rust in tank

[TurboMike]

History:
Bike sat for a year or two but I'd start the motor once a month or so. I rode it 10 miles when I moved homes (and it ran ok surprisingly except for stalling at idle slightly). Then it sat for another year at the new house but I'd start it now and then. Idle stalling problem worse. Now it only runs on 2 cyl and I know the carb is beyond starting it every few weeks or carb cleaner to keep the old gas working.

I shipped the carbs to Arsenic to clean/rebuild. Fuel in tank was kinda orangy and when I dumped fuel (shaking tank updside down) it had some rust flakes in it. I did put in a fresh gallon or two when I moved it, but most of that gas was probably 3 years old.

So I was expecting the worst from the tank. Took off the petcock and everything so I could get some flashlight beams in there and surprisingly the tank was pretty clean. The top was fine and only some surface rust in a few spots on the bottom. Mostly by the petcock and gauge sender. So I'm thinking instead of a complete seal of tank, I can get away with putting something in there for a week or two until my carbs come back.

I've seen sand and water with a shake.... nuts and bolts with a shake.... vinegar.... acid.... chemical of choice (vaporust, kreem, metalrescue).

Not sure what to put in.

[shpielers]

For light surface rust, vinegar will work fine.

[TurboMike]

For posterity:

Filled tank with apple vinegar, shook it up and let it sit in sun for 3 days, rotated it a few times. Opened it up and all the rust was now loose in the tank, metal was shiny. Poured it out but couldnt get the loose rust out, so used a hose. The next morning I went to install on bike and full with gas, but in just 10 hours there was surface rust. Oops.

Put more apple vinegar in, shook it up.... next morning I dumped the vinegar, put in a little gas. Shook it up and poured out the petcock hole to get as much rust flakes out as possible. Did that 3 or 4 times with a little gas. Saw I got 95% of the rust flakes out and said fuck it and put the whole thing back together. Was hoping the few rust flakes in there would get caught by the filter.

Its been weeks of riding and no problems, other than the fuel sender not working anymore. I dunno if the vinrgar screwed it up or shaking the tank upside down so much to get the fluids out. So now I'm trolling the interwebs looking for a cheap fuel sender. But I'm still riding using the reserve switch petcock to tell me when I'm almost out.

[Kreylyn]

A suggestion when using a vinegar bath is to follow it up with a neutralizing bath for the acid. A 1/4 cup of baking soda in a 1 gallon water mix would be good.

THEN... follow up the rinse with a water removal rinse. Rubbing alcohol (1 cup) will pull all the water out, drain that.

Rubbing alcohol evaporates really fast, so run some air through the tank and it will dry very quickly before flash rusting.

Then use a 1 cup gas/ 1 cup oil mix to coat the tank. Drain the excess. That will give the metal a nice coating to prevent rust from forming on you again until it's back in use and filled with gas.

Run some water removal cleaner through the tank at least once every 6 months going forward, which will help prevent any water from pooling in the bottom to cause further rust issues. Also store the bike with a full tank as much as possible... no air or water = no rust.

Krey