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Lat Fuller

2025-06-04, 05:57:00
Does anyone have the specifications for the oil inlet valve spring for early 2 3/4 engines - Part number 424.   I have tried to order one from the club spares but apparently Jeff Swan is indisposed at the moment.

skapoor

2025-05-19, 09:23:12
I am looking for a carburettor for veteran Douglas motorcycle engine-13651. Could you please help me with this?

Dave

2025-01-07, 19:16:39
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Dave

2024-06-11, 21:02:05
Have you tried the new Drafts feature yet? I just lost a long message today and learned my lesson. It is a good idea to save a draft of any long post you are writing. You can then just keep writing and keep saving a draft, knowing you have a backup if there is a glitch. The draft is automatically deleted when you post the message.

petrol tank flush

Started by Sgtbiro, 25 May 2021 at 19:26

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Sgtbiro

Hi all i need to flush my Dragonfly's petrol tank and was wondering what was the best thing to flush it with, i dont know weather to use petrol or could i just use some really hot water.
and make sure it dry before putting any petrol in it.

Cheers Kevin..

cardan

Hi Kevin,

Depends on whether you are trying to remove rust, gunk, or something else!

I use really hot water with detergent, plus a handful of nuts. Shake like crazy for a long time. Repeat if necessary. Wash with clean hot water, rinse with methylated spirits to dissolve any remaining water. Allow to dry, then rinse with oily petrol (or squirt with WD40) to stop new rust.

If it's gunk, you might need to use acetone or similar, without nuts, but be aware of fire/explosion risk.

Leon

EW-Ron

Quote from: cardan on 26 May 2021 at 01:19
but be aware of fire/explosion risk.

A not inconsiderable matter.
Also, best done outdoors, so the fumes can't get you either ...

Sgtbiro

Thanks guys I was leaning that way but it's nice to get people's opinion thanks again.
Cheers Kevin.

yosemite

Remember if you use acetone it will rapidly remove any paint it comes into contact with.

Dads bike

Evening Kevin
If it is just surface rust, internal of the tank, no oil or varnish contamination. Then I use warm water mixed with Molasses mixed at 4:1.
Use cheap animal feed Molasses from your local animal feed store it's about £8 a gallon.
Mix it up with warm water, fill the tank and leave for about 48hrs, drain the tank into a container for future use on other rusty parts and flush the tank with clean water, it should come out back to bare clean metal but will rust again very quickly unless treated with an oily solution.
The chemical reaction of the molasses with (iron oxide), rust, makes the rust missable with water I.e the rust dissolves into the water. The longer you leave it the cleaner and it's not toxic.
Note it only works with iron and steel, won't work on Alloy, brass etc.
Not witch craft, honest.

Steve

patrickwhitty

I haven't tried the molasses method though I believe it works well. I have a vast plastic water tank full of washing soda solution which I use for de-rusting quite large pieces of car. It is slow but very effective and it is the best paint stripper I have ever used. The paint simply slides off like a wet transfer. I have never used it for the inside of a tank but it would work well enough, there are several links on the internet to using the method including some on de-rusting the inside of fuel tanks http://bikerdiy.com/projects/general-project-related/rust-removal-the-electrolytic-method/  You need a battery charger, the negative lead is attached to the piece you are working on (the tank) and the positive lead is attached to a piece of scrap steel. The tank is filled with washing soda solution and the scrap steel suspended so that the lead is above the solution and it bit of steel doesn't touch the tank. Switch on the power and leave it. Bubbles of hydrogen will form on the inside of the tank so it is better to do it in a well ventilated area. Like the molasses method, it will only work on iron or steel. The rust is chemically converted back to steel, the scrap steel gets very rusty and eventually falls to bits. You can't 'over cook' it. When I first set up my tank I bought a fancy battery charger which could run at a very low rate but it was so clever it told me my battery was faulty and refused to work. If it was that clever it should have known it wasn't a battery. The washing soda never goes off and it is non-toxic. Eventually it evaporates, you just add more water.
Patrick

EW-Ron

Quote from: patrickwhitty on 28 May 2021 at 07:43
The rust is chemically converted back to steel,

That part is not quite correct. ?
The hydrogen forming on the steel surface breaks the rust particles free, and they fall off.
Or something like that. Molasses does something similar. As does citric acid etc etc.
The sludge in the bottom of the tank tells the story ...

You need a blast furnace to make clean fresh steel from rust, not necessarily in one operation either.  BIG energy.
Nit picking ? 
Cheers.