From an engineering standpoint, it is difficult to design a machine or mechanism that achieves multiple objectives with minimal compromise. An amphibious car is a good example. A few have been manufactured over the years, and they achieved the goal of navigating on land and water, but did neither very well. On the other hand, a Swiss Army knife achieves multiple objectives with minimal compromise. You can snatch the cork out of a wine bottle or kill somebody all with the same widget. The DD6, or Direct Drive 6-speed, combines 3 technical approaches to achieve the most advanced transmission gearset design available for your Big Twin with minimal compromise. First, 1st through 3rd gears are straight cut (spur) for strength during maximum acceleration with no parasitic axial thrust. Secondly, 4th and 5th gears are automotive style helical gears for quiet and smooth operation as highway speed approaches. Lastly, 6th gear is direct drive which means there is no underdrive or overdrive in top gear which translates into 99% efficiency for minimum parasitic loss, minimum wear and tear, and maximum fuel efficiency.
But we didn't focus solely on the gearset, we made this sucker shift like glass. The sequential motion of the hard chrome plated forks is controlled by a fixed spindle radial ball bearing mounted shift drum. Hard chrome guarantees long fork life with minimal imposed friction on the fork groove of the gear. The fixed spindle drum design eliminates any chance of binding or imposed friction about the axis of drum rotation. Drum rotation is controlled by a roller detent and actuated by a BAKER shift pawl with a anti-overshift feature. To make finding neutral an easy chore, we mounted a redundant detent on the left side pillow block.