I am trying to resist the urge to say "Right, change the motor out or pull the heads off before you check the WP". WP rebuilds are a well known maintenance item--and 45k miles would be a near record without a pump rebuild. Are you sure the bike is not overheating? You said bike was overheating on your 800 mile ride day. Checked for signs of water in the oil?
KTMs--300, 518, 990