2013 honda rancher 420fm
I picked this up cheap as a "only needs rings" deal knowing more was wrong.

I replaced the spark plug, piston, rings, cylinder, pin and clips, intake/exhaust valves, stem seals, inner/outer springs, cotters and all new gaskets for the top end.
I adjusted valves and timing mark lines up with TDC piston so the timing should be good (if i understand).
Compression is 115psi, I have strong spark and the injector is spraying gas.
Below is a video of attempted startup. Hopefully someone can give some advice before I give up and take it to the dealer

 

Firstly did you set the valves at TDC on the compression stroke? If you did, someone may still have set the cam timing wrongly, difficult to tell, unless you remove the clutch housing and check if the TDC mark lines up with the one on the cam sprocket. However, it could be that the injection system isn't firing enough fuel, either because of a blockage, or pump not producing enough pressure, I sometimes squirt a little fuel down the intake, if you then get the engine firing, it is a fuel problem.