As many of you know, I like to squeeze as much out of my engines as possible. While working on my Accucraft NGG16, I noticed that the front engine ran smoother in forward, and the rear engine ran smoother in reverse. This is because the beginning of the admission events are a little later for the rear engine in forward. To bring the best of both engines together in forward, I loosened the direction shaft u-joint on the rear engine while in reverse, and and cranked the front engine to forward and tighened the u-joint set screw. At this point I moved the eccentric crank arms to the other side of the axle shaft and adjusted the valve stroke to 4mm. On the track the engine MUCH ran smoother, although I have no neutral or reverse.