Maintenance - Major Service

14-3. Check the drum rear brake

Note that the brake pedal height can be altered as required by setting the screw and locknut beneath the stop lamp rear switch; the pedal should be set so that it is as close as possible to the rider's foot in the normal riding position.

Adjustment is made by placing the machine on its center stand with the rear wheel clear of the ground, then tightening the adjuster nut at the rear end of the brake operating rod while spinning the wheel until a rubbing sound is heard as the shoes begin to contact the drum. From this point slacken the nut by 3 - 4 turns until the rubbing sound has ceased. This should produce free play of 1 5 - 25 mm (0.6 - 1.0 in) at the brake pedal tip.

Brake shoe friction material wear can be checked by reference to the external wear indicator (see accompanying illustration) attached to the brake camshaft. With the brake correctly adjusted and fully applied, the pointer should align with the 'Max' line cast on the final drive case. As the shoes wear, the pointer will gradually move downwards. lf it aligns with the 'Min' line at any time or extends beyond it, the brake shoes are worn out and must be renewed. See Chapter 9 - Wheels & Brakes.

Note that if the rear brake appears spongy or imprecise at any time, but especially after the wheel has been disturbed, it is possible that centralizing the brake components on the hub will effect an improvement. Slacken the rear wheel mounting bolts then spin the wheel and apply the rear brake firmly; maintain firm pressure while the mounting bolts are tightened securely to the specified torque setting.

At regular intervals check that the operating linkage is at its most efficient by ensuring that the angle formed between the brake rod and operating lever is less than 90' when the brake is firmly applied. lf the angle is more than 90' at any time, the brake will not be as efficient; the operating lever must be removed from the camshaft splines, noting the position of the wear indicator pointer, and repositioned on the camshaft so that the angle is correct. This may require some trial and error to achieve the correct setting. Ensure that the operating lever is correctly refitted end securely fastened, that the wear indicator pointer is correctly aligned and that the brake is properly adjusted.


Drum rear brake wear limit marks

A = Maximum friction material thickness
B = Minimum friction material thickness