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Fuel Tank Leak

Discussion in 'Norton Motorcycles (Modern)' started by gchoppin, Sep 17, 2019.

  1. gchoppin


    Sep 26, 2017
    I know there have been numerous threads regarding fuel tank leaks but here's a new one. My '14 sport began to leak fuel about a month ago. It was dripping from the bottom of the tank next to the pump while on the side stand. The tank was wet near the pump so I assumed I needed a new "O" ring. Installed the replacement ring (50 buck) but still had a leak. Removed and tried a different sealant but the tank continued to leak. As I began to think through the issue I remembered the paint was starting to peal on the tank bottom where the overflow drain passes through the tank. I also remembered that the tank did not leak until I completely filled the tank. Added about two gallons after the seal replacement and no leak. Filled the tank and its back to leaking. I removed the tank and found that the tank is leaking fuel from the overflow exit hole on the underside of the tank. I sent a camera inside the tank and it appears that the tank is built with a long brass coupler nut as the channel from the top of the tank to the bottom exit holes for the vent and overflow tubes. I can see the brass coupler nut through the plastic and there appears to be a crack in the plastic around the nut at the bottom of the tank. I posted pictures of the decals on the same tank bubbling several months ago. Glad I didn't waste any money repainting a tank destined to leak. I've purchased my first motorcycle in 1973 and have never stopped riding. I can recall owning 18 bikes so far and never have I had to replace a fuel tank. Seriously, this bike has never even been rained on much less left out in the elements. Climate controlled storage for the most part.
    Anyone else heard of this issue. I may try a plastic gas tank repair kit but I would hate to repaint it and have it start leaking again. Also not interested in blowing myself up when the gas hits the exhaust.
  2. BritTwit

    BritTwit VIP MEMBER

    Aug 25, 2009
    Man that sucks.

    The only tank problems that I’ve heard about are:
    1. The tank flange that the gasket bolts to is too thin and flexes enough to leek from around the fuel pump seal
    2. The ethanol in the fuel causes the tank to distort/deform in shape
    3. Blisters on the tank surface. I experienced this on my original tank. The bike was still in warranty and factory replaced it free of charge.

    Leaking from the tank underside is serious business, and I wouldn’t trust any sealer in that area.
    Seems to me for peace of mind the tank’s gotta go.
  3. Britfan60


    Jan 5, 2014
    I recently posted that the two black rubber fuel lines were so stretched out they virtually fell off. Snip a 1/4" off and reapply. Also, the gas that leaked out immediately took the paint off the bottom of the tank. It bubbled and peeled within seconds. Heavens forbid they spray the bottom during manufacturing.
    Sorry for not taking and posting photos.

    Also, isolation to prevent damage from vibrations on these bike is minimal. Things crack.
    Last edited: Sep 17, 2019
  4. TonyA


    Jan 16, 2015
    Time for Alum Tank ?
  5. Al's#5


    Feb 4, 2020
    Trying to get my head around the water/ethanol problem with the Ascerbis composite tanks. My CCM Spitfire has a composite tank from Ascerbis and approaching 2 years, no probs. Both my CCM tank and my 961 unit appear to have plastic/polymer inners, if so any probs should only be with attachments etc. Living in hope!
  6. comet

    comet VIP MEMBER

    Aug 23, 2016
    I've had my Norton tank for 7 years and it's still ok. I buy ethanol-free petrol whenever I can and I drain the tank each winter. I think it's the draining that probably makes the most difference as I understand that it's water that distorts the tank, the ethanol exacerbates this by causing more water to be absorbed into the petrol.

    When I was at the Norton factory a few years ago I was shown a couple of bikes in the service area where the tanks had expanded and were butting against the oil filler tube at the front. I had asked the technician why the nuts holding the seat couldn't be fixed in position and he showed me these bikes, saying that the seat position had to make allowance for the tank expansion. That explanation suggests they knew it would happen and I'm not totally convinced, but there was no doubt that the tanks had expanded.

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