teflon tape

Discussion in 'Motorized Bicycle General Discussion' started by leo, Mar 27, 2016.

  1. leo

    leo Member

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    got my second bike almost finished. it didn't come with the little red petcock washer/gasket. can i just use teflon tape on those threads for now?

    i found several articles on the internet saying that it (white teflon tape) will dissolve in gasoline if given time, and some specifically saying it is the "preferred" method of sealing the petcock valve.

    i would think it should be ok to at least use it temporarily, until i can get a real one...

    so what say you, wise old sages???
    will it really stop up anything if i use it for a week or so???

    note: yes, i know about the yellow teflon tape. but i don't have any of that kind... and it's easter sunday... lol.

    BTW... Happy Easter!
     
  2. 2door

    2door Moderator
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    Teflon tape is not a thread sealer but in fact a lubricant. It was made to be used on tapered pipe threads as opposed to using a liquid or paste pipe 'dope'.

    Yes, some people use it and swear it works but what it is actually doing is taking up some space and 'acting' like a gasket. The petcock, and tank are not tapered pipe threads but a 10mm machine thread. It needs a gasket to seal the petcock flange against the tank bung.

    A gasket can be easily made. Use a material made to be used as a gasket. Don't rely on cardboard or paper.

    Tom
     
  3. bairdco

    bairdco a guy who makes cool bikes

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    I use it all the time, but I use the gaskets, too.

    You can find the fiber washers, and copper or aluminum "crush" washers at industrial fastener stores, and some good auto parts store.

    There's also a few old timer mechanic tricks, like wrapping string into the threads to make a seal.
     
  4. crassius

    crassius Well-Known Member

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    the tape works OK to seal leaks - I also like to use an o-ring tho because it gives you more latitude in getting the lever into a convenient place
     
  5. Agreen

    Agreen Member

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    If you use an o-ring, don't use a rubber one. Rubber turns to goo in the presence of petroleum. I know this from building rotary engines. The coolant seals are rubber, and the factory service manual suggests using petroleum jelly to help install them in the seal grooves. I did that once and came back the next day to find the seals had swollen to twice their size. Same idea for fuel hose. Use "rubber" hose that is designed for fuel systems. It's either not actually rubber, or it's lined internally with something petroleum resistant.

    Teflon doesn't have a problem with fuel. I've used it in many fuel systems and never had an issue. The reason some say to not use it is because people don't properly place the tape and end up getting some in the system, which means it can get stuck in a carburetor or injector.

    Since you're in a pinch and want it back on the road, get a 10mm copper or aluminum crush washer from a parts store. Most auto parts stores have them.
     
  6. xseler

    xseler Well-Known Member

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    If you use Teflon in conjunction with a petroleum product, be sure to use the "yellow" tape. It's made for petroleum. The white will sometimes have issues.

    Good luck!
     
  7. crassius

    crassius Well-Known Member

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    99cent store near me sells packs of nitrile o-rings - works well with fuel (good for the drain screw on carbs too)
     
  8. leo

    leo Member

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    so far so good, no leaks.
    thanks for the input guys.
     

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