Slight gas tank leak

[Bokobob]

Ok, dealer worked on bike today (1987 K75) and it has a slight leak near the front of the seam on the left side bottom of gas tank.....Please advise if there is a potential fix and if so, any preferred fix-it place to ship the tank to..  Also, if not fixable, should I buy new or used?  Don't want to throw money away, but if need be am in a position to buy new....

Thank you..

[wmax351]

Used makes more sense than new. They are pretty available.


As to repair: You could use a gas tank sealing epoxy putty. JB supposedly is gasoline proof. They offer a putty as well. Roughen the inside of the tank, and put it there.  http://www.jbweld.com/product/j-b-steelstik/

[Chaos]

Pretty common problem, water settles there and the aluminum corrodes.  I used Permatex gas tank repair on the outside of the tank, on the S model the fairing covers up the patch. Never had the problem until I bought a used tank!

[Fossil]

Look on internet for Caswell products. They sell a gas tank sealer that really works. Good instructions for cleaning and preparation. I used a lb of 1inch drywall screws and wrapped the tank in blanket taped it and then put it in a dryer with additional blankets. Run for 30/40 min no heat and inside surface will be nice.

[jacksdad1963]

Fossil: you have lost me totally, don't understand a thing in your post!  :yow

Just today my tank also leaked: on the left side, just behind the fuel pipes! I read up in the Lieberry, and have found a UK supplier of Permatex gas tank sealer....seems to be the favourite on here  :2thumbup:

[Elipten]

Fossil is cleaning the inside of the tank by tumbling it in a dryer and during the screws to clean up the corsion.

[Motorhobo]

couple more +s for Caswell here...same issue a few months ago.

http://www.motobrick.com/index.php?topic=5382.msg33444#msg33444

[Fossil]

The hard drywall screws will loosen and clean out any leftover corrosion. Remove ALL the screws and then follow the directions included with the Caswell kit. Nice solution and not a budget buster!!

[branandfox]

Just had my lady painted and can attest to the PAIN of a small hole there. I actually had a rather good sized hole about as round as the top of my pinky... NOT FUN. The Previous owner had some kind of epoxy on the hole under the heat barrier. what me and my painter first tried was an aluminum patch with a bunch of JB weld. That seam is not able to be reached without at least taking out the fuel pump which in itself is a fun task AND THEN your hand might not be able to twist, turn, and fit into that little hole. after about a week the JB gave way and I came home from work the gasoline RUNNING down the side of my engine and it had filled up that little area under the fuel tank. not safe either way and not easy to clean up from in there. what we did then was I found a large bolt. I believe a 10MM for my hole and used a dremel with a sanding stone to make the hole a bit bigger and round it out for the bolt. My hole was close to the wall of the tank so then once at the perfect size of barely fitting... I slowly hand torqued the bolt in with 3 neoprene washers and some of this jazzy permatex stuff.

http://www.permatex.com/products-2/product-categories/gasketing/gasket-sealants/permatex-permashield-fuel-resistant-gasket-dressing-flange-sealant-detail

I put the permatex blue on the bolt under the head and all over the neoprene and hand torqued it down as tight as I could get it. then took a wrench and barely torqued it a little more! so far about a month of some goood riding has been done with said patch. the Bolt is slightly threaded into the sidewall of the tank and the hole was made just the right size to accept the bolt and let it create thread on the hole. it is a patch and eventually I will patch it with something more permanent like more hylomar. some JB around the bolt and whatnot and treat the inside of the tank with some cleaner and sealant. DO NOT USE JB THOUGH. It is gasoline but not ethanol proof! Not sure about the generic permatex patch stuff but I would rather use the hylomar permatex blue stuff! good luck man and let me know how it goes!

[jacksdad1963]

OK...I've cleaned up the hole in the tank, then applied a patch of Permatex gas tank and radiator sealer. Then, I coated the inside seams with some leftover POR15 tank sealer  :2thumbup:
Its sat drying now, I'll try adding fuel tomorrow, once everythings had 24 hours to set!

[Bokobob]

Thank you all for the wonderful and helpful replies.......I checked the bike this morning in the garage and  there was no leakage evident along the underside of the seams and I also have all the plastic trim removed (radiator cover and side covers) and then I figured maybe it was because the gas tank had become less full from riding since I took it to the dealer....So, I just ran up to the filling station and added 3.4 gallons of gas to bring it to full again...I rode it home and so far I don't see any evidence of leaking...

It was extremely hot when I brought the bike back from the dealer yesterday afternoon (94 degees F) and this may have somehow had an effect on it...

I'll keep an eye on it and post more if/when I find it is leaking again...

Again thanks..

[jacksdad1963]

Petrol will find a leak no matter how hot or cold it is, its summat due to the 'seeking' ability of a fluid or such shite...way to technical for me but anyhoo....its fixed  :2thumbup: