Take off belt cover by taking out bolt from centre of cover and nut securing cover to primary chain case. Loosen clamping bolt securing dynamo strap to crankcase in front of cylinder base. Turn dynamo slowly on crankcase being careful not to move it sideways and put pulleys out of line. The armature is eccentric to the body of the dynamo, so that rotation of the body varies the distance of the armature spindle from the crankshaft. When belt is just taut tighten clamping bolt.

Check alignment of belt. Replace cover.