Gear cable adjustment

Note whenever changing gears you should do so with the motor turning to give them the best chance of meshing easily. Remove the plug and  use pedals rather than the motor while adjusting!

In the 2-speed Quickly the gearbox selector is sprung towards second gear (selector plunger spring to full extension, fully out from the casing). The motor uses a single gearchange cable but if this is disconnected and the engine rotated it will automatically settle into 2nd gear. The cable is used to pull the selection plunger (attached to the gear fork internally) inwards. This movement selects in turn  neutral and then 1st. Changing back up 1st to neutral or neutral to 2nd or first to 2nd in one movement occurs under the restorative pressure of the spring inside the box. The cable limits the outward movement of the plunger according to the twistgrip position so it stops at neutral for instance or is permitted to keep  moving to 2nd, but the outward movement itself is driven by the internal gearbox spring.

The three speed box i more complex; a masterpiece of ad hoc adaptation. There was no convenient way to include a 3rd gear with gearchange mechanism and no room for a foot change so the extra gear was shoehorned in on an additional shaft and the gearchange mechanism modified to shift it. As seen above, in the 2 speed box the cable is required only to pull the gear selector inwards, outwards movement was accomplished by the spring pressure in the box. In the 3 speed box that internal spring has been removed and, since cables cannot push as effectively as they can pull, a second cable was required to pull the gear selector back in. The third gear was mounted on a separate shaft and the selector fork was modified to now engage with both shafts, however more movement was required to disengage second and reach the new gear beyond. 

The solution was cumbersome but effectively the two gear cables were combined into a double-length cable which wound around the twistgrip in its centre where it was located with a nipple. This meant that rotating the twistgrip would pull one side of the cable and push the other. In order to afjust the separate sides of the vable, each half had a separate adjuster. The selection plunger was replaced with a rocker unit into which both ends of the cable located so that twisting the twistgrip caused the rocker to pivot and this moved the modified fork along the selector shafts. Its a very complicated cable to make and very complicated to fit and adjust. My cable is already fitted and in good condition so I may write another section when I have to change it but for the time being I'm going toconsider only the adjustment. In my case the adjustment is off... the gears are all shifted one up from their indicated position on the twistgrip and first is hard to get. This seems to move about when I ride the bike so it's possible the cable is maybe stretched or the nipples are sliding but that would mean cable change so I'm readjusting first to see if this fixes it.

The motors normal position is still 2nd gear so the first step is to put the motor into 2nd gear and slacken the cables if necessary to get there. Put the twistgrip into the 2nd gear position. Using a pair of snipe nosed pliers grip the upper gear cable nipple on the rocking selector (under rhs magneto cover) and gently pull it back and forth. Adjust the upper cable (adjuster nearest the decompression lever) until the barrel nipple sits snugly in the rocker hook... it should not be under tension but have virtually zero play if you try to pull it away from the rocker.
Select first gear... the upper cable will retract pivoting the top of the rocker towards the casing. Check that 1st engages, if it doesn't then you may need to tighten (or possibly loosen) the upper cable by the smallest amount possible until it does.
At this point the bottom of the rocker has rocked fully outwards to its maximum distance from the case. Now adjust the lower cable until the barrel nipple sits snugly in its rocker hook... again not under tension but no slack either. This cable is the one used to pull bottom of the rocker back inwards to change up the gears so check that it does so and you can go back to 2nd, 0 and 3rd 
Adjust the lower cable if necessary to ensure that changing up happens.

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