how to stop gas leak

V

videomandw

New Member
hello,

i recently built a 2 cycle kit bike. i have a very slight gas leak where the fuel shutoff screws into the bottom of the 2 liter gas tank. someone on this forum said teflon tape is not a good solution. can anyone recommend a specific brand of "goop" i can put over the threads that would provide a permanent gas-proof seal?

oh, one other related question: how do i know which way the plastic see-thru fuel filter goes on? i'm not sure if mine is upside down or not.

thank you,
david welch
valparaiso, in
 
I am also interested in this. I have a tiny leak and just bought some teflon tape. I also have a tiny tiny leak in the carb drain screw, what should I use to seal this?
 
Welcome to the place vid, I've seen the "don't use teflon tape" too - but being stubborn I tried it anyway & it's worked well so give it a shot if you have some. If it ends up failing over time (mine hasn't, but who knows eh?) it'd be easy 'nuff to use some Seal-All on the threads *shrug*

There outa be a lil arrow on yer filter, the arrow is direction of flow - not "this side up" as is a common mistake. If you've no arrow - then the pointy end goes up (like a witch's hat), this way the sediment is trapped on the outside of the filtering element & you can see how dirty it's getting. If installed backwards/upside down, just leave it until ya get a new one as it'll work jus' fine... but ya just can't see the gunk building up inside it & won't know if it's clogged/dirty w/o testing as it'll always look new. If ya flip a used one, it'll puke alla nasty into yer carb ;)
 
Where can one find this Seal all? Do automotive stores carry it or a wally world product? I didn't see it at the pepboys here, just the RTV.
 
SealAll is available at most auto parts stores. Napa carries it, so does O Rileys, Auto Zone and Car Quest. I've never looked for it at Wally's place. It is specially formulated to be gasoline resistant unlike many silicone based sealants which will dissolve in gas over time. It looks and smells like old Ambroid model airplane glue but the stuff works.
As for the leaking petcock problem: Make sure you have installed the little red fiber washer on the petcock before screwing it into the tank. That is the seal, or gasket that must be there to keep the petcock from leaking. It is not uncommon for that gasket to be missing from a kit or not knowing what it is, the builder will toss it. Every one I've seen is red, about the diameter of a dime.
Tom
 
I used the red gasket deal but the problem I have is I purchased the better petcock from SBP and I can't thread it all the way into my tank. It will stop with about about an 1/8 of an inch of threads still out so the gasket is pointless. I feel like if I try to force the petcock on further with a wrench something is going to break.
 
Yellow Teflon tape works well. Almost all home supply and hardware stores carry it.

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thank you guys for the quick reply to my gas leak question. your answers should be very helpful. WHAT A GREAT FORUM; SO KNOWLEDGABLE AND SUCH A FAST RESPONSE. BEST FORUM I'VE EVER BEEN ON. THANX AGAIN.
DAVID WELCH
VIDEOMANDW
 
I could be wrong here and maybe Pablo (SBP) will step up and comment but I believe the valve they sell is a 1/8" pipe thread. The fuel tanks in most kits are a metric machine thread. To get SBP's valve to seal properly you might need to run a 1/8" pipe tap through the threads. Don't go too deep, just enough to get the valve threaded in. Pipe threads are tapered where machine threads are not. The taper is how pipe threads seal. Machine threaded fittings require a gasket.
As was stated above, teflon tape might help but it is generally not considered a sealer but more of a thread lubricant that allows you to tighten the fitting more. Some tapes have a sealer coating that is supposed to help but the thin white stuff found in the plumbing section of hardware stores isn't the greatest to use for your problem.
Tom
 
The yellow tape is about 4x thicker then the white.

If you're looking for the tap it's listed as NPT, National Pipe Thread and I my be wrong but I think it's 3/8" not 1/8".
If you run a pipe thread tap just go in as far as the threads are on the tap no further, that'll get you the correct taper.
 
This is the one I bought. It says in the description it threads directly into the tank. It does thread in just fine but about 3/4 of the way in it will get hard and then feel like it bottoms out.

Sick Bike Parts
 
SBP is a good and reputable company. I'm sure if you emailed them they would offer some advice. I've installed several aftermarket petcocks with NPT, National Pipe Threads and they all worked perfectly after cleaning up the threads in the tank with a tap. Sick might tell you the same thing or offer another suggestion. Their add and contact info can be found on the right side of this page.
Tom
 
You can use small nylon wire ties, sometimes called tie wraps, to tighten the fuel line connnections to the barb fittings on the tank and carburetor. You can also wrap those areas with small diameter wire, twisted and tightened. Hobby shops and some hardware stores sell small, 1/4" spring type hose clamps. I like the tie wraps. They're cheap and easily replaceable and available in colors. The kit supplied fuel line will harden over time and can crack. I like to replace it with fuel line made for small engines. Look for either 1/4or 3/16" inside diameter (ID) tubing at lawnmower shops or hardware stores.
Tom
 
Kevlarr said:
The yellow tape is about 4x thicker then the white.

If you're looking for the tap it's listed as NPT, National Pipe Thread and I my be wrong but I think it's 3/8" not 1/8".
If you run a pipe thread tap just go in as far as the threads are on the tap no further, that'll get you the correct taper.
Click to expand...
Kev,
1/8" pipe taps are the size to look for. 3/8" is way too big. Take it from a guy with 30 plus years in the pipefitting trade. :)
Tom
 
Hard to see but I twist mechanics wire on my fuel lines if need be.
 

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2door said:
Kev,
1/8" pipe taps are the size to look for. 3/8" is way too big. Take it from a guy with 30 plus years in the pipefitting trade. :)
Tom
Click to expand...

The correct tap size to clean out the threads in the gas tank nipple is a 3/8"-24
Take it from a guy that knows :)

And if it was a NPT thread, as stated above, 1/8" would be correct.
 
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