Fuel filter

Haggis

Hero member
I can't resist the oldie-but-goodie...

The mechanic inspects the badly running engine and says, ?it?s not a big deal. Just shit in the carburetor.?

The customer responds, ?Oh, OK! How often do I have to do that??
 

Dellortoman

Hero member
Here's my take on rust:

It's best to prevent rust happening in the first place, but sometimes there's no way to do that. So if you have rust, there are two things you can do with it - get rid of it or convert it into something else.

Getting rid of rust can be done mechanically or chemically.

The mechanical method is as simple as it sounds. Knock it off with a grinder or sanding appliance. In the case of a fuel tank, you can't get at it with power tools so agitating it with abrasive material inside (such as pointy screws, nuts, etc) is about as good as you'll get.

To remove rust chemically, you just need a weak acid. Citric acid is good because it's non toxic and you can wash it down the drain when you're done with it. Phosphoric acid is just as good, or maybe better, at removing rust but I think it's more problematic to dispose of in a responsible way. Either acid will completely dissolve the rust. You can then hose it off leaving a clean metal surface. Generally washing it off is sufficient, but some people suggest using a neutralising agent like a weak caustic solution. I don't think that's necessary because then you have a caustic substance to get rid of. Perhaps a solution of baking soda would be harmless enough as a neutralising agent.

For the removal process to be effective, you need to completely fill the tank with the acid solution and let it soak for a couple of days.

Once you've removed the rust, you're back to a clean steel surface that may rust again in time. A little surface rust is no problem.

Converting rust is a chemical process. You can buy rust converter at hardware or paint shops. The basic ingredient in rust converter is tannic acid. It reacts with the rust and converts it from ferric oxide to ferric tannate, a hard bluish-black substance that's chemically stable. There may be other chemicals in rust converter to aid the process, but tannic acid is the main active ingredient.

With rust converter, you don't need to fill the tank. Just put enough in so that you can slosh it around to coat the entire inside surface. The chemical conversion process only takes about 20-30 minutes. It doesn't matter if you use too much. Just drain off the excess afterwards. It may need a couple of treatments if the rust is thick.

The blackish converted rust forms a barrier that offers some protection to the steel surface, inhibiting further rust.

The 'rust inhibitor' that comes in the fuel tank liner kit is probably rust remover, rust converter, or a mixture of both.

Preventing rust is some kind of treatment to stop rust forming in the first place. It's usually some kind of protective coating and can include paint systems, a tank liner, a coating of grease, spray-on stuff like fish oil or lanoline, electroplating, galvanising, etc. There's a whole bunch of techniques. Rust can also be inhibited by electrical means, such as a sacrificial anode. Sometimes products in hardware shops are mis-labelled as rust inhibitor when they're actually rust remover or converter. If you see a bottle in your hardware store labelled "Rust Inhibitor" either read the instructions to try to figure out what it does, or put it back on the shelf and choose a more clearly labelled product.

Back to fuel tanks ...

If you just want to eliminate fuel contamination from bits of rust, I'd suggest you start with a mechanical rust removal process to get rid of any loose flakes, then hit it with rust converter to change any remaining surface rust into ferric tannate. That'll give you a lining of sorts inside the tank. The black ferric tannate is fuel resistant and will protect the underlying steel from further rust.

 

Cuda

New member
Location
New Zealand
Thanks for the detailed description dellman. And everyone that has contributed and offered advice. Much appreciated.
The floats are Not pivoting freely on The float pins. I flushed out the float bowls and the float valves seal as they should. So i?m suspecting that the lack of free movement with the float on the float pin might be the issue. Anyone experience this issue. Any idea on how I could rectify the problem. I should say I did buy a new float and have the same binding issue as the old one.
Cheers Dave.
 

Ventodue

Hero member
Cuda said:
<snip> The floats are not pivoting freely on the float pins. <snip>

Hi Dave,

Ah!  Different diagnosis, different solution ...  ;)

First off, run a bit of fine emery over the pin (not at the very end, nat', cos that should be a reasonably tight fit in the housing).  The pins should be shiny bright, but over the years a bit of crud can build up.  (Making sure the pins are clean and smooth is just one of those second-nature things that anyone who does carb re-builds does without thinking ...)

If that doesn't work, then try gently opening up a little bit the rolled over bit that forms the hinge.  But be a little cautious because this shouldn't really be necessary.

The floats should move up and down very freely, of course  :).  Sometimes they get caught up on the side of the float bowl when you mount that.  A gentle rap with the handle of a screwdriver on the side of the float bowl before you finally tighten the retainer nut stops it happening.

(Btw, the fella who rebuilt your carbs should know all this, especially about making sure the floats were ... floating.)


 

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mauricejota7604

Hero member
The problem with the floats in Daves bike is they are the new white all plastic variety with no brass frame (they are not very good quality compared to the earlier ones and are slightly lighter at 8 grams.
 

Cuda

New member
Location
New Zealand
Ok, I will give the pins some attention and hopefully that will solve the problem. As previous owner Maurice stated the floats are the replacement 8.5 gram white ones. Thanks for help, I?ll let you know how things go.
Cheers Dave.
 

Ventodue

Hero member
maurice turner said:
The problem with the floats in Daves bike is they are the new white all plastic variety with no brass frame (they are not very good quality compared to the earlier ones and are slightly lighter at 8 grams.

Ah.  Thanks for that bit of info, Maurizio  (bigthumb).  Like this?  I can't pretend they look quality ... :eek:

 

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CLEMTOG

Hero member
with the white ones, in many cases the bore for the pin is too wide, and that is where a potential hang up exists as well, easy to shorten, just use a sandpaper block and then de-burr, be sure to blow all debris away with CA, and  also wash with brake cleaner.
CLEM
 

Cuda

New member
Location
New Zealand
Yep that looks like a picture of em upside down. One of the floats on my bike had a hole on the right half Where the seam is plastic welded. Didn?t seamed to be lined up properly during production. It looked like it had been heated and pressed together missing a small spot. Not the best quality control. Thanks Clem. I?ll check that as well.
 

laverdas

Hero member
Going to put my head on the block and tell you what I do and that is to take the taps off and filler cap.
  Get high pressure washer car type is good any thing around 110 - 130 bar and blast the fuck out of it.
Then dry and pour some diesel in shake and pour out. May smoke a little at first but saves all the bollocks.
Regards Andy 😁
 

Cuda

New member
Location
New Zealand
I’ve filed down the ends of plastic tubes that pivot on the float pins. The floats would intermittently stick when activated by touch on the posts that Secure the pins. Thanks clem. Initial results indicate this may have solved the problem. Thanks everyone for the advice, much appreciated. very helpful.
 

Bigfeesh

Full member
Location
Geordieland UK
I did the citric acid treatment, great result, used a fish tank heater to keep the solution warm but 3 days and it all dissapeared nicely, then tip the rusty solution down the drain!
 

Paul Marx

Hero member
Location
France
I used electrolysis on my 3C tank. Bicarbonate of soda in water filled tank. Iron electrode in the tank and 12 V battery charger.
Then a rince with phosphoric acid solution.
Rust didn't reappear after 6 months empty on the floor of the garage.

Paul
 
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