400ex valve problem

[buildinitnow]

Looking for a 400ex head with valves. Anybody got one that they want to get rid of? I need one because my 440 just at a valve. The top of the piston has a hole the size of a half dollar from a valve. I had like 4-5 hours on the new motor to. When i took it apart there were two valves out. The one fell out when i took off the head, and the other was on top of the piston. Does anyone know why my two valves(opposite each other, one was intake and one was exhaust) fell out Just wondering? The other two were still in the head. Any ideas would be great and any heads for sale would be great two. All the springs were tight that hold them in to. I was in 4th gear going down a hill when it happened. Don't know much about a 400ex top end when things go wrong at this point, so anything will help. thanks

[plkmonster2]

Most likely the little drop-in clip things came out, or were broken. Are they still in the head? And, are the tops of the valves damaged?(the part were the clip hooks) Maybe the valves floated so bad that they could have fallen out?

[dork]

were you using the engine to slow you down; was it revving very high with the throttle closed? mechanical overrev like that is hard on a motor and it can increase you chances of dropping a valve.