Topic: Attention those needing a 20mm 1.5 petcock - Ive a solution for you!

[ncstatecamp]

Finally fed up with looking for a proper petcock (after not really being able to figure out which size it was) I brought my primed tank into a bunch of stores (lowes, Ferguson's, multiple hardware stores)  trying to figure what exact thread I had. Turns out with my measurements the tank fit 3 things, 3/4" 18tpi, 20mm 1.5mm, surprisingly enough 5/8" od compression cap (img1), or a (and most importantly!) 3/8 Fe Compression Coupling. These last 2 were perfect fits (WTF is NPT compression thread doing fitting 41 yr old japanese tanks!?!).

So now use a 3/8" Fe compression Coupling to 1/4" compression (img2) with an interior 1/4-in x 1/4-in Copper Slip Coupling Fitting (img3) inside your 1/4" line. I made the mistake of not using the interior copper fitting the first time and had some leakage. Also make sure to use some telfon tape for some extra assurance.

Next you'll need an inline switch (img4) and, if you care to use it, an inline filter (img 5). Before all of this I was using clear 1/4" ID vinyl tubing and it fit all my parts perfectly without hose fittings. Past the inline filter I used wind shield washer hose (7/32" or 5.6mm)(img , its essentially vacuum line and the closest I could find to original line without using hose clamps.

This http://imgur.com/AgUSuZo picture is of the complete set up. I hope this helps anyone in need of a petcock alternative.

[dohcdelsol93]

good find on the fitting.

FWIW those plastic on/off switches are not that great.  They like to leak by in the off position after some age.  They make metal ones you can buy at your local lawn equipment repair shop that work much better.  You can also probably buy them at local autoparts stores.  You can also find them on ebay and amazon.

as for the hose, Tygon makes an ethanol "proof" yellowinsh clear hose that will fit our carbs (about 8mm) and will stretch to fit the standard stuff(3/8) like more common lawn mower fuel filters/shut off valves and what not.  This can also be found at your local lawn equipment.  I've seen the black stuff on customers equipment from time to time, it seems to hold up well but gets really stiff.  Which is ok but when you have to remove the tank and remove lines it will probably be a PITA and don't plan on it resealing well on your filter/pitcock/carb afer removal when it hardens. They tygon will stay flexable even after a year or two being exposed to ethanol fuels. 

there should be a sticky on where to find cheap local parts for these bikes!!!

[ncstatecamp]

Town and country (used to be known as ace hardware) has been an amazing find for small random hardware.

[dusterdude]

Be careful using vacuum hose,its not rated to use fuels

[alacrity]

vacuum hose will not last with fuel in it. It will harden, crack and worst... in high temp situations, it can "sweat" gas. There can be fumes emitted right through the walls of it - so says my materials science/chem engineer buddy.  You can find 7/32 fuel line. You can find 5mm fuel line at any place that sells vintage vw parts and it's nice braided stuff (I just bought some for $2/foot). You can find 5.5mm fuel line if you look hard enough. All these things are purpose-designed/engineered and built. Vacuum hose or window washer hose is for those applications.  Just because it's a flexible black tube apparently made of rubber just like the black apparently rubber flexible fuel lines doesn't mean it's gonna be a smart choice.

IMHO this applies to pretty much everything:

Would you use a deflated balloon from a kid's birthday party as a condom because it's cheaper than an actual condom? 

Would you drink piss instead of beer because it's a similar color and it's also a liquid?

Would you put on any pair of glasses you found at a thrift store and expect them to correct your vision instead of custom prescription-correct ones made for you?

These are ludicrous examples of course -- only Bear Grylls would drink piss given the choice.  The point is these things matter ... and when it comes to GASOLINE and it's flammability and volatility, these things matter a LOT.

stay safe out there.
:-)

[ncstatecamp]

Alacrity, thanks for the info. I was just lookin for something local without the need for hose clamps. Guess I'll keep looking.

And you say any place that sells vintage vw like its a common thing...

[bjbuchanan]

I think he mentioned the vw thing because although not local, is a pretty damn big community in general. It isn't as scarce and therefore doesn't cost retarded prices for just fuel line