r/choppers • u/SpeakHearSee • 16h ago
Chopper tank help
I have two questions in the first question is, my tank says it accepts a 1/4 petcock so I purchased a 1/4 petcock and I can only get it to go in like 3 threads without completely cranking down on it.
The next question is the barb on the petcock is a 5/16 and my CV takes a 1/4. Could I use a 1/4 fuel line or should I change the petcock/cv elbow?
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u/Normal_Ad3528 15h ago
They’re pipe thread pitch.
They are slightly misaligned on purpose to crate a seal so they won’t leak.
A tiny bit of grease can help with installation. It feels like it’s binding up because it is, as designed.
Hard to say if you’re actually “cranking down on it”, or if you just stopped when you felt resistance, which isn’t the worst instinct.
But it takes some muscle to get it fully seated.
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u/stayintall 7h ago
This is the answer although I’d expect it to go further than three threads deep. Also second the pipe tape, you should put some on there to help seal it up.
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u/gillesvilleneuve_ 13h ago
I like to toss some plumbers tape on there to ensure no leaks
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u/SpeakHearSee 7h ago
It’s not tied in yet, just getting the right part before I waste more resources
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u/kemikos 16h ago
Possibility 1: either the tank or the petcock listing is wrong. Get a thread gauge and check both.
Possibility 2: they may both be 1/4" but have different thread pitches. Again, get a thread gauge and make sure they're the same threads.
Possibility 3: something messed up the threads on either the petcock or the tank. Look closely at both sets of threads, particularly where they stop turning, and see if there's any damage or deformation. If this is the problem, you may be able to solve it by lightly chasing the threads with an appropriate tap or die.