De-rusting R25/2 Tank

[pmtremblay]

I don't know. I rinsed out the Evaporust with a few good sloshes of gas, and have just keep the bare metal tank filled with non-ethanol. That's been functionally good enough, no rust has returned. If nothing else, Evaporust is a simple and clean first step.

[Darek1967]

I just de-rusted, stripped old liner and recoated my R100 tank. Used Evapo-rust to remove the rust - this stuff is fantastic. Left tank half filled for a day, occasionally flipped the tank to different position. Once rust was gone used very hot water with cleaner/ degreaser to remove old red coating over the course of 3-4 hours, changed water/ degreaser every time it got cold. After 3rd time entire red liner was gone, then used POR-15 kit to seal the tank.

[schrader7032]

Thanks for the details. My tank doesn't have any liner in it. When I got the bike the tank had been repainted and it was bare steel inside. I guess they completely stripped the tank before painted. My bad for not jump on putting a lining at that time. As I mentioned, I couldn't get the petcock off at the time...as it is, it took days/weeks for me to get it off this time. I plan on using Caswell's kit for sealing the tank.

My issue now is I can't find a decent way to plug the fuel filler area as well as the tank outlet. I saw earlier someone mention use of a flexible PVC end cap...but it's all wrong dimensionally. The OD of the tank filler area is a little over 3 inches but that "3 inch" flexible cap has an ID of about 3.5 inches in order to fit over a Schedule-40 3-inch PVC pipe. So, I'm still trying to figure that out.

As for the outlet, I'm finding it difficult to locate a M16x1 nut. It's difficult enough to find M16 but the fine threads are tough. If I can find one, I'll have a friend spot weld a flat piece of steel across one opening and stuff a gasket from an old inner tube to help with the seal.

I'm still on the hunt though.

[Darek1967]

As an outlet plug use wine bottle cork, sand it down to proper size on bench grinder. Fits like a glow without any leaks. For inlet you can try to get a "Fernco" reducing coupling at Home Depot or plumbing supply, where is a 3x2 flex coupling that you could trim to fit your tank.

[therealkennyboy]

My local Ace Hardware carries tapered corks in various sizes, back in the hardware bins area, in a specialty cabinet. Both natural corks and rubber corks. Might be worth a look?

[Flx48]

Hi Kurt-
For gas cap I've used cling wrap, sandwich bags, or rubber gloves under the gas cap, depending on what was on hand, and what liquid was being used, (how worried I was) with the gloves from the parts washer being used when most concerned.
Not had any paint issues using Evaporust or CLR when cleaning/derusting the insides, though one might want to do a discreet test if inclined, never know when the formulas might get changed.
(I use CLR on the frame and tin if there is rust present, but it must be rinsed off in a timely fashion, and it will only lift the paint where the rust extends under it)
With the petcock hole, as Ken suggested, hardware stores always carry multiple sizes of black rubber bungs; I prefer using the size that fits a good three quarters of the way inside the petcock fitting.
And with the balance pipes on the bottom, I use a piece of gas line that's not destined to be returned to service.
Best-
George

[schrader7032]

Certainly I've considered corks but I was hoping for something more secure. I can see me moving the tank around and dislodging the cork....ouch! And the cork won't work on the tank inlet due to the cutouts for the cap mechanism. Something under the gas cap...wouldn't it get cut the first time the cap was inserted? There are plenty of the proper style gas caps on Amazon but there aren't enough in the way of dimensions to say it would work.

There are no balance pipes/tubes on the R25/2 tank. The back of the tank is essentially flat, no hump like on twins.

[Flx48]

Hi Kurt-
To your points, I've found the smaller black corks a more secure fit than the larger when screwed down in, (why I mentioned) and I generally put a finger on them when doing the shimmy and shake dance, and they've not been an issue.
Sandwich bag or glove or whatever under the gas cap; have not had an issue with the cap cutting it 1st time used, (or 2nd or 3rd) but of course testing what happens for yourself is prudent.
I brought up the balance pipes because others may also be looking at the thread with an eye to tackling their tanks for the first time.
The chemical glove shown in the pic is installed under the gas cap did not tear, and is happily back on duty in the parts washer.

It's natural to gravitate to belt and suspenders with things we don't do every day, think we're all that way.
Just experiment and see what you're comfortable with; water is benign and you're going to clean the inside anyway, and the things suggested are easily available and cheap.
Folks on the thread are generally giving you thoughts of what's worked for them, and you'll lean toward what feels like it's in your comfort zone.
Best-
George

[schrader7032]

Thanks for the perspective, George. I know what I want to use to seal the tank off, but since I'm having trouble getting there, I'll have to consider alternatives as mentioned here.

[VintageJim]

It looks like this site has the M16x1 nut that Kurt was looking for.
https://www.fastenal.com/product/details/11509286
Jim