Okay... I'm prone to worry, so maybe this is a non-issue. I still gotta check it out.

My DRZ 400S goes into some sort of funky resonance at higher RPMs. Stock exhaust, Vibration is RPM dependent (same rev spot no matter what speed/gear I'm in).

I hear a weird noise that makes me wonder, especially when the bike is hot. Does it when cold too, but not as loud.

I slowly rev the engine, and then (i'm guessing) around 5k RPMS the engine tone changes drastically at a specific point. Sort of a BrrrrrrRRRRRRRRRRAAAAAA! and the bike starts to vibrate more. No loss of power, just a weird tone and vibration. Not a lot of vibration, but just a bit more. Bike still has an amazing amount of power across the band, even when this noise occurs. Exhaust seems tight. I see no evidence of head leaking anywhere, but have not had the tank off to fully check.

I seem to recall that earlier, I would hear this note, and it would go away if I increased the RPMs. This is no longer the case. It only goes away if I decrease the RPMs below the threshold.

HELP
Does anyone know the tech email at Suzuki USA?