Gas Tank bubble and boil... anyone else have this issue?

Energy One

Fat_Bastard

Active Member
YES!
If caught in the early stages --it can be saved!

If let go -- well you see what happens...
Take that gas cap flange off and see what is under there; and never do it that previous way again!

Looks like you gotta repaint the whole tank to make it nice again...

Check it out:
http://www.bigdogbiker.com/threads/install-repair-gas-cap-paint-saver-bubbling-paint.78828/

I had the misfortune of getting an expensive custom paint job by so called experts that failed miserably within days; from paint bubbles around the gas cap.

This was caused by gas or gas fumes getting under or between the paint and underlying metal gas tank because the rubber gasket was used improperly, with improper adhesive.

To properly fix it in my case:

1) Remove the stock Landmark gas cap



2) Remove the stock Landmark Paint Saver Ring screwed into the gas tank with the SPECIAL Landmark REMOVAL TOOL (not shown).



2a) Landmark Removal Tool




3) In my case the Landmark paint saver ring was installed incorrectly with the rubber gasket (badly worn and not the same style as provided by Landmark) see photo below.




4) Clean up any loose material and block pieces from falling into tank with tape…



5) Re-attach loose paint bubbles with crazy glue equivalent; I used XBon super glue; other products may work as well (no luck with clear nail polish as some suggest). Wear rubber gloves in case you smear and get fingers stuck to paint, tank, etc…

6) Contact: “MR. Wright” of this Forum to have him custom make you an oversize paint saver ring to fit your situation out of stainless steel stock. (about $35.) see below lower right in photo.



7) Dry fit all to be sure of the look and fitment, bend, etc, will work…

8) Place masking tape around area to cover where you do not want RTV silicone to go and keep it neat.



9) Assemble with RTV Silicone glue (I used clear) on the gas tank threads and top edge; then put RTV Silicone on underside of large MR. Wright ring. Place on tank wipe excess oozing off inside of tank; masking tape dam will block from falling into tank.

10) RTV silicone up the smaller Landmark threaded paint saver ring and screw in to tank threads through center of the larger MR. Wright paint saver ring. DO NOT USE THE RUBBER GASKET! Or it will leak…



11) Tighten Landmark paint saver ring with tool to very snug fit or in my opinion what would be about 30 ft. lbs. of torque. The RTV Silicone will ooze out everywhere --a good thing, and wipe excess to clean up.



Recommend: WAIT 3 FULL DAYS TO DRY WITH TANK GAS CAP OFF, NO GAS IN TANK ! in well ventilated area.

After that gas up; never fill past inside metal lower neck of tank. (As I knew from my early teens on any bike-- and you probably do too).

What I like:
The new larger Mr. Wright paint saver ring prevents scratches in paint from finger nails and gas nozzle flex boot (in California gas pump nozzles) may scratch paint.

This fix has worked now for 4 months and 10 tanks of gas. A lot less expensive than new paint and I believe it is a much better set up than stock.

I have seen this done with the Kuryaken gas cap set up as well both look very nice!

PS: side experiment: I took a thumb nail size blob of Permatex RTV silicone after 4 hours dry time and drenched it periodically in gasoline over the 3 day wait; it never decomposed, compromised or damaged it... AMAZING!

I also bought a brand new Landmark Gas Cap (vented as original) with paint saver and removal tool included ($95.) Got it in one day since Landmark is in Oceanside, California 20 miles down the freeway.
http://www.landmarkmfg.com/

Gas Cap dis-assembled below to show vent and inspect...




PS: the above repair done Nov. 2016 and as of June 4, 2019 all working great!
31 months now and at least 70 tanks of gas...
 
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Fat_Bastard

Active Member
...hmmmmmmmm...
I zoomed in on your "stock flange" and it appears to be machined different than mine. My photo of the 2004 version (shown first is slightly "bumpy", worn on the inside bevel) is identical to the 2016 new Landmark flange photo (shown later installed; except with new flat bevel)...

It "appears" to me that your upper flange might be "different", in multiple parts, with a seam or ridge; or do I need my glasses...? :oldconfused:
Let us know when you take it off.
 
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BigDogRick

Active Member
This is precisely the "fix" we are doing right now on my 2000 split tanks. My tanks also show a surprisingly thick bondo layer that has actually masked the delamination and rust intrusion along a significant length of my tank resulting from a tiny slit in the paint coating that occurred eight years ago. Obviously, that means I left a blemish unrepaired for a very long time. What is surprising is that the fuel could travel so far without showing true bubble for seven years. The bubble that could be depressed with my finger just showed up last year. I have been planning to repaint my bike for three years and have not found a scheme that I was satisfied with until now and have started removing the blemish only to find about 25% of the tank surface delaminated and corrosion starting on the bare metal. I have the oversized trim rings from @Mr. Wright and have the new paint saver/caps. @Roaddawg is doing the repair and repaint right now.
 

Roaddawg

Well-Known Member
Here is what Ricks tank looks like. This is the top where the bondo was "thin".



This is the bottom of the other side. The paint was still intact but had lifted from the surface of the tank along with the bondo, due to the rust. Most likely the tank had some rust and they bondo'd over it.



There was a spot on the end, that I will post later, that had at least 1/4 inch of bondo. I have never seen so much bondo used.
 

Fat_Bastard

Active Member
Here is what Ricks tank looks like. This is the top where the bondo was "thin".

This is the bottom of the other side. The paint was still intact but had lifted from the surface of the tank along with the bondo, due to the rust. Most likely the tank had some rust and they bondo'd over it.

There was a spot on the end, that I will post later, that had at least 1/4 inch of bondo. I have never seen so much bondo used.
Bummer for us with this problem...

Many things can cause it:
bad paint, scratch, crack in paint, over fill gas tank, spill gas on tank, improper gas cap vent, rust... etc.
If gas, gas-fumes, rust, "or any foreign matter" get under the paint, primer or bondo, etc... that paint is blistering, bubbling and coming off. period full stop.

To help solve this problem:
I hope others can see/understand that a 'rubber gasket alone' under the 'screw in flange' with nothing else -- on a Big Dog style tank will fail as above...
It will never seal it properly.

I maintain that the paint must be glued/sealed down to the tank metal at the "exposed edge" where they meet and after that; RTV Silicone must be used all over the place to the point it oozes out everywhere in lieu of the rubber gasket to get a "custom even pressure distribution gasket."

Hope you never have this problem again and someone fixes it right! :cheers:
 
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Hirter6Pack

Not Quite A Guru
Lifetime Supporting Member
Supporting Member
I think one of the key elements to a good paint job is the prep work. Clean very clean and allow for drying time. You can't cover anything up, your last coat is only as good as what's underneath.:2cents:
 

Mr. Wright

Guru
Lifetime Supporting Member
Supporting Member
Good afternoon mr. Wright. I'm having a similar issue on the tank I inherited from my dad. Are you still making the oversized rings?
Yes. First thing you need to do is go up to the top of the page and click on forums, click on introduction and do an introduction. It's only polite when joining a forum. When this storm is over and I can get on my computer, I'll send you a link, so you can get ahold of me.
 
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