The 1982-1987 Yamaha RD125, DT125 LC repair manual by Haynes, covers the following enduro (dual-purpose) models:

• Yamaha RD125 LC, introduced June 1982
• Yamaha RD125 LC II, introduced Feb. 1985
• Yamaha RD125 LC III, introduced Nov. 1986
• Yamaha DT125 LC, introduced Apr. 1982
• Yamaha DT125 LC II, introduced Feb. 1985
• Yamaha DT125 LC III, introduced March 1986

Book Excerpt: 1982-1987 Yamaha RD125, DT125 LC Repair Manual ROUTINE MAINTENANCE

ADJUSTING AND GREASING THE STEERING HEAD BEARINGS The handling and road holding characteristics are to a great degree dependent upon the condition of the steering and suspension components. Although any sudden change will be immediately apparent to the rider, the gradual deterioration in performance caused by general wear can often be overlooked and deficiencies may not be apparent unless the machine is ridden close to its limits. A regular and systematic check can, therefore, avoid unpleasant surprises on the road. Roll the machine backwards and forwards with the front brake held on, noting the action of the front forks. These should operate smoothly and progressively and should show no signs of bouncing due to ineffective damping. Any signs of knocking felt through the handlebar or heard are often traced to slack or worn steering head bearings. To check for wear, place the machine on its centerstand and place blocks or a crate beneath the crankcase so that the front wheel is raised clear of the ground. Persuade a friend to grasp the lower end of the fork legs and push and pull them. If play is present in the bearings it may prove easier to feel than see, by placing a finger between the frame headstock and the bearing shroud. To adjust the steering head bearings, slacken the top bolt at the center of the upper fork yoke. Using a C-spanner, slacken the adjustment nut by about a half turn, then slowly tighten it until a slight resistance is felt. It is very easy to overtighten the bearings, and this can cause stiff steering and rapid bearing wear. It is necessary to just eliminate free play and no more. When adjustment is complete check that the steering moves easily from lock to lock, then secure the top bolt to lock the adjustment. Any play remaining in the front end will probably be due to wear in the fork legs, and if found these should be overhauled as described in Chapter 5, Sections 2, 5 and 6.

WHEELS, BRAKES AND TIRES

FRONT DISC BRAKE: OVERHAULING THE MASTER CYLINDER

1. The master cylinder forms a unit with the hydraulic fluid reservoir and front brake lever, and is mounted by a clamp to the right-hand side of the handlebars.
2. The unit must be drained before any dismantling can be undertaken. Place a suitable container below the caliper unit and run a length of plastic tubing from the caliper bleed screw to the container. Unscrew the bleed screw one full turn and proceed to empty the system by squeezing the front brake lever. When all the fluid has been expelled, tighten the bleed screw and remove the tube.
3. Select a suitable clean area in which the various components may be safely laid out, a large piece of white, lint free cloth or white paper being ideal.
4. Remove the locknut and the brake lever pivot bolt to free the lever. As it is lifted away note the small spring which is fitted into the end of the lever blade. Release the front brake switch by pushing a small screwdriver blade into the hole beneath the master cylinder extension which houses it. The switch can now be withdrawn.
5. Remove the two bolts which hold the master cylinder clamp half to the body and then lift the master cylinder away. Remove the cover and empty the reservoir. It if is still connected, remove the banjo bolt and free the hydraulic hose from the master cylinder body.

Subject: 1982, 1983, 1984, 1985, 1986, 1987 Yamaha RD125, DT125 LC service, maintenance, repair. ISBN-10: 1850104174 | ISBN-13: 9781850104179 | Haynes 887