is saying a pan screw and not a drain plug. So without seeing it I would say that it might not have one. I did find one site if you do a google search under
(Don't get "kreemed") it should pop right up. the owner of the site does not like to be quoted anywere, but site has 1100 listed under his tech tips and says :At a minimum, drain or siphon all the old fuel out. The drain plug is located near the rear master cylinder.
If this is not accurate,A dry vac might work if you have a hose to fit in there and get it all out. problem I might see if you cannot get it all out it might start rusting again while getting it all out.


Also I heard of the coke working and other things that could work. I would suggest trying an experiment like I did first. I took the gas cap, couple rusty bolt and setup some glass jars in the kitchen. I let them set for 2 days. Vinager seemed to work the best. I also thought that coke would be sticky and i also added diet coke in my experiment so it would not have the sugar content Still vinager worked best for me. I suggest do an experiment like yourself. it will only put you out for 2 days but will give you confidence on what you are about to undertake and what to expect.

[panthernut9]

Going through and derusting my tank now. I regret not taking pictures of the before and after. The tank was very solid as far as the steel is concerned. Completely rusted tank a really thin layer over the entire inside. I looked in to a new tank and was amazed at the price. Checked around and could get a used one for about $200, so I thought I would try the vinegar. Wow it has removed 95% of the rust from inside the tank. Completely amazed at how good it worked. No leaks in the tank. The problem now is there are 2 hard lines inside the tank that are tack welded from the inside. They have a couple of screens on them to prevent the chunks from getting through, but they are completely rusted. I was able to use a hand syphon pump to pull some of the vinegar through the lines but it did not remove the rust on these screens. Went to OLE' harbor freight found some 12" wire brushes to try and reach the screens but can't get that rust off the screens. All in all the vinegar worked wonders on this old tank.

Thinking the next step is to probably punch out those rusted screens and just change the fuel filter often. Any ideas on this from any one?

Also what is the best way to coat, or line the tank after the derusting to prevent the rust build up again. I know that keeping the tank full from now on will benefit best but have been looking at how to coat the tank and find all kinds of things. A buddy of mine says just to keep the tank full and use the sta-bil and marvel mystery oil once in a while and all should be good. Any thoughts on this as well?

Probably looking at about a month still prior to the first ride. This weekend will consist of replacing the rear wheel bearings and cleaning and greasing the final drive and getting that ready for re-install. All thanks to the GREAT instructions here.

Got the bike down to just the frame, electrical, and front tire assembled. The rest is still in the process of being rejuvenated.

[MJSantos]

When it came down to the screens I filled the tubes from the petcock end with PB Blaster. Had to let it set then took welding wire off of my mig welder doubled it to make a rooter. Did the trick after awhile I shot about 90 PSI and they blew open.

[Victour78]

I think the PO filled the tank on my With gas to keep it from rusting.. worked great. no Rust. Lacquer Gum about 1/8 thick on everything inside..Tried Carb cleaner . No Help, Tried Brake cleaner no Help...Used the magic Chain.. all that done was tear up the screens... went and got ..Nasty Muratic Acid.. Help very littlle .. because the screens were damaged I used a fine cup brush on a 18" extension on my Drill motor...Helped a little.. Should have used the Electrolysis process long time ago.. I may still do that because it still don't look good... coated it with WD-40 so there is no new rust..
I can't believe that WD is so fantastic until I honed cylinders on a V8 sprayed and stuck in a corner.. One year later only dirt showed up on the bores...

[MJSantos]

If you try the electrolysis method run an insulated wire down the tubes from the petcock end with just the end exposed if you get it against the screen that will deliver the full current at that point. It might be just enough to draw the rust out of the screens on to the sacrificial anode. I suspended that anode down through the sending unit hole so it was close to the screens.

[herman230]

I have tried it all, but none of the products worked for me. My gas tank had so much rust in it the pickup tubes were rusted shut. I found a product called METAL RESCUE and It worked like a million bucks .I poured it in the tank and let it sit over night, the next day I checked and both tubes were open. I was so impressed I became dealer a for this product. IT REALLY WORKS GREAT......the inside of my tank and the screens look like new. You can purchase this product for $25.00 a gallon plus shipping. Just call 586 854 2093

[Tamirand2004]

WingForChrist or any of you that used the vinegar. I have some rust on my gas cap(minor pitting) can you use the vinegar without removing the gasket or is it better to remove? I am also getting a back fire when the bike is warmed up, usually after a quick decell then back on the throttle, but i have even had it scare the crap out of me when it does it when I have started it up warm. Any suggestions on where to start. The bike sat for about a year before I bought it. Didn't do it at first, started using Seafoam per suggestion of local bike shop and it still hasn't gone away but not any worse. could this be a rusty or plugged pickup issue?

