RGS fuel tank rusty internal.

I

impamentor

Full member
Location
New Forest, Hampshire
Hi Guys

Been doing some work on the RGS of late (new clutch installed, all good) along with other bits and bobs ..cut to the chase, one of the tank taps started leaking, (those shite plastic things) so decided to whip it out and take a look, on doing so found quite a bit of rusty crud on the filter. On further closer inspection looking down the filler tube, oh dear lots of rust down there.

So the questions are, what is the preferred tap replacement and what is the best way of cleaning the rust from the internals of the tank..

Many thanks in advance and sorry if this has been covered before (I couldnt find it thru search)

Graham

 
Shake nuts and bolts in the tank until the cows come home then rinse out with a phosphoric acid solution.
Or electrolysis: fill tank with water and add a cup of bicarbonate. From a battery charger, connect a thick piece of steel dipping in the solution to + and - to tank. Takes 4 or 5 days. Clean plus electrode daily. Wash out with phosphoric acid solution. Works wonders.

As for petrol taps. replace with more shite plastic ones readily available.

Paul
 
I seem to remember RGS tanks have an issue where they rust in the corners that are hard to get deep into.
 
seal the tap threads with a piece of plugged rubber tube, fill tank to brim with water and a cup full of De-OXC, then leave in a warm place for about a fortnight, rinse out with plenty of water, dry the tank immediately with a hair drier, and actually get it hot, fit some aluminium taps available all over the place for Italian bikes and here in stock as well. If you are not using the tank immediately, pour in some two stroke oil and swill it around to cover all surfaces.

CLEM
 
The problem with RGS tanks is compounded by the fact that the edges are ladder welded, or for the technical ERW, thay are passed between two carbon rollers, under a little pressure and electrically welded, the difficulty is that those lower corners are much too tight a radius for the ERW machine to be able to get in there, the two inches or so that is unweldable by this method and is then completed with TIG, so you go from a squashed flange weld to an edge weld, not a problem there but at the start and finish point of the TIG you have large potential for leaks,
#and yes they rust as well, which I also feel is at least started by a  lack of proper post weld cleaning (either type)

CLEM
 
The problem with either of these methods is that the RGS tank has the long goose neck filler, not a normal hole at the top of the tank. That will make it extremely difficult to get the tank dry by evaporation and pretty challenging with electrolysis method to hang the piece of steel in there without touching the sides and get a good result. I did an SF tank with electrolysis followed by citric acid (deoxC?) and then phosphoric, rinsed and dried (then thoroughly sloshed around with a very strong petrol two stroke oil mix to prevent any surface rust) but accessibility is far better. Doesn't rinsing with methylated spirits work for getting moisture out? If so it could be the go here.
 
All the tanks I have repainted are acid-etched and coated with Tank Cure.
My tank has been like this since it was done in 2010 and the coating is still perfect.
 
Paul Marx said:
Shake nuts and bolts in the tank until the cows come home then rinse out with a phosphoric acid solution.
Or electrolysis: fill tank with water and add a cup of bicarbonate. From a battery charger, connect a thick piece of steel dipping in the solution to + and - to tank. Takes 4 or 5 days. Clean plus electrode daily. Wash out with phosphoric acid solution. Works wonders.
Click to expand...

I think that should be sodium carbonate (not bi-) and available as a 'pool' alkalai conditioner ... but does work with no ill effects on paint.
 
1200 JOTA said:
I think that should be sodium carbonate (not bi-) and available as a 'pool' alkalai conditioner ... but does work with no ill effects on paint.
Click to expand...
it's sodium per-carbonate that's the oxidiser and what precipitaes out is soda Ash once all the rust has been munched away. To be honest I power wash my tanks when the bike arrives and every year I take the tank off and empty them using a tunn dish and then put that fuel into the wife's car. And you will always  get some shit in the fuel which comes from the filling station.
  Splash a bit of 2 stroke mix as surgested.
Don't forget to leave in the sun until golden brown 🏖️
Regards Andy
 
Citric acid works as a de-rust agent. That's all Deox-C is, but citric acid is cheaper. available by the kilogram on ebay.

I hadn't thought of this before, but once you've de-scaled and de-rusted the inside of the tank, it should be possible to deposit a coat of zinc on the inside.

1200 JOTA's idea re the sodium carbonate gave me an epiphany. That's one of the ingredients of the electrolyte used for zinc plating. Fill the clean tank with electrolyte, bung a zinc anode in the filler hole and hook it up to a DC supply. Hey presto. Galvanised tank. No more rust problems.
 
Im de-rusting a tank from a 1950s MV Agusta 125.

Im using the same method as for my old Beemer tank which was rusty inside.

Oxalic acid..
Comes in powder form.
It is relatively innocuous  and  environmentally friendly. Put some angular pebbles or nuts and bolts in the tank.
Half fill tank  with hot water...add the powder with a spoon.
Then its shake it a while and keep working on it for as long as it takes. Repeating with a fresh charge doesnt hurt.

Then drain and rinse with water.
Use methylated spirits to absorb any remaining moisture and then drain.
I use Hammerite Kurist to pickle the metal. 150 ml.or so swished around in there for a while.
Then rinse..then meths again and the tank should be good.

I never leave my tanks empty over winter.




 
my annual pickled onion batch has to half of the jars added about eight of those nasty little bastard red chillies in them, currently gathering apples to make the annual supply of apple jelly, spicy apple jelly, and seriously spicy apple jelly.
CLEM
 
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