Motorcycle Repair/yz400f


My buddy just picked up a Yz400f for free and after inspection we noticed water in the oil and he said its getting coolant in the exhaust, would this be the water pump seal?  Its also blowing out alot of smoke from the oil overflow hose like its burning oil.  any ideas?

Ryan, You are right. Its the water pump seal allowing the water to contaminate the oil. Also you might check the brg area on the water pump shaft as it may be allowing the shaft to move around and leak. Also these models have a lot of blow by but the water may be washing the oil away from the rings.

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Gary Blake


I have built from ground up race winning motocross bikes and atvs as well as atv,s for flat track and TT racing. I am starting to take on the utv challenges now for racing. This is a new area for me so Im in a learning curve.


I have extensive experience in off road motorcycles and atv,s.I also work on street bikes and personal watercraft, Some experience was self taught and some was factory trained. I have been working in the powersports industry since the mid 70,s I hope I can help. Thanks Gary

Was a sponsor for K.O.R.R.(kansas off road riders) and now I am working with ROMEO,s (retired old motorcyclists eating out)and was in charge of the Quad Wars for the monster truck series in Central Kansas

Factory trained Kawasaki Heavy Industries. Factory trained GasGas motorcycles and atvs worked as a technician and was as a dealership owner.Kaw.Suz,Honda,Aprilia,Arctic cat,See Doo,Can Am, Bombardier,Yamaha,GasGas,Qingi,TM,Moto Guzzi,Harley,s

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