I know you said it has new reeds, but the only time I've had that difficulty it was a (slightly) warped reed.
FWIW, I've found some bikes really like to be laid on their side before cold starting. Get that fuel really running out the overflow tubes for 5 seconds or so before picking the bike up. Kick over slow a few times to prime it, then find TDC and kick hard (choke on, no throttle or maybe just a tiny hint of throttle). If that does not work, I'm at a loss.