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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: blackie1 on January 27, 2024, 04:44:29 PM

Title: oops i have a leak
Post by: blackie1 on January 27, 2024, 04:44:29 PM
hole in tank.
the search for best repair starts now.
first time i have had to do this repair.
Title: Re: oops i have a leak
Post by: The Mighty Gryphon on January 28, 2024, 10:13:29 AM
Remove the paint around the leak and clean well with rubbing alcohol after scuffing with 180 grit paper.  Then press some JB Weld into the hole and onto the surrounding area going about 2cm from the hole.  No need to put the JB Weld on too thick, a couple mm is all it needs as long as you are bonding to a clean roughed up surface.  I have successfully repaired several fuel tanks with the method.
Title: Re: oops i have a leak
Post by: Duckbubbles on January 28, 2024, 10:47:49 AM
And after plugging the hole I had with JB Weld or some epoxy, I used a product called Kream to coat the inside bottom of the fuel tank, particularly the "V" section where the top and bottom are welded together.  Didn't do the whole tank like they recommend, just the bottom.

Frank
Title: Re: oops i have a leak
Post by: Laitch on January 28, 2024, 02:11:40 PM
The original JB Weld has worked as a hole patch when I've used it. I've let it cure for up to a week beyond the recommended curing time.
Title: Re: oops i have a leak
Post by: Chaos on January 28, 2024, 02:28:49 PM
I've used JB and various epoxy tank patches, best results were with letting it cure for a couple days.
Title: Re: oops i have a leak
Post by: blackie1 on January 29, 2024, 02:04:35 AM
thank you very much for all your replys.
on the exterior, as advised i will clean up holed area and patch with JB weld.
that sounds straight forward.

what to do for the interior?
can i treat the inside with rust killer?
if so do i need to remove fuel pump etc before rust treatment?
Title: Re: oops i have a leak
Post by: The Mighty Gryphon on January 29, 2024, 07:57:18 AM
I wouldn't bother with the interior.  As long as the bike gets used regularly, and the fuel doesn't sit in it for years at a time, corrosion shouldn't be a problem.  For long term storage(>1 year) either fill with non-ethanol fuel or drain the tank and fuel system completely.  And don't store outdoors in the weather.
Title: Re: oops i have a leak
Post by: blackie1 on January 29, 2024, 10:33:52 PM
cheers Gryph  112350
it does go for a run most sundays
i will post a pic of my hole repair once it is done.
unless it looks like crap ....
Title: Re: oops i have a leak
Post by: Laitch on January 30, 2024, 02:52:55 PM
it does go for a run most sundays
Unless you're burning through the entire tankful on Sunday, blackie, I suggest adding fuel stabilizer (https://www.supercheapauto.co.nz/p/sta-bil-sta-bil-fuel-stabiliser-236ml/223945.html) to the tank at fill-ups even if you aren't using E10—58ml at fill-up from empty or fractions thereof when topping off. It will help keep the gasoline and water from separating, and control varnish and fungus buildup. Idleness is the devil's playground, fuel tank-wise.  :laughing4-giggles:
Title: Re: oops i have a leak
Post by: blackie1 on January 30, 2024, 10:49:55 PM
thanks Laitch, even a link to my local store. what a legend.
Title: Re: oops i have a leak
Post by: blackie1 on February 03, 2024, 04:30:14 PM
cleaned up around the hole with the most coarse emery paper I had on hand then gave it squirt of brake clean prior to applying the JB weld.
will let it cure over the next week.
i might later apply another bead of JB weld in that area just along the seam of the tank.
Title: Re: oops i have a leak
Post by: blackie1 on February 03, 2024, 04:31:44 PM
pic 2
Title: Re: oops i have a leak
Post by: blackie1 on February 03, 2024, 04:32:48 PM
pic 3
Title: Re: oops i have a leak
Post by: blackie1 on February 03, 2024, 04:33:45 PM
pic 4
Title: Re: oops i have a leak
Post by: blackie1 on February 03, 2024, 04:34:34 PM
pic 5
Title: Re: oops i have a leak
Post by: blackie1 on February 03, 2024, 04:35:31 PM
pic 6
Title: Re: oops i have a leak
Post by: blackie1 on February 03, 2024, 04:37:05 PM
pic 7
Title: Re: oops i have a leak
Post by: blackie1 on February 03, 2024, 04:40:04 PM
fuel stabiliser which i will use in future
Title: Re: oops i have a leak
Post by: The Mighty Gryphon on February 04, 2024, 08:41:00 AM
Nicely done! 
Title: Re: oops i have a leak
Post by: blackie1 on February 17, 2024, 03:53:22 AM
tank is back on bike and full of fuel. no leaks.
in this picture you can see the foil heat shield and the matting beneath the foil is pulled back.
due to the fuel leaking in this area it  has dissolved the adhesive that kept the matting and foil stuck to the underside of the tank.
i initially do not "re glue" this before putting the tank back on the bike because i thought it would stay in position. but the wind gets in there and after a test ride it hung down and could be seen poking out slightly beneath the tank.
so i thought i would put a couple of drops of superglue (as i had a tube) on that loose bit to hold it in position.
i put a couple of drops of glue on the matting material and within about 2 x seconds a tendril of smoke rose up and i could feel it becoming very hot.
gave me a hell of a fright.
did not last long maybe 3 x seconds) and did not ignite into a flame thankfully.
i went inside and googled " superglue on matting causing heat" and it spat out this......
"there can be extreme heat produced when superglue reacts with cotton, wool, and sometimes leather. Heat and occasionally even smoke and fire can be produced when cyanoacrylate adhesives come into contact with natural fibers, particularly cotton and wool."

I never knew this.
anyway it did stick  so guess i got lucky