[panthernut9]

WingForChrist or any of you that used the vinegar. I have some rust on my gas cap(minor pitting) can you use the vinegar without removing the gasket or is it better to remove? I am also getting a back fire when the bike is warmed up, usually after a quick decell then back on the throttle, but i have even had it scare the crap out of me when it does it when I have started it up warm. Any suggestions on where to start. The bike sat for about a year before I bought it. Didn't do it at first, started using Seafoam per suggestion of local bike shop and it still hasn't gone away but not any worse. could this be a rusty or plugged pickup issue?

I removed the seal from the cap dunno if vinegar affects rubbers in anyway but did not want to take the chance. I personally can not see the rust issue being a cause of the backfire. It would be some sort of timing issue, (possibly), it could also be that the fuel is running too much in to the piston after it has fired it is on the decompression stage and gas is not burned out, residual leftovers. Just a thought there sorry not much help, I can not diagnose issues I can only fix them after they have been diagnosed by a "real" mechanic.

[Tamirand2004]

Thanks Wing,

Sorry, didn't mean to make it sound like all one associated question lol

[larryakruse]

Hey, I don't mean to rain on anybody's parade but the best method I have found is to take the tank to a Radiator shop and let them acid dunk and then coat. It cost me $89.00 USD and the tank is better than new. The coating will not come off and because of it the tank will never rust again. The only draw back is I had to remove the screen filters from the main and reserve outlet pipes. They were rusted anyway so it was no big deal. I have built a bunch of bikes and Creamed more tanks than I can remember. Never again. 90 bucks is cheap compared to a new tank and the time to mess around with home remedies has surpassed fun by many miles. If you are in the New Orleans area send me a message and I will find the name of the shop I took the tank to. They are motorcycle friendly and that is always a plus.

[WingForChrist]

Sorry for the delay in reply but I soaked the gas cap too. that was one of the first things I did my test on. worked good. I cannot tell it did anything to the seal. I am a year into riding after doing the tank and looked in it the other day and don't have rust. I try to keep it full of gas and Mystery oil.

[KurtH]

These all look like good ideas. I just purchased a 1980 GL1100 for $400.00 (US) and the tank is in really bad shape. Has a lot of rust in it. I was able to drain the old fuel out by attaching a hose to the front flow valve. I got most of it out, but I can still see some down inside. I would like to remove the tank, but I am having one heck of a time trying to figure it out. This is my first bike. I removed the false tank, then removed the retaining bar that goes over the top of the tank, removed the rear bolt and then I'm stuck. Not sure what is left. Any ideas? I have been scouring the internet for a way to get it out. Any help is much appreciated!

[MJSantos]

Removing the tank is a baptism under fire. The tank comes out the rear of the bike. You have to remove the rear tire, fender and shocks. Then there's a support arm for the rear caliper that will get in the way. I just took it loose. remove the petcock to prevent breaking it. Thetank will come out with a little persuasion. you already are half way by removing the seat and the one bolt holding the tank.

[KurtH]

Thank you, I will give that a try. I am not 100% sure on how to remove the rear tire, but I'm sure I will figure it out

[fishnquest]

These all look like good ideas. I just purchased a 1980 GL1100 for $400.00 (US) and the tank is in really bad shape. Has a lot of rust in it. I was able to drain the old fuel out by attaching a hose to the front flow valve. I got most of it out, but I can still see some down inside. I would like to remove the tank, but I am having one heck of a time trying to figure it out. This is my first bike. I removed the false tank, then removed the retaining bar that goes over the top of the tank, removed the rear bolt and then I'm stuck. Not sure what is left. Any ideas? I have been scouring the internet for a way to get it out. Any help is much appreciated!

I have started a restoration project on a 1981 gl1100 for my son. I removed the gas tank by first removing the rear wheel. Surprisingly it was not difficult at all and done in about 30 minutes. After I got the rear wheel off, the tanks slides out the back. The instructions to remove the rear wheel are in the diy articles. This is gonna be way easier than my 67 camaro rebuild! This site is a lifesaver. Good luck.

[WingForChrist]

I used vinegar because on the 75-79 models there is a drain plug on the gas tank , therefore you do not have to pull the gas tank off for this process. I think on the later models over 80 the plug is eliminated and you would need to remove the tank and if you are going to pull the wheel here is a good solution i came across.

/forum/viewt ... f=3&t=3094

http://www.cyclepsycho.com/goldwing/gltanks.html

[fishnquest]

Thank you for the links. Its awesome to see the inside of a tank, pickup screens and all!