If its not shifting you might want to look in the tranny through the whole on the left side which the whole is covered by the black rubber plug. Look inside and all you need to do is turn spur gear clockwise to locate the adjustment hole. Once you've found the hole, turn one of the wheels to turn the second gear clutch so you can find the adjustment screw. You will notice two screws but the adjustment screw for the shift point is the second screw. Turn it clockwise for a later shift, turn it counter clockwise for an earlier shift. Sounds like you need to turn it counter clockwise for an earlier shift. Don't mess with the first screw.