11.FINAL REDUCTION/ TRANSMISSION SYSTEM MXU 500 IRS Primary Drive Shaft Countershaft Assembly Apply clean engine oil to the countershaft assembly, driveshaft assembly and primary drive shaft. Install the primary drive shaft. Install the countershaft and drive shaft assemblies as a set into the left crankcase. Drive shaft Assembly Apply clean engine oil to the shift cam, then install the shift cam. Shift Cam Lower Shift Fork Upper Shift Fork Apply clean engine oil to the gearshift fork, sliding surface and gearshift fork pawl. Install the lower gearshift fork into the clutch dog (countershaft) and shift cam grooves with its "LDB5" mark facing down. Install the upper gearshift fork into the clutch dog (countershaft) and shift cam grooves with its "LDB5" mark facing up. 11-23