yz400 99 model

Hi i have traded for a yz400 it has new valves rings and the works .i did not know the way to start this until i looked it up.it was different that most bikes.but it would not start probly because we flooded it.so we pulled it with a 4 wheeler and finly got it started but it quit running when i pushed the red knob in and we tryed pulling it again and it was like it was locked up and it would just drag the rear tire.and when i went to kick start it again the kicker would not move so i rolled it back and forth in gear and the kicker would kick just a few inches.could it be vapore locked.thanks for any help

thank you sounds like a valve broke or timming chain maybe.i will take it a part.it was kicking until after i pulled it and got it started and pushed in the red knob on the motor and killed it.wich is the lean.but its probly a colapased valve and they were put in new not long ago in sept and was rode 1 time and after that it set.until now.but thank you very much and have a great day