When you reassembled the engine, did you make sure the timing chain tensioner was wound up and held tight when you installed it? If you don't wind the timing chain tensioner and keep it tight while installing it, it will cause the chain to be too loose, the tensioner will not do it's job.
I recommend taking the chain tensioner off, winding it tight and reinstalling it.

 

Yes I made a little T out of sheet metal for holding it back. I turned the engine over a couple of times then rechecked the marks before putting the rocker cover back on. I didn't look at the valve seats but I did set the valve clearance after I put the cover on. I even pulled the flywheel when I changed the stator to check that the flywheel key didn't sheer off.

 

If u want to check your valves to make sure their seating you can pull the head off. With the plug installed turn the head upside down. and pour oil or water in it and it shouldn't leak at all.

 

Would I have any compression if they didn't seat? It has 120psi when cranking

 

I have this same problem with my '06 400 EX. I get it started and running while choked then when I shut the choke off it will start to die. I changed the plug. I am in the military and am getting deployed so I don't have any time to look at it. I am thinking the carb is dirty and the gas in the tank needs drained and new gas put in. It was running great one month then I didn't run it for a few weeks and then it started doing this crap. O well prob something simple like gas. Just need the time to drain the tank and put new gas in.

 

Worked on mine most of the day and got it running. I re-adjusted the valves and tweaked the carb some more, added more fresh fuel and it started. Been running it since trying to seat the rings.

 

are you 180 out?

 

the same thing is happen to me . I have fuel , timing is on ,its firing ,i have commpression 110. i tred a new piston and clynder. it sound like its out time but i keep checking and i tried to move it a round and still wont start. i realy need some help please

 

If you want to check the valves get it top dead center and get an adapter and put air psi in the cylinder and if you dont hear air escaping from the exhaust or intake the valves are good.

 

there is a pen and a spring thats under cam that sets in the head it wont start with out it. mine fell out