Water pump blues

4 replies to this topic
  • thumpsalad

Posted April 27, 2002 - 06:59 PM


Once again, I find myself posting about water pump probs...

I ordered all new parts for the water pump on my 99 YZ400. When I installed everything per the Clymer manual, I notice the shaft doesn't spin the bearing. The bearing is seated properly in the housing, but when I turn the impeller shaft, it spins inside the bearing, but the bearing doesn't move at all...almost like it's binding. I can get it to spin a little, but I have to force it. Will it free itself when it gets warm from the motor or what?

  • MANIAC998

Posted April 27, 2002 - 11:32 PM


Good question. Next weekend, I will rip mine apart to do a clutch mod. I can tell you what I find out about my pump bearing then. I'm sure you don't want to wait that long though. So good luck!

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  • Thumpster

Posted April 28, 2002 - 05:49 AM


Same here, I'm waiting on parts to arrive. If it doesn't take too long. I'll let you know how it went.

  • thumpsalad

Posted April 28, 2002 - 07:13 AM


Hey guys, I figured it out!

When you install the smaller (it goes behind the bearing) of the two seals, MAKE SURE it is seated af far as it will go in to the housing! If it is not seated all the way, the inner bearing race will drag against it! That was the problem here! Mine was not seated and maybe off by about 1mm and that was enough to make the bearing drag.

  • Thumpster

Posted April 28, 2002 - 10:56 AM


Good to hear that you fixed the problem. I'll watch for that when assembling my bike. Thanks. :)

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