Hi chads got your email


The grub screw is located within the small gear. If you hold the small gear and rotate the large gear you will see the grub screw clearly turn inside the small gear. this grub screw holds a spring down which in turn holds down the gear change arm, if you tighten the screw it becomes harder for the spring to release the arm (therefore holding the gear change) much the same as the clutch works. clear as mud!! basically you need to tighten this screw to hold the gear longer. Best way to do it is to start with the grub screw fully tightened and give the car a run then turn half the screw and keep repeating, to be true the figures between the 2 speed and the single speed are not that different, its hard to tell when the car changes gear. My friend has the same car and they both run completely different but the results are almost identical

Hope this help if you need more info send me an email