The first thing you need to do is check the timing, no you do not have to remove the recoil starter cover to do this, there is a plastic plug on the left hand side of the rocker cover you will need to take this out ( it will be kinda hard because of the adhesive) this will allow you to inspect the timing marks on the cam itself. Take the sparkplug out after you get the plug out use a screwdriver and use the pull rope to get it to top dead center. You can use the pull rope and turn it over until you feel some compression hit your finger then put the screw driver in to get it all the way up. Then once you do that get a light of some kind and look in the hole where you took the plug out to look at the cam timing marks they should look like the picture below. If the timing marks are correct and it still will not crank then you will need to adjust the valves and I can help you do that, but we need to verify the timing first. Now the little drawing is not to scale but just to give you an idea of what to look for. The black is the the cam and the red is the top of the head.
It is important that you get the engine on the compression stroke because if you do not the timing marks will be off regardless of how close they are to being correct, Just letting you know and not being a smartass.
The two black slashes are on the edge of the cam and they should be as close to parallel as possible to the top of the head this is crucial in getting it to run.
Just be careful when putting the cam gear on and not let the cam turn because if it is just one tooth off it will cause problems. It may take a couple of tries but it is worth it in the end.
When setting the valves you can use the feeler gauges like the factory says OR you can try it my way which I haven't had a problem with.
Once you get the inspection caps off, make sure that the piston is still at TDC and then use a 10mm socket to loosen the lock-nuts but just enough for you to be able to turn the set screw. After you have everything loose tighten the set screw until you feel it bottom out then(INTAKE) bottom it out then loosen it a 1/4 turn and then finger tighten the nut not allowing the set screw to turn. (EXHAUST) do the same thing except go about 3/8" turn with the set screw. The valves should be .003-.005 INT & .006-.008 EXH Let me know if you need anymore info.