Whats in my gas tank??

[mjn12]

Alright, so I need to clean out my gas tank. 

It seems to have  a little rust in the bottom and some other substance I can't quite identify.  Its a brown liquid, sits below the gas and behaves like oil does in water (stays together in "globs", sticks together.  Could it be water that got in the tank somehow or this just varnish that hasn't come out.

As for cleaning the tank, i really dont want to go through with the muriatic acid and sealing since the tank is banged up and will be replaced once I fnd a decent one for sale.  I've already got an inline fuel filter but I don't like the mystery liquid and rust going into my newly cleaned carbs.

Could I use something like CLR to remove the little rust deposits - maybe with some of those aquarium pebbles for some abrasion? I just can't justify spending 35 on something I'm going to be replace in a few months.

[scottpA_GS]

The "stuff" could be a past attempt at Cream or another tank fix... I tried cream and It made a mess of my tank. I think for a temp fix you could just rinse it out with some Kero, change the filter and roll 

[makenzie71]

ummm brown foggy stuff is usually rust/water.

[mjn12]

I'm going with the gas and water theory.

Since I'm a nerd (aka engineer) I got online and looked up the specific gravities of gas and water to make sure it would behave like that. Kind of ashamed about that.

[Egaeus]

IF you were a true nerd, you'd already know that gas is lighter than water.   

[The Buddha]

Yes, but how much ... BTW you'd also know that oil is lighter than water and by quite a bit really.
Cool.
Srinath.

[Kaizer]

I have a better idea on how to fix your gas tank. Take it to your local radiator place, and have them acid wash it and line it with red top lining, and it will last the lifetime of your motorcycle. They did it for me for $32. It is a lot cheaper and neater than doing the 3 step system yourself, and it will prevent from rust forming in your tank again. Hope this helps!

[Egaeus]

Yes, but how much ... BTW you'd also know that oil is lighter than water and by quite a bit really.
Cool.
Srinath.

Gas is about 6.2 lb/gallon, water is 8 lb/gallon, and no, I didn't look it up.  I've known water, and I encountered gas a few days ago when working on the ethanol conversion problem.

[MarkusN]

Yes, but how much ... BTW you'd also know that oil is lighter than water and by quite a bit really.
Cool.
Srinath.

Gas is about 6.2 lb/gallon, water is 8 lb/gallon, and no, I didn't look it up.  I've known water, and I encountered gas a few days ago when working on the ethanol conversion problem.

Gee, I fall in love with the SI all over again. Density of Water is 1 [kg/l]. Most technical formulas work without any other coefficients than 0.5 from an integration here or there. The list goes on. And no need to worry about Mars probes that might not reappear after swinging into orbit.

[ducati_nolan]

Back on topic here, I'm sure it's just rusty water. If it were oil, it would just mix with the gas and make it a little darker. For the time being, I'd just drain the gunk out. You should probally remove the petcock to ensure that it's not clogged and clean it. I like your idea of using aquarium rocks to knock the stuff loose.

I've never used CLR but I think it's water based, so if you use it you'd want to rinse it out with gas after it's dried. Probally just sloshing some gas arround in there and then keeping an eye on your fuel filter and cleaning/replacing it when it fills with gunk would be fine for the time being. As long as you take care of the water and the big chunks of rust, the filters should be able to take care of the rest of the rust untill you get a new tank.
Good luck 

[mjn12]

I emptied the gas in the tank and sloshed some extra around in there, I got probably close to 10oz of that water/rust mixure out. 

I'm talking to a gas tank restoration company in the area to see what it will cost them to acid wash/ coat it. 

Bike has to be inspected in the next 5 days or I have to pay for another temp plate.  If I don't get the bike inspected i won't get the title. Inspection costs $75, ugh.   

Oh and nolan - I will ship those jets soon.  I forgot to take the jets with me this weekend to ship while I was out of town, They should ship tomorrow if I can get out of work before the Post office closes.