Boxerworks.com

G’day all. I’ve just acquired a new tank for the mighty R80g/s. A rare 45 litre Heinrich (by Theofried Jekel) ….. massive, in great nick. Inside, the tank is unlined, not coated and by torchlight through the filler, has a very, very lite surface rust. After treating the rust I’d RedKote the inside before use. How would you go about rust treatment? Vinegar? Proprietary rust killer? What’s the current wisdom?
Thanks in advance. Hools

POR-15.
https://por15.com/products/motorcycle-f ... repair-kit

I used this kit about 30 years ago on my R90s and it still looks fantastic with zero internal degradation.

I would stay away from the old KREEM products, which did not adhere to the metal in some other tanks I've sealed, leaving a placenta like wad of crap inside the tank.

I used vinegar to remove old BMW lining and kill the rust. I just filled the tank and left it for a few days. I rinsed with water (possibly would have done well to add a spot of baking soda), dried it as well as possible, and used a tank coating system by Caswell Plating.

It's been 10 years and it's all holding up well.

Most tank coatings are of questionable looooong term durability, even when professionally applied.
Unfortunately in some cases they are the only viable option to save a severely rusted (rusting?) tank.

If your tank only has only "has a very, very lite surface rust" as you stated, just clean it out and leave it uncoated.
I've seen too many 'coated' tanks cause debris in the petcocks, filters and carbs and would not necessarily recommend coating it in this case.

Be sure to drain it well and disassemble and clean petcocks so there are no water pockets stagnating in its lower crevices.
From then on, it will never rust if you regularly keep it full of gas. A few ounces of methyl-hydrate (gas line anti-freeze) added to a full tank will prevent any possible water condensation during prolonged storage.
If you must store it empty, like in your basement, spray it liberally with WD-40 and just rinse it out with gas before putting it back into service.

Thanks everyone! I had considered just cleaning and using GSPD, as the rust is really only a dusting over otherwise bright metal. I reckon Melville’s vinegar treatment, a flush and use thereafter is where I’m at!I’ll monitor and decide on a coating if required. The RedKote info was great! Thanks PAS!