2004 Skidoo ZX Series Service Manual, Page 431Get this manual
Section 08 TRANSMISSION Subsection 07 (GEARBOX)
If upper sprocket is too far in, possible cause is that countershaft: bearing on driven pulley side may be too far inTo check, pull out bearing then recheck sprocket alignmentReposition bearingBearing housing (triangle) must be against frame without preloadMake sure to install hardened washer on each end of spring
Install chain no28, 44-tooth sprocket no34 and its spacer no38Spacer's large outer diameter must be against sprocketInsert coupling shaft no33 in 44-tooth sprocketInstall needle bearing no15 (wider one) in reverse gear no18Install reverse axle no20 (assembly) making sure to properly position spring pin in housing slotInstall alignment rod no19, reverse gear no18 and spacer no24Drive sprocket hole and driven gear hole must be aligned to insert alignment rodMount chain tensioner (assembly) to adjustment screw already fixed to gearboxAssemble fork no17 to axle using spring pins no16Apply grease on O-rings
Join cover (assembly) to housingMake sure fork tabs are behind sliding sprocket thrust washer1 1