For those out there who start having long crank issues, I will confirm that valve adjustment is very important.  One of my CFmoto 400S began having starting issues, a quick check of the valves, i found that they were too tight.  After adjusting to within specs, it fires right up.

Previously as you would crank the engine, if you feathered the throttle it would fire, run rough for a few seconds, usually having to rev it a few times until it would idle.  After valve adjustment, no need to touch the throttle and it idles much better.