primary drive, and the main bearings. It is therefore essential that the correct oil level be maintained.     To check the gearbox oil level remove the level screw and filler plug, and pour oil into the filler until it just begins to flow from the level hole. Replace the screw after filling, having first checked the condition of its fibre washer. Fig. A2.     It is important that S.A.E. 40 grade oil be used, not any of the self-mixing oils recommended for the engine. As the clutch is lubricated from the same supply, special anti-friction additives should not be mixed with the gearbox oil.     Changing the oil in the gearbox is best done after a run, as the oil is warm and therefore more fluid. Take out the filler plug, and unscrew the drain plug underneath the gearbox. Allow all the oil to drain into a suitable receptacle before cleaning the gearbox with flushing oil. Replace the drain plug and refill the gearbox to the correct level as described above. The condition of the drain plug fibre washer is important; over-tightening will damage it. CONTACT BREAKER The contact breaker is mounted on the right-hand engine shaft and is housed within the primary

cover. It is essential that no engine oil is allowed into the contact breaker housing and to prevent this, an oil seal is fitted behind the contact plate.     Periodical lubrication of the contact breaker cam however, is necessary. Provision is made for this in the form of a grease-soaked wick.     The grease (preferably of the high-melting point type) should be applied sparingly to the wick every 5,000 miles (8,000 km.). Avoid using the grease excessively, otherwise the contact points may become contaminated, resulting in misfiring and difficult starting. REAR CHAIN It is a good practice to periodically remove the rear chain and clean it thoroughly in petrol or paraffin. When dry, gently warm the chain in a mixture of grease and graphite, allow to cool and wipe off any excess grease. Before replacing the chain, clean both the rear wheel and gearbox sprockets. Remember that the chain connecting link must be fitted with the closed end of the spring fastener pointing in the direction of chain travel (i.e., on the lower run of the chain, the closed end should be rearward).     See section H for further information. STEERING HEAD The steering head bearings are packed with grease on assembly and should only require repacking at the intervals quoted on page A2. Full details of removing and replacing the steering assembly can be found on pages E8 & E9 in the fork section.     Wipe out all the old grease from the bearing cups and clean the ball bearings by rolling them in a clean rag. After cleaning, carefully examine the bearings, cups and cones for pitting, corrosion or cracks, and renew if necessary. The fresh grease