Fastback steel tank

The RGM tanks are ethanol proof. Not steel, but nearer to original perhaps?

https://www.rgmnorton.co.uk/buy/fastback-petrol-tank-early-round-badge-type_4930.htm

If you want cheap but prepared for work then buy off eBay, Royal Choppers and pummy8081 have good reports but they still come from India so buy bare steel. Once the prep work is costed you may then in total pay the same as RGM.

Have you thought of removing the ethanol from the fuel? Not practical if you need to fill up on the road but if a tankful will take you where you want to go it's an easy option.

I've been thinking about a couple of options to preserve the original look. One would be to "bag" the tank - basically stuff a plastic bag into the tank to hold the fuel. They do something like this with rally cars. Bags are made to order. Filler and taps are attached to the bag. Don't know how practical this would be.
The other idea is to make a basic aluminium tank and use the original GRP tank as a cover. The aluminium tank can be quite crude. Cut the bottom out of the original tank and drop it over, maybe put the base back too to complete the illusion. Will loose some volume but that seems entirely do-able.

Remove the ethanol by mixing the E5/E10 fuel with water. But of a faff but it does work.

Need a clear or translucent plastic 10 litre container with a tap (either seperate or in the filler). Sort of water container you'll see on any campsite. Put in 5 litres of gasoline, add a litre of water and shake vigourously. Allow to sit for a few hours with the tap at the bottom. You will see a water layer at the bottom and the gasoline on top. Almost all the ethanol is in the water. The trick now is the get the gasoline out and leave the water behind. So open the tap and run the water off until the gasoline layer is at the tap. Discard the water somewhere - it's contaminated so not a public sewer.

Trouble is that ethanol is an octane booster so you might need to add something depending on how much ethanol you've taken out. If you mark where the amount of water you add comes to on the container you will see how much ethanol has been drawn out. In the UK, premium unleaded is rated E5 but often contains little or no ethanol. E5 / E10 means it is allowed to contain up to 5 / 10% ethanol, but it doesn't have to. Shell V-Power seems to have very little so you don't waste much and most of that 98 RON is still left. Tesco Momentum is rated at 99 RON but does contain nearly 5% ethanol.

A Google search for "how to remove ethanol from petrol" will throw up lots more info.

Oh, and don't use that container for anything else.

You can add food dye to the water so you can see more clearly where the division between the petrol and the water/ethanol is.

Fascinating about ethanol removal but not practical for me on the longer runs

I have the same quandary ,though my fibreglass roadster tank seems very good on my recent US import rebuild project , I am wondering about having the tank lined and then painting versus bare indian tank and painting, 

do anyone know if the ethanol linings on the F/glass are effective in the l.ong term or how much this may be if done professionally ? 

Yes, the caswell lining is good but it needs to be applied correctly which is time consuming. If you ride regular then it will not be an issue. If you store the bike over winter months then do what the trial and racers do, drain the tank and leave the tank open. 

It can be applied yourself, what a company would do to line a tank I would not know. 

Just found this tread, I just posted a similar one. I am surprised that there are no comments or recommendations on a source for quality steel fastback tank 

If you value craftsmanship and have deep pockets: https://legendary-motorcycles.com/product/norton-fastback-alloy-gas-tank/

Awww, but when I were a lad you could pick one up for five bob!

Yes they are beautiful tanks. To expensive for me, so I’am back to try to determine which (if any) of the India tank suppliers I should order a steel tank… still hope someone with prior experience can advise about their quality… are they basically all the same? emco who reportedly has better quality doesn’t seem to supply fastback tanks…

I posted this which gives 2 Indian sellers where you will get better service, but they will still need work.

If you want cheap but prepared for work then buy off eBay, Royal Choppers and pummy8081 have good reports but they still come from India so buy bare steel. Once the prep work is costed you may then in total pay the same as RGM.

I cannot comment from experience, but reading about these on this and other websites, the quality is mixed to say the least. As I understand it, they are of course hand-made and not pressed as the originals were: this entails using several pieces welded together to get all the basic curvatures of the outline shape in, rather than just a base and a top section- make up your own mind on that point!

Even a skilled English Wheel worker would have problems getting that from a single sheet.

Sounds like a 'good trick' and possible quite straight forward, until you come to the bit- Discard the water somewhere - it's contaminated so not a public sewer. Where/how? I just cannot see a responsible easy way to do this. But an interesting 'desk' exercise.

Ethanol-Do I lead a sheltered life? I use an Electra (all original bits) and a Reliant on petrol on the road-never had an issue with fuel! I didn't mean to change the subject but hey ho it is interesting.

I also have a '68 Commando which I have been running with a Caswell treated tank for the past ten years. It's still fine, but if using this product you must take great care with the prep.

For steel tanks I use POR 15, which is also exellent provided the same care is taken with it's application.

On the subject of alternative tanks, Holtworks was looking for people to express intrest in the early badge version so he could make a batch.

Martyn.