Front Forks

XJ750RH Front Fork Disassembly/Reassembly

The XJ750RH front fork has a top and bottom bushing for the inner tube to ride in (reducing friction). Since the top bushing is pressed into the top of the outer tube, it is necessary to remove the oil seal before the inner tube may be removed from the outer tube. The procedure is as follows:

CONVENTIONAL FORK

XJ750RH FORK

Disassembly

1)    Disconnect the speedometer cable and brake calipers and remove the front wheel. Place a wooden wedge or other object into the caliper assemblies to prevent the brake pads from falling out. Remove the front fender.

2)    Release air from forks by depressing air valve stem.

3)    Remove plunger case securing bolts and remove plunger case from anti-dive unit.

4)    Loosen pinch bolts on triple clamps holding inner tube.

5)   Slide inner tube from triple clamp until air valve ring can be removed (Note: Apply even pressure to both sides of ring during removal) and remove wire ring from inner tube.

6)    Remove fork leg.

7)    Remove dust cover, circlip and washer from the outer tube.

Note: Do not damage the inner tube surface during dustcover removal.

8)    Remove rubber cap from top of inner tube.

9)   The spring seat and spring are retained by a stopper ring. Depress stopper seat and remove stopper ring.

10)  Remove spring seat and fork spring. 

Note: Do not drain fork oil.

11)  Reinstall air valve ring on inner tube.

12) Set the inner tube with approximately 50 mm travel at end and completely fill with fork oil.

13)  Reinstall spring seat and stopper ring.

14) Slightly depress inner tube and hold air valve stem until all air is bled from fork.

15)  Using a press, slowly contract the inner tube in the outer tube until oil seal comes out or oil leaks from outer portion of oil seal.

Note: If the inner tube is abruptly contracted or if air remains in the inner tube, the oil may spurt out or the oil seal may spring out. Never touch the inner tube during disassembly.

16)  Remove stopper ring and spring seat then drain oil.

17)  Remove oil seal from top of inner tube.

18)  Remove alien bolt from bottom of outer tube.

19)  Hold the fork leg horizontally, securely clamp the axle mounting boss of the outer tube in a vice with soft jaws, and remove bushing from top of outer tube by carefully but forcefully withdrawing the inner tube.

Note: 1) Excessive force will damage the bottom and/or the top bushing. Damaged bushing must be replaced. 2) Avoid bottoming the inner tube in the outer tube during the above procedure, as the oil lock valve assembly will be damaged.

Reassembly

Before reassembling, clean and inspect all parts and replace when necessary. Bottom Bushing Installation

1) Install using only tapered end of inner tube to expand bush.

2) Reinstall compression cylinder in inner tube and, with assembly inverted, assemble washer, wavy washer and collar on projection of compression cylinder and install in outer tube.

Note: Place outer tube over inner tube assembly when installing to prevent washers and collar from coming detached.

3) Install alien bolt through bottom of outer tube and torque to specification using Locktite.

Note: Allen bolt torque — 2.0 kg-mm — Use Locktite When tightening alien bolt, be sure to align anti-dive hole in outer tube and oil lock piece hole.

Top Bushing Installation

4) Install top bushing as per the following two steps:

a)  Use large special tool for temporary installation of bushing in outer tube.

b)  Complete installation using both small and large special tools.

5) Install "L" section washer on top of bushing and then install oil seal with numbered side up, using special tool (part number TLM-11080-10)

6) Install washer and circlip then install dust cover using special tool.

7) Pour specified amount of oil into inner tube.

Note: Front fork oil (each): 309 cc (10.4 oz.) Recommended oil: SAE 20W After filling, slowly pump the fork up and down to distribute oil.

8)    Install spring, seat and stopper ring.

9)    Partially install fork under triple clamp then install wire ring and air valve ring.

10) Slide fork leg up and tighten triple clamp bolts.

11)  Install front fender, front wheel brake calipers and speedometer cable.

12) Reinstall plunger case.

Warning:

When reinstalling the plunger case, use utmost care to free the inside of the case from any mineral oils (eg. engine oil, fork oil, etc.). Otherwise, such oils will deteriorate the actuating piston o-ring, with the resultant leakage of the brake fluid'.

Note: Tightening torque: 0.4 mm-kg (2.9 ft-lb — Use Locktite)

Maximum Air Pressure: 2.5 kg/cm2 (36 psi). Do not exceed this amount.

Special Tool

Part Number TLM-11080-10

This tool will be available from the Yamaha Parts Department around August 1981.