Take off the two nuts securing the bottom vertical bevel bush housing to the crank case. Tap the housing slightly from side to side to free it and draw it right up off the studs. Note the number of paper joint washers fitted between face joints so as to know how many to fit when re-assembling. Loosen and remove the ball valve nut from the end of the mainshaft: this nut is a left-hand thread. As it is removed it will expose the ¼-in. ball and the ball valve spring. Be careful not to lose the ball or damage the spring, which should be carefully pulled out from the end of the main-shaft. Take off the small tongued washer which is fitted over the mainshaft behind the ball valve nut. A small claw extractor will now be necessary to draw the magneto and pump driving pinion off the shaft. This pinion is not keyed. Finally, carefully prise off the bottom bevel pinion from the mainshaft - this can usually be done without difficulty by two small levers or screwdrivers. This pinion is a parallel fit on the shaft and is keyed in place. Note that there may be thin packing shims used behind this pinion for meshing purposes, and these should be retained for use when re-assembling.