Tank rust

[P.]

Hola

So my new to me bike is a little rusty in the tank

https://imgur.com/a/XP9DVxv

What's the best/safest/most effective way to clean this. It doesn't look too bad, but I want to sort before it gets much worse. It's a CBF600, carb variant.

Thanks all

[Nobby the Bastard]

Rustpal.
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint ST 1050

[Islander]

POR-15?

If you just treat the rust it's going to come back. It's probably better to line it.

[trevor saxe-coburg-gotha]

[Bhud]

That looks terrible. From my experience with bike projects, I would never run even a slightly rusty tank. It's less hassle to fix the tank than remove and clean carburettors. I've had luck with Tank Cure. Follow directions on packet and shake it up like crazy, lots of times, for a whole day, with a bag of nuts. Don't waste time on vinegar and all that rubbish.

[A100man]

Vinegar takes forever because it;s weak, I;ve also tried electrolysis with not much success.

For me it's phosphoric acid every time. about 15% Conc is all you need.

A bloody good shake with a few handfuls of wood-screws will get into the corners
and get rid on most of the loose stuf. Then brim the thank with acid. (almost). leave some air for sloshing - you will also have to make blanking seals for the tap and sender. I'd leave for 24 hr sloshing when you can remember.

Rinse with water then swill out the tanks with meths/ethanol to collect any remaining water.Never bothered with a liner just fill with fuel.er.

This method may of course reveal pin holes in which case leading or if you must a liner
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Now: A100, GT250A, XJ598, FZ750

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600

[jaffa90]

What lies at the bottom of the tank both sides?
I would remove the tank internals and tape off and throw wood screws (as mentioned), nuts, bolts, chippings and anything sharp.
Then tie the tank on a Harley pillion seat and ride on uk roads to loosen all the crap and remove it. Buy an ethanol friendly tank sealer and follow the instructions but remember to protect the screw threads for refitting.
Also if possible fit an inline fuel filter.

[trevor saxe-coburg-gotha]

totally agree w/ fuel filter - essential if tank is to be used (i.e. used w/out liner)
____________________
"Life is a sexually transmitted disease and the mortality rate is one hundred percent."

Mobylette Type 50 ---> Raleigh Grifter ---> Neval Minsk 125

[Robby]

My usual thing is phosphoric acid, and I've done a lot of rusty tanks with it. Full instructions:

First thing to note. Phosphoric acid will kill rust and leave the steel looking galvanised, but it also eats through aluminium and will get past some rubbers (but more slowly). So any aluminium parts like fuel tap and fuel sender must be removed and the holes plugged off. I tend to make up a little metal plate to bolt over the hole(s) with a bit of hylomar blue. Some of the acid will drip past this, but not much, and it doesn't harm paint that much.

Do as much of this as possible outside, or in the garage.

1. Clean out the tank. I don't mess around with handfuls of bolts generally, because it can be a pain in the arse getting them out. I drain the fuel, fill and empty with water a couple of times, then fill with a mixture of caustic soda and water and leave it for an hour or so. This shifts any dirt, sludge, basically anything organic and emulsifies anything oily.
Drain and rinse a couple of times with water. If the fuel tap hole is plugged off, a squeezy siphon pump works well for getting liquid out.

2. Acid time. I buy a 4 litre bottle of 40% phosphoric acid off ebay, pour it in the tank, and fill the rest of the tank with warm water from the tap up to just below the filler neck.
Do not overfill. The process makes bubbles. If you overfill, these bubbles will collect in a nice pocket and force acid out the filler hole, all over you tank.
Let it sit for at least 4 hours, longer if you feel comfortable with it. It will make fizzing noises. If you shine a strong light in the filler, you should be able to see how it's working.

3. Finishing off. Drain the acid, rinse a couple of times with water. Get as much water out as possible. I then pour in a bottle of meths and swill is around, then drain it off. That means that any water remaining is at least mostly meths, not mosly water.

If the tank is going back into use, refit and fill up with petrol as soon as possible. If It's going into storage, you want to get something on that metal to protect it from rusting. I tend use a mixture of engine oil and WD40.


No matter how much water you think you got out, you will get some in your carbs next time you switch on to reserve. Carry a screwdriver to drain the float bowls for when this happens.

I don't use any kind of tank liners. They might work, but I've had them fail in the past so I avoid them.

Both the caustic soda and the phosphoric acid can be poured down the sink or loo to dispose of them. Phosphoric acid will make your loo very clean, it dissolves limescale.

[P.]

I didn't think the rust was that bad to be honest, I've had a lot worse but I'd like to ride this bike some distance so happy to sort.

I have plenty of space in garage and outside so I'm guessing if I follow your steps Robby (I have a load of meths already but will grab some acid) then that should remove the messy rust and just drain out nicely.

I have no tap/obvious reserve, it has a fuel light and presumably just warns you, I'll obviously rip all of that out before doing it so it's bare tank only.

I couldn't find any decent blue tanks online to be honest, there are no dents on the current one and it's in decent nick otherwise.

I can replace the fuel filter/tap assembly should it need that. I've got plenty of time.

-edit-

Just went poked it a little with a screwdriver just to scrape and see how bad it was, despite what it looks like, it's a remarkably thin coating of rust. I'll drain the fuel tomorrow after work and get to unbolting it all. If there was a new tank I'd buy it outright but all the ones I've seen under £100 are just doggy where as this one is actually clean.

[A100man]

So, phosphoric acid it is then..


____________________
Now: A100, GT250A, XJ598, FZ750

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600

[A100man]

oh yeah and no tank liners..
____________________
Now: A100, GT250A, XJ598, FZ750

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600

[P.]

Yeah cheers, I'll use the method Robby suggested as you also stated, see how it goes. Gotta work out how to get 10l out

[redeem ouzzer]

Flush it and run a big in-line filter if there is room.

Done.
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Be a REAL MAN!