A friend picked up a rebuilt Skidoo crank for his 99Formula 500 deluxe that I am rebuilding for him part#421000151 and this crank has a labyrinth bushing between the bearings on the pto side and his old one did not. Does anyone know if this crank is a drop in or do I have to do anything to the outer bearing. The dealer where he bought it said it fit 96-2000. He also tried to sell him some isoflex grease.If this bearing gets lubed by the injection oil would packing the outer bearing hurt anything? According to the skidoo web site the crank for a 2000 -500 has the labyrinth bushing and the engine cases for both years are the same. I guess I am concerned because the cranks do not look alike and wonder if the bushing thing affects the lubrication of the outer bearing. Any help will be appreciated. I could not find that crank part # on the Skidoo web site, maybe because it is a rebuilt unit.