1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Pressure Testing a New Tank

Discussion in 'Norton Commando Motorcycles (Classic)' started by Tornado, May 17, 2019.

  1. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    Moving forward with plans to get a CS re-production raw steel tank painted up. Have tried a homemade setup to test for any leaks....learned from a YouTube video on a home-build aircraft fuel tank maker showing to just attach a nitrile glove around the filler opening using elastic bands. Then to blow into an outlet nozzle until the glove inflates and leave it to sit overnight. Any significant lose in glove inflation not accounted by temp changes indicates a leak and to then proceed with soapy water spraying on seams/fixtures etc.
    Well, doing this gave glove deflation in only a matter of 15-25 minutes. Tried double wrapping the glove with elastics but no improvement. Went hunting with soapy water but could not see any obvious leaks.
    Any other tips or does it need to go a a radiator type shop for more professional checking?
     
  2. Time Warp

    Time Warp .......back to the 70's. VIP MEMBER

    Joined:
    Dec 3, 2012
    Is the glove made in India ?
     
  3. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    Of course not! I only use the very best Chinizium nitrile gloves.....same place that makes my condoms I believe ;-)
     
    BritTwit likes this.
  4. brokeneagle

    brokeneagle VIP MEMBER

    Joined:
    Oct 30, 2014
    The way I test is to get a plumbers test plug that fits the gas cap opening (1 1/4" I think). Build an air valve from an old petcock and a valve stem or similar. Use a hand pump to put in 4 or 5 lbs, dunk under water and look for bubbles or just a bubble as it doesn't take much of a leak to lift your paint job. DO NOT USE A COMPRESSOR! Much more pressure will blow the tank up like a balloon and it will be ruined. If you take it to a radiator guy, make sure he has done motorcycle tanks before as radiators are tested at higher pressure with no damage.
     
  5. Time Warp

    Time Warp .......back to the 70's. VIP MEMBER

    Joined:
    Dec 3, 2012
    Good advice but would do it yourself to save drama.
    Remember Alan Hodge (sp) did that with the exact same tank, he took a Norton tank in and got the radiator shops rendition of a puffer fish back.

    I believe the tank was not only ruined but leaked anyway so was scrapped.
     
  6. 850commando

    850commando

    Joined:
    Nov 1, 2014
    i found that once i filled them with gasoline the leaks became visible... just fill it since its not a sealed under pressure system anyway.

    as an asside i think that the Emgo reproduction may be better the the CS one? i have seen dissatisfied discussion regarding the CS one. but no personal experience
     
  7. Dean

    Dean

    Joined:
    Jul 26, 2014
    Did the same with a bath plug in the gas tank opening. Used a ratchet strap to hold it in. Then cut down a tyre valve to fit in the petcock and pumped it up with a bike pump until I got the gauge to just move (4-5 psi) then put it in the bath. All good.
     
  8. gortnipper

    gortnipper VIP MEMBER

    Joined:
    Nov 11, 2013
    Put a piece of tape over the breather hole on the metal disc of the filler cap. Put a cap on and peacocks in and close all of them. Fill a bathtub with warm water. Submerge and hold down with one hand on top of the cap to prevent pressure escaping. Look for bubbles. Dry tank off when you are done!
     
    concours, MichaelB and jbruney like this.
  9. baz

    baz VIP MEMBER

    Joined:
    May 26, 2010
    Definitely as stated above no more than 4psi in a petrol tank
     
    concours likes this.
  10. MexicoMike

    MexicoMike

    Joined:
    Jan 31, 2010
    Man, I think those peacocks would be mighty PO'd being inside that tank underwater! :)




    Don't you just love auto-spell? ;)
     
  11. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    Not nearly as PO'd as the Wife if she sees a gas tank in the tub or a ring of slimy grease afterwards! Lucky for moi, she is away for a few weeks....
     
    gortnipper and MichaelB like this.
  12. gortnipper

    gortnipper VIP MEMBER

    Joined:
    Nov 11, 2013
    Yeah, they are noisy bastards as well. Used to have one that lived behind us. Worse than roosters.
     
  13. alan hodge

    alan hodge VIP MEMBER

    Joined:
    Oct 10, 2017
    for gods sake get an emgo tank
     
  14. blaisestation

    blaisestation

    Joined:
    Apr 10, 2008
    Also shit everywhere,and after all that they donĀ“t even taste that good.
     
    gortnipper likes this.
  15. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    Mine is a Commando Specialties tank...USA made. Were you the one that had an issue with a CS tank?
     
  16. Time Warp

    Time Warp .......back to the 70's. VIP MEMBER

    Joined:
    Dec 3, 2012
    I think your tank started off in India one way or another ?

    I can't knock the made in India stuff, I picked up an Interstate tank (6+ kg bare weight) years ago and it still looks good in bare metal, it will be on the plane to New Zealand with me tomorrow for delivery to its new keeper.... 3000kms + riding around India was fine also, maybe even a trip back this year.

    What I would like is a steel EMGO Fastback fuel tank.
     
    Last edited: May 21, 2019
  17. alan hodge

    alan hodge VIP MEMBER

    Joined:
    Oct 10, 2017
    tornado....yes it was me
     
  18. MikeG

    MikeG

    Joined:
    May 31, 2012
    I plug the filler with an expanding rubber plug, fit a pressure gauge to one petcock opening and hook an air adjusting valve with gauge off my spraygun to the other petcock hole. Hook the line from my compressor to the valve and open it to 4 or 5 psi. Shut it off and look for a drop in pressure on the other gauge. Saves leaving a ring in the bath tub.
     
  19. jbruney

    jbruney

    Joined:
    Jan 5, 2019
    Why all of the sub tactics when you can just pick up a bottle of Snoop or use water/dish soap & set it up on the bench? It'll bubble up at any leak with the 3-4# pressure pinpointing the leak/s leaving the tank dry and easy to mark. Just saying......Just squirt a bit along the seams & welds, or any suspect areas your heart desires because it bubbles for a considerable time on the leak. If there is one.
     
  20. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    Nope...Commando Specialties makes them in USA....see their announcement blurb on their site:
    https://commandospecialties.wordpress.com/2012/05/24/need-a-new-norton-commando-roadster-gas-tank/
    I did that while I had the nitrite glove inflated over the filler, but could not see any bubble points, I do suspect leakage at one/both petcock as they are junk ones with badly worn seals. But again, didn't see bubbles with soapy water. Might be the Wife all natural dish soap just doesn't make good bubbles.
     

Share This Page