The 1974-1984 Yamaha TY50, TY80, TY125, TY175 trials bike repair manual by Haynes, covers the following motorcycle models:

• Yamaha TY50 P (49cc), 1976-1977
• Yamaha TY50 M (49cc), 1977-1983
• Yamaha TY80 (72cc), 1974-1984
• Yamaha TY125 (123cc), 1982-1984
• Yamaha TY175 (171cc), 1975-1984

Note: this manual can also be helpful to owners of Yamaha-based trials specials.
Book Excerpt: 1974-1984 Yamaha TY50, TY80, TY125, TY175 Repair Manual FRAME AND FORKS

GENERAL DESCRIPTION The front forks are telescopic, coil sprung, with hydraulic damping, while the rear suspension consists of two coil sprung hydraulically - damped suspension units acting on a pivoted fork (swinging arm). The frame is all welded tubular steel of the full cradle type.
FRONT FORK LEGS: REMOVAL AND REFITTING

1. Place the machine securely on a stout wooden box or paddock stand so that the front wheel is clear of the ground. The front wheel can then be removed according to the instructions given in the relevant Section of Chapter 5.
2. Remove the four mudguard mounting bolts and then carefully withdraw the mudguard.
3. On TY80 models, the fork legs are retained in the top yoke by the fork top bolt. Remove the fork top bolts and the bottom yoke pinch bolts. It is then possible to slide the fork legs down and out of the yokes. Note that the top bolts should be slackened first, if the forks are to be dismantled.
4. If the fork legs are stuck in the yokes, apply penetrating fluid and attempt to rotate the legs by hand to free them. It may be necessary to completely remove the pinch bolts and to spring the clamps apart slightly with a large, flat-bladed screwdriver. Great care must be taken not to distort or to break the clamp, as this will necessitate replacement of the complete yoke. If the leg is still reluctant to move, push a metal bar of suitable diameter through the spindle lug in the fork lower leg and tap firmly downwards on the protruding end of the bar to drive the fork leg from the yokes.
5. Once the legs have been removed, put them to one side to await stripping and examination. If they are not to be dismantled, ensure that they remain upright so that no fork oil is lost.

WHEELS, BRAKES AND TIRES

WHEEL BEARINGS: REMOVAL, EXAMINATION AND REFITTING

1. Remove the wheel from the machine as described in previous Section of this Chapter, lift away the brake back plate and withdraw the spacer and sealing cap (if fitted) from the opposite side of the hub. On TY50 P models, flatten back the tab washers, unscrew the sprocket retaining bolts and lift away the free wheel hub and the sprocket.
2. Position the wheel on a work surface with its hub well supported by wooden blocks so that enough clearance is left beneath the wheel to drive out the left-hand bearing. Ensure the blocks are placed as close to the bearing as possible, to lessen the risk of distortion of the hub casting while the bearings are being removed or refitted.
3. Place the end of a long-handled drift against the upper face of the left-hand bearing and tap the bearing downwards out of the wheel hub. The spacer located between the two bearings may be moved sideways slightly in order to allow the drift to be positioned against the face of the bearing. Move the drift around the face of the bearing while drifting it out of position, so that the bearing leaves the hub squarely.

Subject: 1974, 1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984 Yamaha Trials TY50, TY80, TY125, TY175 service, maintenance, repair. ISBN-10: 0856964646 | ISBN-13: 9780856964640 | Haynes 464