Maybe simpler way. Please, free to all.
SOHC 1976 - 1982 XS360 2D, XS400 D,E,2E,F,2F,G,SG. Full 266p. Yamaha Service Manual.
http://pl.scribd.com/doc/146396554/Yamaha-XS-400-H-SH-Service-Manual-ENG-XS360-2D-XS400-D-E-2E-F-2F-G-SG-Supplement-ENG-by-Mosue