Just wanted to take a minute and share a oil pump failure experience I had on my 98 Wr400. I picked up the bike in non running condition and it turned out to have a roasted head. I rebuilt the top end and was having a head oiling issue and it turned that one of the steel ball bearings dislodged from the pump only allowing the oil to flow back into the crankcase and not through the filter and up into the head. I assume this caused the original failure and I ended pressing the ball back in and it's working fine. Should I worry about it dislodging again? It's kinda got me scared and I was wondering if anyone has experienced a similar situation. I assume it would take some serious pressure to initially force the ball out in the first place and I'm now wondering why the heck they would use a couple balls to seal the ends anyway. Any thoughts?