New steel tank coming, any tips?

Manu · Wednesday at 9:45 PM

Hi - I have a EMGO steel roadster tank coming from CBS to replace the decaying fiberglass tank on my newly acquired '72. My often lying AI buddy tells me I should:
1) degrease the tank with acetone or lacquer thinner
2) Etch with white vinegar or phosphoric acid
3) Dry really well
4) Roll Caswell epoxy around for 20-30 minutes then drain.

After all that get it painted.

What do you guys think? Is this all a good thing to do? will the epoxy just decay after a while?

Thanks

robs ss · Wednesday at 9:51 PM

This will probably be a "best oil" thread but...
I believe in keeping it simple and prevent rust by ensuring the tank is full(ish) when parked. Empty tank can rust.
I have a couple of fuel containers at home to make it easy to do that.
On used tanks I start off by using a CRC product called Evapo-Rust - seems to work well without leaving a lining behind.
I'm sure linings can be good but they have gone badly!
Cheers

johnm · Wednesday at 10:08 PM

I'd check the tank for leaks and then give it a rust etch. But I'd never epoxy a new tank. I used POR 15 on my 40 year old rust inside original tank about 7 years ago and it's worked perfectly. But I would leave well enough alone on a new tank.

kommando · 2026-05-14T03:16:57-0600

The problem with a resin liner is what works now may not in the future, petrol make up changes with the seasons and regulation.

Phosphoric acid on clean steel will form a protective layer of iron phosphate, its an improvement on bare steel but not as good as zinc plating.

Matchless · 2026-05-14T04:43:25-0600

From what I've read about the Emgo tanks, there is no need to line them. They are a quality item, & every bit as good as the original Homer tanks, unlike the Indian made ones, which are variable to say the least.

Café au Lait · 2026-05-14T05:28:22-0600

When Matt built my bike for the original owner back in 2013 he retained the original tank and lined it with Caswell epoxy. Upon receiving it in 2024 I noticed that the lining had detached from the arch in a large sheet but he assured me nothing will come of it and so far that’s been true. However, a couple of months back my tank prong a very minor leak from a crack in the stud bushing.

This is where the lining truly become problematic as it won’t like the heat from welding and I’ve been advised that doing that may fragment the liner material enough to foul the fuelling. My only resort was to use JB Weld and seen how long I have before major surgery.

If I needed a new tank I certainly wouldn’t line it.

I’m riding to Pescara, Italy in 3 weeks time and will definitely be armed with tools and JB Weld

kommando · 2026-05-14T05:33:55-0600

Those studs make the whole front mounting not vibration free, best to use the rear silencer mounts with the 5/16 studs on both ends with 100% rubber between them..

trident sam · 2026-05-14T05:53:02-0600

I've had a couple of Emgo steel tanks, they are superb and in my opinion better than original. I would not coat the inside with anything

Grandad · 2026-05-14T06:31:02-0600

All I'd do is put a tsp of 2T oil into a full tank so it is always lubed and can therefore never rust ( unless left for years of course ), you won't have any smoke or fouling with just a teaspoon full.

concours · 2026-05-14T06:38:22-0600

kommando said:
Those studs make the whole front mounting not vibration free, best to use the rear silencer mounts with the 5/16 studs on both ends with 100% rubber between them..

I left the studs in place, and use soft, rubber washers, a shouldered rubber cushion to isolate the stud from the hole, a fender washer and a Nylok nut barely snug. Allows for some movement without putting any stress/strain on the studs. It has worked for 50 odd thousand miles.

I concur, the exhaust bobbins are a good choice to keep the tank from cracking near the weldnuts.

Café au Lait · 2026-05-14T10:35:52-0600

kommando said:
Those studs make the whole front mounting not vibration free, best to use the rear silencer mounts with the 5/16 studs on both ends with 100% rubber between them..

Unfortunately that wasn’t really an option for me as to remove the stud would in all likelihood make things worse so I went with stabilisation instead.

I’ve experimented with different numbers of rubber washes and 5 is what suits my bike, any less and the washers don’t make contact with the mounting plates and any more and the nylock nuts back off, I lost one this way.

So with 5 rubber washers I’ve used 2 new nylock nuts with plain washers and tightened only to the point I can’t spin the metal washers. Then if I lean gently on the tank the washers can just rattle when tapped.

