vinegar to clean the gas tank

[robin1731]

Not a good idea.

Rebuilt a set of 75 GL carbs last fall. Guy brought the bike over and I installed the carbs and ran it on the test tank. Did not use his tank as it needed cleaned. He said he would do it in frame.

Contacts me a month or so later. Bike won't start. Tried starter fluid. Backfire through the carb plenum. I can't get to it till spring.

He brings it over and yes, it won't start. Look at the fuel filter and it has red "crap" in it. Open the drain screw on a couple of carbs and same red crap comes out. Pull the carbs and pull the bowls. Very ugly. Pics to follow.

He obviously did not get the tank rinsed out of all the vinegar. And that red goo sat in the carbs all winter. Pretty much corroded/ate away at everything. Time to rebuild another set of carbs. And replace the tank and fuel pump (which was new).

Fast forward to this weekend. Carbs are done, tank changed. Fuel pump not swapped yet and I again wanted to run it on my tank first.

Still no start. Check compression. 3 of them are low but have enough it should run. One has zero. Do a leakdown on that cylinder. Leaking past the intake valve. Pretty sure the valve has rust/corrosion on the face/seat. If you look down any spark plug hole you see this rust/corrosion/red crap on the valves and on top of the piston.

Having him come over later this week to discuss options.

[5speed]

I used apple cider vinegar in the tank on my 76 and it did absolutely nothing to remove the rust. I ended up doing the electrolysis method on it.

[robin1731]

That last pic of the bowls was after I vapor blasted them.

[Whiskerfish]

Self induced pain.

[NotSoLilCrippseys]

Holy cannoli, Batman.

Glad I didn't try vinegar in our tank, which is actually a recommended approach all over the Internet. Goo like that would probably have me throwing in the towel - after I soaked it in tears. (I do want to imagine I'd have been sure to flush things really well, but then...)

[robin1731]

Holy cannoli, Batman.

Glad I didn't try vinegar in our tank, which is actually a recommended approach all over the Internet. Goo like that would probably have me throwing in the towel - after I soaked it in tears. (I do want to imagine I'd have been sure to flush things really well, but then...)

Yeah, he thought he flushed it well too.

[Rat]

Well ... vinegar is an acid, low power, but acidic ... flushing won’t get rid of it, needs to be neutralized ...

High school chemistry ...

Gord

[05c50]

Well ... vinegar is an acid, low power, but acidic ... flushing won’t get rid of it, needs to be neutralized ...

High school chemistry ...

Gord

I've found that no matter how much water and how quickly you flush the tank, the vinegar continues to eat away at the metal. I use baking soda and hot distilled water to do several flushes immediately after draining the vinegar, followed by a coating of 2 cycle oil.

.........Paul

[desertrefugee]

Thanks for sharing this, Robin. That is a real eye-opener. (Feel bad for the guy. He was trying to make it right).

[robin1731]

The cylinder head from the one with zero compression was ugly. See the pic. I did get/make the time to dig in to this and get it going. Ended up using a different set of heads. Pistons cleaned up nice. The bores were not as bad as I thought they might be. Runs good now. Owner is picking it up tomorrow or Thursday depending on the weather. He is about 2 1/2 hours away.

Lesson learned for him.

[ericheath]

I used citric acid crystals on a tank several years ago. It worked great, but I took seven days to do it. I am under the impression that it is chemically similar to vinegar, but I’m not a chemist. I neutralized it with baking soda and then rinsed, dried and coated with oil/transmission fluid. I did give the gasoline a heavy dose of Stabil Marine.

I think I better take a look since it has sat seven years since. If it’s bad, I’ll add it to this post.

[pidjones]

Whatever you use to clean rust from a tank, you need to use acetone (or similar solvent) to remove the varnish first. Then dry that out and use vinegar, electrolysis, Evaporust, Metal Rescue, whatever. Any acid will need good neutralization. Even molasses (Yes, kit is used also) is mildly acidic.

[ericheath]

Mine, which was cleaned in situ with citric acid crystals and distilled water, looked pretty good after at least seven years. There were a few small spots of surface rust here and there. It has been sitting with 1/4 tank this summer. I should fill it up.

[Lucien Harpress]

Meanwhile, I'm over here giving side-eye to a tank that still needs cleaned but haven't gotten to yet, and reconsidering my options how....

[robin1731]

Meanwhile, I'm over here giving side-eye to a tank that still needs cleaned but haven't gotten to yet, and reconsidering my options how....

Evaporust. Buy a 5 gallon can. Not cheap but it is reusable. And it isn't acid so no worries about that. You can dump it on the ground and not worry about that. Works very well. I just pour it through a paint strainer when I'm done and put it back in the container.