The 400ex comes with a continuous chain.. No master link. I also wasted 30 min. looking for a master link before I called Honda to ask what the joke was.. If you are replacing it, just cut it with a saws-all or a hack saw. FYI the Raptor also comes with a continuous chain..

 

Don't actually cut it in half grind one of the pins off and ge a clamp and push it thru.