Fixing a leaking IMS tank

I got an awesome deal on an IMS 4.7 gal tank. As with most great deals it came with a catch. The previous owned overtightened the sump fitting and it leaked. This is the story of my attempts to fix it. My guess is that others have had the same problem........

The IMS product support folks grudgingly admitted that this is not an uncommon problem. The sump fitting is used as an anchor for the low-point fuel hose in the wings of the tank. It's simply screwed into the plastic with tapered threads to effect the seal.

Who's idea was THAT ? Why they didn't just mold in a brass female fitting is best left to another thread. Researching the issue here, on AdvRider and ThumperTalk revealed that most repair stories involved tanks with cracks or holes. Nothing about bunged-up threads. I found 2 fuel compatible thread sealers; Permatex Aviation Form-a-Gasket and a rubberized aircraft fuel tank sealant. This is essentially a fuel compatible RTV, and was my choice.

I applied a practice coat to an area beneath the tank and it adhered as well as can be expected to the Hi Density Polyethylene. It was sufficiently rubbery to fill the area between the bad threads and the fitting.

I applied a thin coat to the male and female threads, then built up a filet around the head of the fitting.

The stuff cures in 7 to 10 days ( ! ), so no leak check until next week.

Given the safety issues of a fuel leak onto a hot engine, I plan an overpressure test for a couple days before mounting it up on the bike. Film at Eleven, as they say.

thanks for the write up. I've got the same problem and have used thread tape to fix it - but I fear it's only temporary since the tape I used is just plumbing stuff and probably not fuel resistant.

I believe IMS' new tank has molded fittings and a different "well" where the fuel pump is (one that doesn't drain fuel away from the pump) - but that doesn't help all of us who bought the original.

I had the same problem with my tank too, I just used a whole bunch of thread tape and it hasn't leaked since then.

Here is what they have on the new tanks, an insert for the bung to screw in:

It's been 7 days since the sealant was applied. I decided it's time for a leak test.
I filled the wing with gas and let it sit for 24 hours. No leak ! While it's not a full positive
pressure test I have enough confidence now to mount the tank up. Think I should
swap-out a new fuel pump before the installation ? The 08 fuel pumps seem to have a higher
failure rate than 09 and later. It would really hack-me-off to put the whole thing together and
have to replace the OEM pump shortly thereafter.

If you have a new pump sitting on the shelf awaiting a failure, then you have a questionable pump in the tank and a new one on the shelf.
I would rather have a new pump in the tank and a questionable one on the shelf.
More peace of mind.

Besides, everything is ready for the swap now.

No time like the present, and all that



You know the '08 is gonna fail this summer.
On a ride.
And you're gonna have to be rescued.

Maybe She Wolf will rescue me......

47une wrote:

I had the same problem with my tank too, I just used a whole bunch of thread tape and it hasn't leaked since then.

Here is what they have on the new tanks, an insert for the bung to screw in:

I have been pondering whether it would be a good idea to preemptively give the bung some attention prior to installing my new tank, I guess I have no choice now

Curiosity got the best of me and I decided to have a look at the bung/tube connection. Apparently the tank I ordered a couple of weeks ago hadn't gotten the upgraded bung insert. If you haven't already seen the hardware, here's what it looks like.

The tank has been installed and partially gassed to check for leaks. Dry as a bone, fortunately. The sealant doesn't seem affected by the gas and the non-sealed left side is high and dry too.


Now that it's all mounted up with a new fuel pump, it looks pretty good !


The rest of the parts have arrived, including the Rick Mayer seat, Wolfman racks, rear rack and Cycra Pro-bends. I spent the last 2 days mounting everything up and voila!......the WR250RAdv. Ready to roll!


I took quite a risk buying a tank advertised in eBay as "leaking", but in the end it seems to have worked out fine. I must recommend this sealant to anyone who has this problem. It should have been included in the kit from IMS in the first place.

+1 on the thread tape (use the yellow stuff). Been running it for 6 mo and no leaks since.

Teflon tape works well when the threads aren't buggered. Problem with the original tank is that if the bung is simply tightened to stop the leak you end up striping the plastic female threads. I can't believe that a company who has made SO many tanks would allow that kind of design. It falls into the YGTBSM category. When I spoke to them on the phone they reluctantly admitted that this has happened many times. Still they didn't have an answer to the "which sealant" question. It was like they hadn't even considered it. Very little on TT either. THAT is why I started this thread. My guess is that someone else is in the same boat I was (even though I bought the tank for $50 knowing the threads were fubar).

Jdcooper wrote:

The tank has been installed and partially gassed to check for leaks. Dry as a bone, fortunately. The sealant doesn't seem affected by the gas and the non-sealed left side is high and dry too.


Now that it's all mounted up with a new fuel pump, it looks pretty good !


The rest of the parts have arrived, including the Rick Mayer seat, Wolfman racks, rear rack and Cycra Pro-bends. I spent the last 2 days  mounting everything up and voila!......the WR250RAdv.  Ready to roll!


I took quite a risk buying a tank advertised in eBay as "leaking", but in the end it seems to have worked out fine.  I must recommend this sealant to anyone who has this problem.  It should have been included in the kit from IMS in the first place.

5 years later, are there any updates to this thread? I have the same leak in my IMS tank, and want to fix it with either the Permatex or the Teflon tape. Any updates would be wonderful.

srileo wrote:

5 years later, are there any updates to this thread? I have the same leak in my IMS tank, and want to fix it with either the Permatex or the Teflon tape. Any updates would be wonderful.

If you got the tank new, contact IMS; they will warranty it and send you a new one.