Joyner JNSZ650DLB Owner's Manual And Parts Manual page 54

8) Check the spark timing. Adjust if need as followings
a) Loosen the nut of the distributor housing
b) Turn the distributor slowly. Increase the spark timing by counterclockwise turn.
Decrease the spark timing by clockwise turn.
A. Gear shift
1) Install thick pivot plate and short crank to shifter shaft
(See Figure 68
Figure 71)
Figure 67
Figure 69Figure 70