To help out another member who has lost parts of his kickstart mechanism on the road during a run, I have just stripped off the parts from my CW to take some dimensions etc. and find that the left hand thread on the end of the gearbox shaft retaining the ratchet mechanism is the same as that measured by Mike for the four speed box. I actually made it 0.453"x 20tpi. I wonder if this is another Douglas Special as this corresponds with 29/64". Chris.