Post a video. Probably normal.

i agree with Vic, it's probably normal and if you have any inkling that it might have been there before, it probably was.

The Gen1s sometimes had a rattle at that rpm in the Tip over sensor under the windscreen. I think Kaw tightened that up but all we did was put a couple washers under the bolts or grind the bushing down a touch.

Like everyone says probably normal. My 2007 and 2012 ZX14 ticked and tapped and clattered and they both still started everytime and ran fine. My BMW now ticks and clatters and taps. I chalk it up to normal. Inline 4's all do it!

These engines are rather on the ticky/noisy side (in my limited experience).

A rattle could possibly be getting into bodywork or IPC rattling around. 4k is right around the buzziest point on my bike and if shit's gonna make noise it's then. Bodywork rattles can be be sussed and remedied. Good God if I had to put up with horrendous rattle the little cover under the screen was making forever I would've went crazy.