If you own a WR/YZ400F WR/YZ426F, WR/YZ450F or a YFZ450 Quad, then chances are you’ve experienced the problems associated with water pump leakage. The problem really isn’t the water pump, but more specifically, the water pump shaft. The surface of the water pump shaft develops “grooves” from the seals, and degrades the seals too in the process, thus creating that annoying leak that not only leaves puddles on your garage floor, but also reduces that coolant level enough to cost you an engine failure. We found the fix to be a shaft with a special coating applied to it that is harder than the surface of the factory shaft, and is also low drag at the same time, making it a win-win part all the way around!
NOTE: Will not fit the YFZ450R Quad
