How to stop a fuel tank rusting internally
Discussion
Hi, apologies if this has been answered before.
I’m ashamed to say both of my bikes (80’s and 90’s Japanese sports bikes in case it makes a difference) have been stored in my garage for a few years, on one of them the fuel tank rusts really badly internally, I’ve cleaned it once using Evapo-rust with good initial results but once cleaned the tank just starts rusting again almost immediately, I filled it with fuel but it just rusts above the level of petrol and over time the petrol evaporates and the whole tank is rusty again, I’ve just popped the filler cap and it is now completely covered in a thick fur like rust all over internally. Is there any way (once I’ve cleaned the tank again) to prevent it from rusting, please bear In mind that the bikes will continue to be stored and probably won’t get used much of at all in the immediate future due to other commitments at the moment.
I’m ashamed to say both of my bikes (80’s and 90’s Japanese sports bikes in case it makes a difference) have been stored in my garage for a few years, on one of them the fuel tank rusts really badly internally, I’ve cleaned it once using Evapo-rust with good initial results but once cleaned the tank just starts rusting again almost immediately, I filled it with fuel but it just rusts above the level of petrol and over time the petrol evaporates and the whole tank is rusty again, I’ve just popped the filler cap and it is now completely covered in a thick fur like rust all over internally. Is there any way (once I’ve cleaned the tank again) to prevent it from rusting, please bear In mind that the bikes will continue to be stored and probably won’t get used much of at all in the immediate future due to other commitments at the moment.
I have used this before:
https://www.demon-tweeks.com/uk/por15-fuel-tank-se...
Just need to to be very careful how you use it, as what is good at stripping the inside of the tank can also be good at damaging the outside.
The final coat is pretty much thick silver paint, so if there is anything like an internally threaded fuel tap this needs to be ideally plugged or if not tapped after it is applied.
https://www.demon-tweeks.com/uk/por15-fuel-tank-se...
Just need to to be very careful how you use it, as what is good at stripping the inside of the tank can also be good at damaging the outside.
The final coat is pretty much thick silver paint, so if there is anything like an internally threaded fuel tap this needs to be ideally plugged or if not tapped after it is applied.
Interested in reviews of the POR15 stuff as well.
My old transalp has a rusty tank that only made itself known when I applied some stripes to the tank and I think the use of the hot air gun to stretch the vinyl softened the paint which was obviously sealing it and allowed the tank to leak! It went from not leaking at all to pissing out within a day of the decals going on!! May be too far gone but also may be worth trying the POR15!
My old transalp has a rusty tank that only made itself known when I applied some stripes to the tank and I think the use of the hot air gun to stretch the vinyl softened the paint which was obviously sealing it and allowed the tank to leak! It went from not leaking at all to pissing out within a day of the decals going on!! May be too far gone but also may be worth trying the POR15!
I don’t like any of the tank sealants, it is hard to get them to reliably stick to the inside of the tank.
If your tank is structurally sound and not leaking…
Empty tank. Air to dry out. Manually/mechanically remove all rust possible. Degrease with hot water and washing up liquid 5 times. Allow to dry out. Degrease with alcohol 2 times. Allow to dry out.
Add a weak mixture of phosphoric acid and distilled water and leave it to react with the rust. Watch out for the fumes, do it in an open space. Drain. Rinse with distilled water. Dry quickly, I used a heat gun on low setting - a hairdryer would work too.
You will be left with no rust, and a dark grey phosphate layer on the metal, this layer is corrosion resistant.
Plenty of YouTube videos that show this process in good detail.
If your tank is structurally sound and not leaking…
Empty tank. Air to dry out. Manually/mechanically remove all rust possible. Degrease with hot water and washing up liquid 5 times. Allow to dry out. Degrease with alcohol 2 times. Allow to dry out.
Add a weak mixture of phosphoric acid and distilled water and leave it to react with the rust. Watch out for the fumes, do it in an open space. Drain. Rinse with distilled water. Dry quickly, I used a heat gun on low setting - a hairdryer would work too.
You will be left with no rust, and a dark grey phosphate layer on the metal, this layer is corrosion resistant.
Plenty of YouTube videos that show this process in good detail.
Any lump of tin will rust internally due to condensation forming, unless you can store the tank somewhere warm.
The old school method was to empty, clean and then swill some oil around the inside of the tank before storage - but that's a PITA if you suddenly get the urge to ride again.
The old school method was to empty, clean and then swill some oil around the inside of the tank before storage - but that's a PITA if you suddenly get the urge to ride again.
Bilt Hamber do a Fuel Tank Cleaning Kit and also a preserve.
Never had a bad experience with their stuff.
https://bilthamber.com/product/fuel-tank-cleaning-...
https://bilthamber.com/product/gas-mac/
Never had a bad experience with their stuff.
https://bilthamber.com/product/fuel-tank-cleaning-...
https://bilthamber.com/product/gas-mac/
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