New Gas tank on Cranbrook issue...with pics

Discussion in 'Frame Mounted Engines' started by cmos303, Jul 21, 2012.

  1. cmos303

    cmos303 New Member

    I'm doing my second build, another cranbrook, this one with a 66cc skyhawk, my first was a 49cc skyhawk on a cranbrook.
    The first kit (49cc) has a mfg date of 7/20/2011. ordered a couple 66cc kits, mfg date on those is 4/30/2012. Very recent built kits. Heres the problem.
    The newer kits have a gas tank with a threaded nipple that points straight down, not angled outward. This will directly interfere with one of the two 'side' tubes. the treads on the nipple / bung and petcock are M10x1.0. A 1/8" Male Iron Pipe (MIP) is VERY similar.

    One huge difference is the pipe threads are supposed to seal because of the taper, where as the Metric seals against the seat/gasket.
    I've used a pair of Brass 1/8" MIPx1/8" FIP street elbows to offset it a little, as can be seen in the pic. (Watts A-712, at home depot, $2.87 ea) DSC00160.jpg
    I used tons of 'Seal All' sealant/adhesive on the threads, and tightened it all down pretty good.

    The only M10x1.0 elbow i could find was on Jegs site (auto parts) and was like $12ish plus shipping.each.

    Was this a good solution? should i have 'brazed' it (which i have no idea how to do)? do ya'll think this thing will eventually leak? DSC00159.jpg

  2. tooljunkie

    tooljunkie Member

    i still dont think fittings are metric,possibly british straight pipe?
    its so close to npt i really dont know what to say.
    with the sealant,if allowed to cure properly should be fine.
    i havent tried my fuel valve on my custom tank yet,still have to clean up my welds and add a front mount and vent line.
  3. Go to the auto parts store or u pull junk yard and get M-10x3/16 soft brake line with flared end fittings. Most older foreign cars used this size. If you have a cheap flare kit or can borrow one from advance, o'reilly's or autozone. Then you can get a small steel or brass close nipple to connect the brake line to the tank and mount the petcock (if you choose to use it) where ever you choose . The line should last forever . Below is a sample of what you could use.
  4. motorpsycho

    motorpsycho Active Member

    geeeze.....just go to the hardware store and get yourself a brass, straight barbed hose fitting. (take the tank with you to get the right thread size.) brass fittings will screw right into the tank.
    then, run the hose out of the barbed fitting so it can bend around the frame tube, and then put an in line shut off valve after the frame tube.
    you can get a plastic in line shut off valve for a lawnmower for about $5.00 at menards, lowes or just about any hardware store.
    it's a simple solution and the kit supplied petcock WILL start leaking eventually.....they are a very poor design.
    don't worry about the shut off being close to the tank. let the fuel line work its way around the frame tube, and then install the shut off valve after you've cleared the frame tube.
    rubber fuel line is a lot more flexible than brass fittings :)
    keep it simple, there's no need to make it all elaborate with steel lines, flared tubing and all that.
  5. AlexNave

    AlexNave New Member


    Attached Files:

  6. tekstep01

    tekstep01 Member

    two words home depot
  7. Jonj57

    Jonj57 Member

    Im a little late to this, but the shut off valve doesn't need to be 90* perpendicular to the fuel line to close off the gas, Mine only goes around 40-45 degrees and I've tested it for leaks and it still works perfect. Just a heads up to cranbrook frame owners