just bought the bike. changed the starter. Bike ran fine for a short time. All at once a knocking sound started in the lower crank area near the front. we stood the bike up to change the starter and did not know the case oil would run into the air box. However when i checked the oil it was white ( water in the oil ) assuming there was still oil in the case, The problem im having is the knock sound. Bike runs strong so im thinking not the top end. it is most noticeable at idle speed. it corresponds with the rpm of the motor. some help would be great before i tear into it. Im thinking counter balance bearing is bad along with water pump seal?

 

sounds to me like you are thinking in the right area, the only 2 things that would cause milky oil in the counterbalance is the water pump housing/seal leaking, or if somebody dipped it in a stream. It looks like you are going to be pulling the flywheel.

 

ya. Im hoping its just the bearing causing the knock. If so i found a kit with all the bearings and seal for that area of the motor. $110.00 ill need a flywheel puller but have many friends with that stuff. Do you know if the residual combustion oil lubricates the crank shaft bearings or do they share the counter balance oil hosing ?

 

Counter balancer oil just lubes the balancer gear, crank gear,bearings and oil pump gear. 75cc of oil doesn't go a long way on doing this! Sooner you can catch a water pump leak on a 400 the better to keep the coolant from doing damage. The engine is lubricated by the oil pump and remote tank and doesn't share counter balancer oil. Be sure to check the rod bearing out for any up and down play (NO play allowed) side to side play ok. Also worn piston slapping can sound like a bearing going out also. OPT

 

Thanks I will check it out. hoping its not the connecting rod bearing. i will be starting the job around Christmas. hope to have her running again buy late January. By the way there appears to be a drain plug in the crank case. should this be drained of fluid regularly?

 

10 mm drain plug under counter balancer area. Manual says drain and fill every 100 hrs,but I would change it every 50 hrs. Same as I would do for the hub fluid. Lot of motion in these areas with very little fluid! 30 wt or 10w-30 synthetic motor oil in the counter balancer, Demand Drive Plus hub fluid in the hubs.Transmission can usually go yearly(depends on use) Polaris AGL fluid. OPT