KX Riders

General => In General... => Topic started by: Motorrad on August 19, 2011, 05:36:20 PM

Title: Impeller
Post by: Motorrad on August 19, 2011, 05:36:20 PM

Stumbled across this picture on Google Img tonight... (was looking for somthing TOTALY differant).....   and Cant figure out why they are doing this.....   Ideas?

(http://i13.photobucket.com/albums/a289/Motorrad/IMPELLER_CRF450_sized.jpg)

Title: Re: Impeller
Post by: Friar-Tuck on August 19, 2011, 09:30:05 PM

When my kid got an '02 CRF 450 I started scouring the web for everything I could find on the older bikes, so I could go through it and fix/ upgrade anything I could afford to. 
        Apparently the standard type design was creating a vacuum/cavitating behind the impeller that was causing the seals to leak.
     By adding a small hole to the impeller, it not only equalized the pressure behind the impeller, it actually creates a little positive pressure, which helps maintain a much better seal.
    I put two holes in my kids '02 (opposite each other)   and never had a problem.
 
   In '06 Honda produced their part with the hole, and it will retrofit onto any prior year CRF450.
   The part number for the new item is: 19215-MEN-850. 

  Tuck\o/