05 yz 450 coolant leak

[got5steelman]

I have coolant dribbling from the water pump side of the engine, most likley water pump seal, OK next question, is it possible for the impeller to be rubbing on the water pump cover housing, during a race this past weekend I started hearing a weird noise like something in the engine was rubbing or hitting a case cover, I thought maybe the clutch cover, it seemed to be coming from the right side of the engine, after the race I noticed coolant dribbling from the right side bottom of the engine however it stopped leaking after the cooloing system pressure was gone (cooled down), I have yet to tear down and investigate, going to look at clutch and water pump. How hard is replacing water pump seals and bearings and do I need to split the cases to do this? What parts usually wear and do you need any special tools for water pump tear down? Any other suggestions on what the noise might be.

[cbrewer450]

It's really quite easy to replace the impeller shaft, bearing and seals. You need to take the pump cover off then pull off the clutch and engine cover so you can get to the shaft and seals. I had a local shop do the actual swap of shaft, bearing, and seals. They had the proper tools and I felt safer that way. Other than that, it only took a couple of hours of my time. No more leaking for me.