1971-1973 Arctic Cat Snowmobiles Factory Service Manual, Page 51Get this manual
ENGINE SERVICING (TVVIN CYLINDER) C)
Slowly rotate the flywheel clockwise until the continuity light brightensWhen the continuity light brightens, it indicates the firing moment of the engineNOTE: The "F" mark and the timing mark in the crankcase should now be in alignmentDIAL INDICATOR METHOD 11To check the timing using the dial indicator method, use the following procedure: A) B) Perform steps8Rotate the crankshaft to position the piston at Top Dead Center (TDC)Install the dial indicator adaptor into the spark plug holePlace the dial indicator into -the adaptorNOTE: DO NOT LOCK INDICATOR INTO POSITION
If the timing marks are not aligned, loosen the two (2) stator plate retaining screwsIf the "F" mark is positioned to the right of the crankcase timing mark, rotate the stator plate counterclockwise to advance the timingIf the "F" mark is positioned to the left of the timing mark in the crankcase, rotate the stator plate clockwise to retard the timingNOTE: The "F" mark and the timing mark in the crankcase should now be in alignment