Rust in tank

[maestro]

Hadn't gotten to ride at all this summer. Opened my gas cap and there was rust covering the inside of the tank. Drained all the fuel and filled the tank with a rust dissolver. After draining and running a couple more cycles of filling with rust dissolver I used a scope and looked around the inside of the tank and it looked clean. I then poured in some muriatic acid and rolled that around in the tank a few minutes to make sure all rust was gone. Rinsed it out with water. Then rinsed that out with ethanol free gas, twice. Filled to the rim with ethanol free gas. About three days later I opened the tank because I wanted to replace the cap seal. There is surface rust in the middle of the tank, right where you can see looing in the opening, and it is all completely submerged with gas. What am I missing?

 

[drgnrdr750]

Normal oxidation. This will keep happening because of the metal. Only thing to do to prevent this is some type of tank coating. If you decide not to coat the tank make sure you have filters on the lines to prevent carburetor problems from the rust.

 

[hinksy]

I used evaporust on mine and the same happened . I was told about vinegar , so I used that and finished with baking soda to nuetralise it and it did not come back

 

[madmtnmotors]

Muriatic acid is pretty intense. If using something that strong following it with a baking soda rinse to neutralize the acid would probably be a good idea. Thoroughly rinse the acid out before the baking soda rinse. Baking soda mixed directly with muriatic acid could react with some vigor.

 

[maestro]

Thanks for the tips. How much vinager did you use and what ratio water to baking soda for the final rinse?

 

[hinksy]

I soaked it for four days and i used 20 litres of plain white vinegar , it is only $1.00 per litre here . And I used about half of a 500gm pack of baking soda . Flushed out the vinegar with water first then put in the soda with four or five liters of water and shook it around the tank for a while . Then flushed out with clean water , dried and put a two stroke mix in till I filled it with fuel . That was almost a year ago and it still is clean

 

[maestro]

Thank you. I'm going to try that.

 

[UK K6]

I used Evaporust and washed it out with petrol. Probably less than a couple of gallons and 2 or 3 rinses, to get it clear. My tank wasn't bad to start with though, no deep pitting etc., just discoloured.

Maybe cleaning out with water causes flash rusting?

I've done 5,000 miles since and the carbs stayed clean, so I think the process got everything out.

 

[PaPa Garry]

Hadn't gotten to ride at all this summer. Opened my gas cap and there was rust covering the inside of the tank. Drained all the fuel and filled the tank with a rust dissolver. After draining and running a couple more cycles of filling with rust dissolver I used a scope and looked around the inside of the tank and it looked clean. I then poured in some muriatic acid and rolled that around in the tank a few minutes to make sure all rust was gone. Rinsed it out with water. Then rinsed that out with ethanol free gas, twice. Filled to the rim with ethanol free gas. About three days later I opened the tank because I wanted to replace the cap seal. There is surface rust in the middle of the tank, right where you can see looing in the opening, and it is all completely submerged with gas. What am I missing?

Fuel tank sealer of course. People use different products. I prefer Red Coat sealer myself.

 

[WhiteWidow]

When putting your bike up for storage,
I found that draining the tank then spraying the inside with WD-40 prevents any formation of rust. WD indicates WaterDisplayment. Modern Fuels are POSION to a Metal Tank if left to sit for an extended period of time.

 

[Loki]

Evaporust on order for the derust, I'll also be doing an acetone wash as I can't tell if there has been a sealer applied previously then once it's clean and dry I will be applying a sealer, like the sound of Tankroxx which has good reviews and is made up in my home part of the country, also I use their ultrasonic fluid in my cleaner and have been very pleased with the results.

Loki