cleaning the inside of a gas tank

[Romeo]

Does anyone have any ideas on how to clean the inside of a gas tank? I recently acquired a 1975 cb550 and the tank has quite a bit of varnish down in the corners. I seem to remember something about using some sort of small sharp objects as agitators. Any ideas, suggestions would be appreciated.

[tybme]

There are a couple ways that I am familiar with.

1. Take the tank to a radiator shop - they can get them cleaned up.
2. Use BB's and diesel fuel. -> http://www.ehow.com/how_4421040_clean-out-motorcycle-gas-tank.html

There is another method I have used for rust in a tank but I don't think it will help with varnish.

http://www.ehow.com/how_7660779_remove-motorcycle-fuel-tanks-electrolysis.html

Good luck

[John U.]

Acetone and drywall screws. the screws are to scratch up the surface and to remove rust preparatory to coating the tank. If you don't have a rust problem you don't need the screws. Check Caswell Plating on the web, they have epoxy coating products but also tank cleaning instructions.

[Magellon]

Took my tank to a Rad shop, He cleaned inside and coated it with some type of RED protectant stuff. Got it back and took a ride, after about 1 mile had a loss of power and died. Restarted and same thing. Found that he had PLUGGED the vent tube.  Had to use a few drops of Methyl Ethyl Ketone to clear the tube. Wasn't a happy camper but problem was solved.

[alph]

I have an old Yamaha fj600; I used Methyl Ethyl Ketone and a bunch of BB’s for a BB gun.  Hung it from a bungee cord and bounced it all over the place!!  That worked great!!  It did take about an hour, if you could rig up a way of turning your tank and let the BB’s tumble around in it, that would be much better!!  The hardest part is getting all the BB’s out!!

Good luck!

I would have to be very VERY carful of using Acetone in a gas tank, mainly because of the paint!! 

[BonS]

Chain and acetone works very well and you can be sure that you've gotten it all back out.

[Pete]

The Solution/battery charger method does an excellent job of removing rust. But sometimes it may cause some bubbles to appear in the exterior paint. I think this has something to do with the original surface prep when the tank was painted.

In examining these bubbles it appears to center around a tiny spec of rust that was covered with paint.

MEK will clean just about anything including some paints, so be careful. MEK is also not a health cocktail either so watch yourself. Do it outside with a fan blowing away from you.

[Buda]

http://kzrider.com/index.php?option=com_content&task=view&id=22&Itemid=11 I found this helpfull for my kaw...should work the same for the valk.
Tom

[Ricky-D]

I've never never fully understood the rust problem. None of the gas tanks I have had have ever gotten any rust in them, at least not any to speak of!

But the comments I have read on other motorcycle forums regarding coating the inside of gas tanks have been negative in general content and unhappiness over long term results of doing the coating.

Most report on the failure of the coating to remain adhered to the metal surface and the resultant clogging of the outlet and filter screen assembly of the petcock.

My suggestion would be to use no interior coating in your tank. 

So, if rust in the tank is bothering you, it would be good to get it out. But, that is all I'd do. Nix the coating.

***

[pvan]

Rusty tanks are a drag... but I have dealt with many since I collect early 70's Kawasaki muscle bikes. Since some of these old tanks are hard to find and very expensive I have tried many options.

The most effective is a quart of muratic acid with a handful of bb's, tape tank shut, then vigorous shake followed by letting the tank sit a different angles, shaking more times, then look inside and if clean, flush with water, if not seal and shake more, then water flush, let tank dry.

Next is use a small bottle of naval jelly shaking it all around, rinse with H20, then leave the tank sit in the sun for a few hours, turn it over and let it sit in the sun for few more hours. If no sun I use a heat register in the house.

This system works great for cleaning, but if the surface is clean but "rough" then I CREAME it. Creame is basically a two part epoxy. The key to a successful long lasting sealer is the tank must be clean and the Naval Jelly allows the creame epoxy to adhere very well due to its iron etching properties.
The problems with sealing tanks are related to not getting them clean enough followed by not doing the iron phosphate etching before using the expoxy sealer!

[Smiley]

I recently had a rust problem with my 1948 International H tractor's gas tank and used a product called "Por15" and am very happy with the results.
1 - Drained and flushed tank with water several times to get big chunks of rust out and dried with wife's old hair blower duck taped to gas inlet for drying out water
2 - Used their "Marine-Clean" twice to remove varnish and more rust
3 - Next used "Prep & Ready" to etch tank for next product to stick, primer prep type thing
4 - Dumped can of "Por-15" into tank and rolled it around to coat inside
Their web-site has available kits and more detailed information.
http://www.por15.com/
Worked for me, hope it'll help you!

[Romeo]

First of all I would like to thank everyone for their input. I neglected to say in my original posting that my problem isn't rust, its varnish. I am restoring a 1975 cb550 that has sat since 1985. It has quite a buildup of varnish on the bottom of the tank. I was thinking about putting Gunk carb cleaner in the tank along with some sort of agitator, wheter its beebees or screws. The cleaner I am referring to comes in a gallon can, with a small pail in it to soak the parts in. It is very caustic, but works wonders on carbs.

[gordonv]

I would think any good carb/injector cleaner that people have talked about so much around here for cleaning out a poor running bike, would work. Pour it out full strenght in the the tank, splash it around inside the tank every time you think about it, letting it disolve the varnish inside.

Pour it out, inspect, not done? repeat till the tank comes out clean. Either get gas in in quickly before it does rust, I was going to use an engine oil fogger (storage) to oil the inside of the tank to store without fuel in it.