Dismantling and Reassembling. Drain out all oil. The drain plug is underneath the gearbox. It is unnecessary to remove the gearbox from the machine to dismantle it, and it is easier to leave it in position. Take out the three bolts holding the kick start housing B.K.4 to the gearbox end cover. Pull out the housing complete with the kick start crank and ratchet B.K.1 4. Unless it is required to change the kick start spring B.K.19 do not dismantle the ratchet from the housing. Unscrew and remove the gearshaft end bearing cap B.3 from the gearbox end cover. Take off the hexagon nut from the end of the shaft and remove the rear chain cover and rear chain. Tap the gearshaft into the box about an inch. Take out all the end cover bolts and disconnect the gear rod from the outside striking lever. Take off the nuts from the ends of the selector bars. The ends of the bars protrude through the end cover. It will now be possible to remove the end cover. Hang up the packing washer out of harm's way till needed when refitting.
Now draw out the two selector bars. If the nuts are threaded back on to the bars they will serve as a seating for levering out of place. Alternatively, if a piece of steel about I" thick, and long enough to span across to the gearbox housing, is drilled to fit over the bars, the nuts can be packed with washers and when screwed down will draw the bars out. the low gear will pull off the end of the gearshaft and the middle gear B.78 with selector fork B.K.26 may be taken out after the gearshaft has been pulled out from the clutch end of the gearbox. Lift the bottom selector fork until the peg is disengaged from the track in the cam plate B.K.80 which will allow the layshaft complete with fork to come out. The two end gears on the layshaft are a tight press fit and are difficult to remove without a press. There should, however, be no necessity to disturb them. On machines fitted with close ratio gears when a 17T sleeve gear B.6/3 is fitted, the layshaft driving gear B.86/2 (27 teeth) will only disengage from the sleeve gear in one position. It will therefore be necessary to turn the layshaft round until this one position is found. This is on account of the teeth of the top-gear " pick up " masking the sleeve gear teeth. Similarly, the layshaft can only be refitted in this one position. To remove the cam plate or the striking mechanism, first take out the pivot bolt and indexing pawl spring. Undo the nut securing the outside striking lever to the spindle. If the end of the spindle is now tapped into the gearbox the striking plate and cam plate will be removable from inside. Re-assembly is simply a reversal of the operations described above. Do not take down the foot gearchange mechanism unnecessarily. Difficulty might be encountered in assembling correctly again.