NU50 Crank Seal Replacement

NU50 Crankshaft oil seals replacement

Seal size

Flywheel Side - '15x25.5x7' Same as PA50 Oil Seals

Variator Side - '20x31x7'

Flywheel Oil Seal Replacement

The PA50 Stator plate pushes this seal into the correct orientation but the stator is built into the cover on the NU50 so you will need to drive the seal into the correct position yourself. The NU50 right case half is not tapped for a screw on stator.

Variator side crank seal replacement

  • Remove the side cover for the variator including kickstart lever
  • Use a piston stop and remove variator nut
  • Slide off components off of crankshaft until the gear is left
  • Use great caution when using a 3 jaw puller to remove the gear. If you are not careful you may split the end of your crankshaft threads. Use a nut that will protect the threads of the crankshaft or an oversized nut as pictured to move the pressure from the 3 jaw puller to the crank taper where it will not inflict serious damage.

Urbanexpressseals1.jpg Urbanexpressseals2.jpg

  • remove seal with favorite seal pulling method
  • Sanatize area of oils and sand (Emory cloth) any groove defects in crankshaft or seal area in case so the new seal doesn't fail prematurely. drive in seal flush with outer race
  • reassemble the gear you pulled off and the variator. Use your piston stop the other way to torque the variator nut.
  • Install other kickstarter gears with the correct orientation
  • Install cover and kick lever