This past weekend a friend of mine (names withheld to protect the allready embarrased) dumped his BRAND NEW WR450 in a creek. First day after break in and he decided to ride across this little creek instead of taking the old falling down bridge and about 3 feet into the crossing he encountered a huge hole and the back end went down to the fender and the engine died. We got the bike to dry ground and pulled the airbox lid and at least a cup of water poured out. NOT GOOD. We held the bike upright on the rear wheel and let the exhaust drain then rolled it backwards while in gear to see if any water would "backflush" thru the carb and some water did come out this way. Pulled the plug and kicked it thru a few times and nothing but fuel vapor out of plug holes. That was a small relief. Luckily we werent too far from the truck and he had a new quart of Yamalube so we drained some fairly milky oil out and put the new oil in and she started right up and wouldnt idle until the water cleared the carb. Back to the truck we went (approx 2 miles). My question is what dou you guys recommend for the next step? So far he drained the oil and completely filled the crankcase and let it sit overnight. Should he flush the engine with something or just do several oil changes and see how it runs? I am sure someone out there has done this before.