I am tempted to fabricate my own washers from sheet Sorbothane which is far far better at vibration absorption than rubber but may end up too soft over all so maybe just 1 or 2 per stack

Manu · 2026-05-14T11:15:02-0600

thanks for the responses. My bias was to not line so will stick to that. Grandad's Idea of oil sounds good. I had someone recommend Marvel Mystery oil. I live in a very dry climate which might help with rust as well. Protecting those front studs is a great idea as well.

How do you guys check for leaks? Just fill it with fuel and see what happens? Air?

kommando · 2026-05-14T11:17:39-0600

Café au Lait said:
Unfortunately that wasn’t really an option for me as to remove the stud would in all likelihood make things worse

Your thread insert has already started to depart so you have not real choice but to leave the current stud in place. But if you ever get it properly welded back into full contact then use the silencer rubber. @concours solution will also work but the next owner will probably overtighten the nyloc nut and then back to departing inserts.

Café au Lait · 2026-05-14T12:04:45-0600

The bobbins on that black tank look way too short to me

kommando · 2026-05-14T12:08:20-0600

Café au Lait said:
The bobbins on that black tank look way too short to me

They have a rubber washer underneath which as well as making them higher stops that end stud bottoming out, the outer stud can take more rubber washers to take the tank even higher. When you have like I do a frame with the two brackets they mount having a difference of 1/4" in height using the stock amount of rubbers is not an option anyway.

zotz · 2026-05-14T13:42:43-0600

Manu said:
How do you guys check for leaks? Just fill it with fuel and see what happens? Air?

If you do that don't use any more than 4psi or better yet lung power unless you want a basketball shaped fuel tank.

Tornado · 2026-05-14T14:03:43-0600

zotz said:
If you do that don't use any more than 4psi or better yet lung power unless you want a basketball shaped fuel tank.

Just connect a bit of hose to a fuel tap, put a rubber glove around the filler cap with elastic bands or tape etc, then blow into hose...close tap once glove inflates....check all seems with soapy water or kids bubble liquid...lungs are plenty good enough to give a little positive pressure in tank.

Tornado · 2026-05-14T14:06:12-0600

Uncoated steel tanks last decades on our bikes if not left in damp partially full of fuel. My reprop tank from Pakistan is holding up just fine after nearly ten yrs of use...even with the dreaded ethanol fuel. No rusting.

cliffa · 2026-05-14T14:26:06-0600

Manu said:
thanks for the responses. My bias was to not line so will stick to that. Grandad's Idea of oil sounds good. I had someone recommend Marvel Mystery oil. I live in a very dry climate which might help with rust as well. Protecting those front studs is a great idea as well.

How do you guys check for leaks? Just fill it with fuel and see what happens? Air?

I use a party balloon to block the filler neck, then fit both taps, close one, blow into the other then close it whilst holding the pressure.

Post in thread 'Tools You Have Made to Maintain your Norton'

Jan 14, 2024

I wanted to pressure test an interstate tank before listing it for sale, but I had no way to seal the filler neck and didn't want to make up something specifically for it, so I had a think and came up with this idea...
It's a party balloon, blown up whilst halfway inside the tank, and then held in place with a strip of masking tape to stop it popping out when pressure was applied. It worked like a charm, and no leaks were detected.

Lineslinger · 2026-05-14T20:19:25-0600

Good observations in this thread.
My original tank sat for 42 years empty. And the rust inside of it was progressing well. I had to send it out for an epoxy lining. I chose a bad vendor, it was an extensive process and I often wondered if I was going to get my tank back. I should have sent it to cNw
I also had an original interstate tank with side covers and an original roaster tank with side covers that I found at an estate sale from a physician who was a Norton nut. They were still in the original packaging as sent from England.

I have solid rubber insulation/buffer for vibration protection at the four fastener anchor points,but I may back the nylocks off after considering what I've read here.
I also wrapped the center spine with 3/8" closed Cell neoprene. The tank slipped into position with a very snug fit. This neoprene wrap carries the load of the tank while the four fasteners simply hold it in place.
The neoprene is a great damper and eliminates almost any vibration.

New steel tank coming, any tips?

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