Impeller Removal???

4 replies to this topic
  • calvin71

Posted March 26, 2006 - 02:52 PM


Does Anyone Know How To Remove The Water Pump Impeller Of A 426 2000? When I Try To Take It Off It Just Spins Or I Should Say It Turns The Bike Over.

  • grayracer513

Posted March 26, 2006 - 04:40 PM


You should not attempt to remove the impeller from the w/pump shaft while the case is still mounted on the engine. Doing so puts all of the torque load on the drive tab of the shaft, and you will very likely break the tab off if you persist. With the case removed, you will find a set of flats on the inboard end of the shaft that you can use to hold the shaft with a wrench while unscrewing the impeller.

Note: the impeller will not come off easily, and a little heat and/or an impact wrench is useful. It is a normal, right hand thread.

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  • pjacobs433

Posted January 20, 2010 - 08:21 AM


Although this post is almost 4yrs old, I feel the need to interject a little experience after searching a thread for some answers and performing the work.
I had some coolant weeping out of the bottom of the case and was able to remove the impeller and replace the seal without incidence, or removing the casing.
YZ450FS 12mm socket on the impeller, bike in first gear and brake on, short burst of force to the ratchet and easily broke free. I wouldn't worry about breaking the tang in the balancer since the impeller is aluminum. Dental pick to the old seal made for quick removal. Lithium grease on new seal on the inside and outside started by hand and seated with a socket a few light taps of a hammer.
Don't be intimidated, make it happen.

  • grayracer513

Posted January 20, 2010 - 09:16 AM


I wouldn't worry about breaking the tang in the balancer since the impeller is aluminum.

Even though this was your experience, and in spite of the fact that you got away with this, you have given some terrifically bad advice here. If you continue to search this subject, you will find at least one case of an owner who tried this little shortcut and did in fact break the drive tang off.

Furthermore, doing the job from the outside like this makes it difficult, if not practically impossible to inspect the shaft for the groove the seal commonly will wear into it, and installing a new seal on a grooved shaft is a failed repair in progress.

Add to that the fact that one potential cause of a leak at the water pump is a worn bearing at the balancer shaft, and unless the case cover is completely removed, you can't inspect for that.

If you shortcut this repair because you're too lazy to do otherwise, you may get lucky, but the odds are against it, and you deserve what you get from it. Don't say you weren't warned. But removing the case cover and doing the job right is just not that difficult. If you're thinking of trying the shortcut because you're apprehensive about the job, "don't be intimidated, make it happen."

  • speakaman

Posted January 20, 2010 - 09:37 AM


I have a 2000 426 & had the same problem, changing seals& bearings IS NOT a hard process, it just takes a little time.. so do yourself a favor & change all pump seals & bearings & shaft @ same time. then you KNOW it's repaired. small change compaired to a complete rebuild due to a hot running engine...these engines DO RUN HOT...

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