It could be your automatic decompression lever it's attached to your cam under the valve cover. The spring looses tension and needs to be tightened or replaced. When you flick the decompression lever it should have tension and flick back into place. If it's bad it will have nothing but play.
I think it is your valves becasue mine would run fine and then ticking started then as time went on it got harder to start until it did what you are doing but you should adjust your valves and if that’s not it take the head off and take out a couple of valves and see if the valve seat is bad becasue it wears through the seat and won’t get good compression
Did you find out what it was. Same problem. Changed piston, timing chain, tensioner, air filter, all new jets choke plug, oil change and solonoid and still no start. Does what yours does.
Take your carburetor off and double check everything, make sure everything is tight and you have no leaks from the carburetor and make sure your throttle cable is not too tight
dis you get it to start i got an ltz 400 with the same problem changed the starter clutch, adjust the timing new stator new battery new carb and still no luck
I did everything checked spark. Re-did my timming put starting fluid new carb not going to rebuild cost alot of money these kfx/Ltz are plaqued with problems worse quads!