I tore apart my 400ex to replace the valves because the guy i got it from didn't do the timing right. So i got two more sets of valves on and set the timing right by turning it counter clockwise then it wouldn't start so i took it back apart then saw that the two intake vales were sticking out then i looked at timing chain and found out that the tensioner was all the way out. So i replace the valves turned it counterclockwise to the mark put all lobes down and tried again and didn't work. I took the rocker head off and spun flywheel counterclockwise to the t mark and lobes were up.

I think that the timing chain is stretched. I want to know what you guys think.