HI Hymodyne
I got this off another M/C list.
If you find yourself wanting to shift into Sixth, in a five speed, use a bigger front sprocket or smaller rear sprocket. If you find yourself wanting to down shift into fourth all the time, use a smaller front sprocket or larger rear sprocket. A larger sprocket being one with more teeth.
Honda's change from 34 to 37 was to compensate for a change in the gearing between the engine and transmission.