Cleaning Out Rusty Petrol Tank

[MikeP]

Sorry to all if the answer is tucked away in an old post - I have looked.

I'll swilled out my GPz tank for about 2hrs with petrol to get rid of the bigger rust flakes and now I'm at the stage of trying to find a better method and one that might finally allow clear petrol to flow.

Any ideas chaps?

[chrisu]

harpic and coke

[MikeP]

Thanks Chris, if it doesn't work I'll drink it myself

[chrisu]

apparently.....................

"I used 3 parts coke (cheap coke, not pepsi) to 0ne part harpic.....bloody good stuff, works a treat. Be careful not to let it fizz up and over onto the paint work. I poured the liquid in very slowly to minimise fizzing up. Just leave for 5-7 days and hey presto, no rust left. Oh, yes must remove fuel tap and block off the hole."

[keith mayall]

put some stones in it or nuts and bolts to swill round to get the loose bits off.

[Surfdeneige]

swarfega metal cleaner

[ADRIAN H]

apparently.....................

"I used 3 parts coke (cheap coke, not pepsi) to 0ne part harpic.....bloody good stuff, works a treat. Be careful not to let it fizz up and over onto the paint work. I poured the liquid in very slowly to minimise fizzing up. Just leave for 5-7 days and hey presto, no rust left. Oh, yes must remove fuel tap and block off the hole."

+1 done this a few times worked a treat

[MikeP]

Thanks guys, I'll give the Harpic + Coke method a go as it's cheap and not too evasive - compared to the nuts and bolts. I've seen what a 1p looks like after being submerged in a saucer of coke. It sparkles.

https://www.youtube.com/watch?v=7xd2MZKPzMA

[Sam Johnson]

How much do you put into the tank, do you fill it right to the top or will say 3 litres of cheap supermarket coke and 1 litre of Harpic do the job?

Thanks
Sam

[chrisu]

How much do you put into the tank, do you fill it right to the top or will say 3 litres of cheap supermarket coke and 1 litre of Harpic do the job?

Thanks
Sam

^^^ this - seal top and bottom and slosh around regularly

[MikeP]

Finally took the tank outside and poured the 12 litres of coke + Harpic additives into a bowl (to be disposed of in a responsible way ) and it smelt disgusting. I can't say that the inside looks noticeably cleaner so I've bought another load of supermarket coke and Harpic ready to give it a final "flush". This time I'll fill with a larger volume.

How did your tank clean go Sam?

[nigel bessant]

harpic and coke

Yep, +1. Guaranteed to work.

[Sam Johnson]

Not done it yet, picking the bike up this week.
Its an old Suzuki T500 that will need cleaning as
there is a lot of rust inside it.

Sam

[redzee]

Deox C, used it on two tanks with great success. Failing this I've also used reverse electrolysis, it does a good job on heavier rust but keep an eye on it if the metal is a little thin.......
Google both methods.

[MikeP]

Update: The Gpz tank had been stood for 18 years without fuel and the insides was rusty with big flakes of rust when I swilled it out with water. From above, I tried the Harpic and coke concoction but that wasn't as successful as anticipated.
My latest attempt is using white vinegar. To fill the tank I needed 21 litres and bought 25 litres from Amazon at approx £18. Having read-up I didn't have to remove the fuel sender or the tap and filled it up very near to full. I left it for 5 days and emptied by removing the fuel tap and flushed out with water to neutralise the acid and wash any flakes out.
The end result was a dull grey metal finish in the tank. The vinegar/acid was really brown with rust - I'll filter it later for re-use if need be. I did protect any paintwork with tape and clothes and didn't see any paint dulling from any lose splashes.
Give it a go.