Changing the Motor's Chain Drive Sprocket
Remove the battery, then place the bike on a stand or upside down as here and remove the chainguard securing bolt shown. This is it's only securing bolt
Then lift the lower part of the front of the chainguard to disengage the two securing tongues from the black metal support plate as shown at the left.
The chainguard can then be disengaged from the upper securing tongue and, moved forward and lowered to leave it hanging. As you see on the right, there is no need to remove the crank or pedal.
You then see the chain path with the motor sprocket in the middle between chainwheel and jockey wheel.
Split the chain in the normal manner and remove it from the motor sprocket, then use circlip pliers as shown at the right to remove the securing circlip. The sprocket will then slide off the splines easily for a new one to be fitted. Replace the circlip with the pliers and push it home so that it engages fully with it's groove in the shaft.
Refit the chain, engage the upper tongue of the chainguard and then the two lower tongues, then finally replace the rear securing bolt with it's nylon washer.
Job done.
Job done.
9.12.2007
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TIP If you get caught out with a worn motor sprocket starting to jump the chain at a time when you cannot immediately get a new sprocket, no problem. Just reverse the sprocket on the splines of the shaft so that the unworn tooth face is driving the chain. This will keep you going for a considerable while until you can get a new sprocket.
Clarke circlip pliers from Machine Mart, online or from their branches.
Clarke circlip pliers from Machine Mart, online or from their branches.