Fuel filters

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2door

2door

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Staff member
Sep 15, 2008
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Littleton, Colorado
scotto- said:
Yes Tom, those are metric pipe threads equivalent to a US 3/8" per se. The poster asking is in Australia and they're metric down-under, so close enough to 3/8" with metric thread pitch.

As for using 3/16" on the larger barbs, just heat tubing up and add a drop of oil to it....slips right on and no need for clamps as well. You pretty much need a razor knife to remove it however.
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Scotto,
Just to clarify...yes, it might measure about 3/8" in diameter but the actual pipe size is 1/8" pipe. Screw pipe sizes are notoriously wrong. I don't know where they started but take any NPT (National Pipe Thread) pipe/thread, inside diameter or outside diameter and you will not be able to measure the size...anywhere. Go to the hardware store and ask to see a 3/8" pipe nipple/fitting. It will actually measure close to 1/2" O.D. and well over 3/8" I.D. Some will say that 1/8" pipe is 1/8" I.D...Not so, just measure it. Same for 1/4, 3/8, 1/2 and on up. I stand by my earlier post in that the kit supplied tanks/petcocks have a metric machine thread,(about 3/8" in outside diameter) not a tapered pipe thread and therefore rely on a gasket to seal.That's why they put the little red gasket in the kits, to seal the petcock against the tank fitting. Tapered pipe threads seal by tightening the tapers together. Not trying to be argumentative, sir, just stating facts.
As for getting 3/16" tubing on the barbs...heck, if you can get it on, more the better. The smaller tubing would probably look cleaner than the fat stuff. :)
Tom
 
scotto-

scotto-

Custom 4-Stroke Bike Builder
Jun 3, 2010
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Ridin' inSane Diego, CA.
2door said:
Scotto,
Just to clarify...yes, it might measure about 3/8" in diameter but the actual pipe size is 1/8" pipe. Screw pipe sizes are notoriously wrong. I don't know where they started but take any NPT (National Pipe Thread) pipe/thread, inside diameter or outside diameter and you will not be able to measure the size...anywhere. Go to the hardware store and ask to see a 3/8" pipe nipple/fitting. It will actually measure close to 1/2" O.D. and well over 3/8" I.D. Some will say that 1/8" pipe is 1/8" I.D...Not so, just measure it. Same for 1/4, 3/8, 1/2 and on up. I stand by my earlier post in that the kit supplied tanks/petcocks have a metric machine thread,(about 3/8" in outside diameter) not a tapered pipe thread and therefore rely on a gasket to seal.That's why they put the little red gasket in the kits, to seal the petcock against the tank fitting. Tapered pipe threads seal by tightening the tapers together. Not trying to be argumentative, sir, just stating facts.
As for getting 3/16" tubing on the barbs...heck, if you can get it on, more the better. The smaller tubing would probably look cleaner than the fat stuff. :)
Tom
Click to expand...
No quarrel here bro, you are 100% correct on this issue. And even though they are not pipe threads, I still use several wraps of teflon tape to help seal and get the petcock in a desired position. I used too be a plumber btw, so I understand what you are talking about.....cheers.
 
2door

2door

Moderator
Staff member
Sep 15, 2008
16,302
175
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Littleton, Colorado
scotto- said:
No quarrel here bro, you are 100% correct on this issue. And even though they are not pipe threads, I still use several wraps of teflon tape to help seal and get the petcock in a desired position. I used too be a plumber btw, so I understand what you are talking about.....cheers.
Click to expand...
We'll keep sluggin' away, Scotto and steer them in the right direction :) If only more folks understood the thread issues with their tanks and petcocks we wouldn't have so many complaints about fuel leaks. Wish us luck.
Tom
 
KCvale

KCvale

Well-Known Member
Feb 28, 2010
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Phoenix,AZ
2door said:
We'll keep sluggin' away, Scotto and steer them in the right direction :) If only more folks understood the thread issues with their tanks and petcocks we wouldn't have so many complaints about fuel leaks. Wish us luck.
Tom
Click to expand...
I agree too.
Have not had any issues with screwing on the Grubee tank petcocks with the red gas gasket and some Teflon tape other than they seldom line up pointing where i want.

Then again, I think this is yet another 'can't start and ride away on it' safety measure.
If the tank petcock s sideways or even facing back it is as least somewhat hidden.

You can see what I am talking about with that as well as fuel line with this pic.



The skinny tank petcock fitting needed screwed in past ideal for some, but great security wise.
I put the stock clear gas line on it first and cut off just after the fitting, and then just fit the larger diameter automotive gas line over it.

The other end fits tight on the carb, but as mentioned, the carb nipples can be different sizes!
Works for me, and no gas leaks.

ANY leaks to me are unacceptable, and really it is just not that hard to keep any drop of anything hitting the ground where it parked even if you don't shut off the gas flow or rode it really hard.

Again just me.
Take it or leave it.
 
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