This ****e happens to me too. I'll be in N at a red light, then try to put it in first, just before the light turns green and it won't go. It is such a PITA. So I ordered a shift kit from Factory Pro. I just got it in the mail and they sent me the wrong one. I called them and the guy on the phone was like.... "Well I dunno, Maybe it'll fit." I remided them that I pain over $230 for the damn kit and I would like some support. The guy said, "Just send it back and you'll get a refund."
"A refund!?" I don't want a refund, I want a transmission that will F'n shift when i want it to!!!!!!!!
I guess I'll just have to find another company that makes a shift kit.

 

shift kit, as in quick shifter?

remember that shift arm geometry can play a role, and getting into first from neutral happens on every bike, everywhere, ever made. just one of those things.