I don't think it's the biting. I've been working diligently on my embouchure to get that lower lip and jaw relaxed.Sounds like extreme biting to me, assuming the neck is on right, and nothing is leaking or bent.
Both scenerios are very common!
I took the mouthpiece off the neck and did an unofficial leak test. Then I cleaned the pip with a pipe cleaner. When I got the neck back on the horn I saw that the "octave key "pusher; was too far over and not allowing the octave key to close.I'd first look to see if the octave key on the neck is seating against the pip. It's common for some to bend the octave key when assembling the horn.
Excellent. Not only did you diagnose the problem, you learned how to prevent it in the future.When I got the neck back on the horn I saw that the "octave key "pusher; was too far over and not allowing the octave key to close.
Then I remembered I'd been putting my neck on a slightly different way, grabbing around the octave key arm. I won't do that any. more.
I think I'm all fixed up. Thanks guys!
Yesss!Excellent. Not only did you diagnose the problem, you learned how to prevent it in the future.
Play on!