A buddy of mine has a 2004 WR450F. We went riding today and just a few miles into our ride he had smoke and oil leaking everywhere. I towed the bike back to our home and couldn't find anything that could be leaking. But today I noticed up on the front of the cylinder head a little round hole near the exhaust. It looks like a cap of some sort has came out of this hole. Is that normal? Any ideas?