When I recently had head work done, the valves that were installed were 2 piece(valve head welded to stem)now, I had no idea until a fellow Bastard dropped the dime on me. I would never had known cuz' I had never heard of 2 piece valves. These are the ones you can get all day long on ebay and some will have Harley part #'s cast on to the valve face. Complete shit. I went and got some NOS factory stainless valves for my build. Big difference in quality just from the naked eye. Anyway, Tyler(Lowbrow Customs) rode his pan down for the Round up...and on his way home it dropped a valve(turns out it was a 2piece)...Of course the valve could have gotten hung up in the guide to start with, but it sure looks like the weakness of the welded valve was a major part of this problem. So I just wanted to put it out there that this shit happens, and hopefully it will help someone avoid this fate.