Opt, I'll check it first as well as the clearance,it run perfect until it flipped over in the water. His is exhaust is aftermarket with no restrictions,hope the valves aren't warped from the cold water

 

Well I got quite a surprise tonite! Got the front plastic off,tank ect... Pulled the rocker cover,intakes were tight so I adjusted them and rechecked the compression and no change so I started to remove stuff for a top end pull and when I unbolted the exhaust at the head I was shocked at the clay water dripping out the head! They tried to start the ATV for quite a while when they got it out the water but it never restarted once it cut off and most of the water entered through the exhaust. I saw the oil that come out the motor and it had a very slight hint of water in the oil but it was not milky, the crankcase breather hose looks clean. I'm debating on just doing a top end job or do a complete tear down? Most I've been into and split cases were no brainers,they had been run and were full of water but seems like a majority of the water and mud got on top of the piston and the cylinder got damaged from trying to start it or got distorted from the rapid themp change causing a instant loss in compression

 

Once you pull the cylinder you can tell pretty quick on condition of lower end.If there isn't water in it,possible just to go with the top end rebuild.Plus you could always drain the crank case, fill the bottom end with kerosene,roll the rod around and drain the crank case.Throw some cheap oil in the crank case,roll the rod around again and drain. If there's any small amount of dirty water in it this should flush it out.

 

Well, pulled the head and cylinder, a pure mess! A lot of mud in the case so it's time to tear it down

 

Ooops.. Engines just don't like water and mud.

 

Isn't it like when your a kid and you eat dirt and then you get exposed to stuff and then don't get sick as much as your buddies? I was always told to throw some grit into the oil tank so the motor builds a tolerance while it's still young...

Just my 2cents LOL

 

I've used mud to 'wash' my hands of grease many times but i never occurred to me it would help my engines!

 

Well got everything tore down, lucky a friend has a ultrasonic parts cleaner to wash everything up,not as much mud as I'd thought but enough to cause major damage,broke down the oil pump,cleaned and checked the clearances,so far so good. Got a gasket set ordered, cylinder and head are heading to the machinist tomorrow. If I have time I may put the case back together before the weekend. Shooting for 2 weeks tops to get him back running

 

Glad to hear that you broke the oil pump down and cleaned it as it's gonna suck up any crap that's near it since it's in the lowest part of the engine. Hope everything goes well..

 

Behind the oil pump in attached photo....The case was pretty dirty and after it was cleaned up this "shiny brass" in the oil passage area kinda stands out,I don't think anything would be there...just wanted to be sure