04 yz450f coolant leak need help

Just bought this 04 yz450f and took it out yesterday and when we stopped to take a break coolant started pouring out of the little weep hole under the water impeller. Has this happened to anybody else and can someone help me with how to fix the problem?


You need water pump parts 1 ( #5GR-12458-00-00 SHAFT, IMPELLER ), 4, ( #93109-11073-00 WATER SEAL ), 5 (#93102-12106-00 OIL SEAL (SD 12-22-5 HS) )as well as the right side engine cover gasket.:applause:

This is very common issue on our bikes.

You may not need the shaft, but you need to check it. If it has a significant groove worn into it by the seal, it needs to be replaced, or it will cause the failure of the new seal.

I had the same problem with my 06 YZ 450 and I just replaced the waterpump seal. Not the oil one just the water side. I haven't had any problems since, but there was only like 5 hours on the bike when it happened. So it would be hard for the shaft to be worn by then.:applause:

Check your vent hose before taking it apart. Mine was clogged and it started leaking when hot. After clearing it, problem went away. I still get some wet marks after motos but no noticible loss of fluid. I went ahead and got the seal,shaft and gasket, but haven't needed them yet.

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