St1100 Fork Tool Compress


To rough check a frame for correct alignment, see Fig. 2E-1. The dimensions shown will provide basic information to determine whether a frame is enough out of alignment to require a major realigning job or replacement.

Straightening a badly bent frame requires special tools and fixtures for holding, bending and gauging. If frame straightening facilities are not available locally, damaged frames may be returned to the factory for repair (through authorized Harley-Davidson dealers only).

Replace all badly bent or broken frames. The cost of repair would be prohibitive.


Harley Davidson Frame Drawings

Figure 2E-1. Frame with Basic Dimensions



All forks are basically comprised of two sets of telescoping tubes that work against springs, with an oil filled (hydraulic) dampening mechanism to control the action. The unit is engineered to give long service with a minimum of repair. Usually, only periodic (approximately 5000-mile intervals) oil change is necessary.

DUO-GLIDE (NON-ADJUSTABLE). The non-adjustable Duo-Glide fork, as illustrated in Fig. 2F-3, is for use on a solo motorcycle. The fork "trail" (the distance, at ground level, from the fork stem axis to a perpendicular through the wheel axle) is set and cannot be adjusted. This fork may be recognized by the two hexagon head upper bracket bolts (3, Fig. 2F-3) in the slider tube tops.

DUO-GLIDE (ADJUSTABLE). The adjustable Duo-Glide fork is for use on a motorcycle which operates with and without a sidecar. It is essentially the same as the non-adjustable fork except it has a two-position bracket that allows the trail to be changed for best solo or sidecar-equipped operation, also a steering damper adjusting mechanism which dampens the steering head to suit conditions and rider preference. All other adjustments and repairs are made exactly as on the non-adjustable fork. This fork may be recognized by the reversible bracket bolt washers, bolt and stem design (18, 19, 20, Fig. 2F-4) as described in "Adjusting Front Fork Trail."

SERVI-CAR (NON-ADJUSTABLE). The Servi-Car fork is a combination of the above forks. It has greater trail than the non-adjustable Duo-Glide fork, but is itself non-adjustable. The stem and bracket are the same as the adjustable fork except for the bracket bolt washers. In appearance, it is similar to the adjustable fork.


DUO-GLIDE (NON-ADJUSTABLE). Remove upper bracket bolt (3, Fig. 2F-3) at top of each fork tube.

DUO-GLIDE (ADJUSTABLE) AND SERVI-CAR. Remove fork cover side panels and fork filler screws (23, Fig. 2F-4).

ALL MODELS. Remove drain plug, Fig. 2F-3 at the outside bottom of each slider tube with a 3/16 in. Allen wrench and drain. Draining speed will be increased by gently flexing the fork as it empties. Replace drain plugs and pour 6-1/2 oz. of Harley-Davidson Hydra-Glide Fork oil into each tube, 7oz. if fork has been disassembled and washed. Measure amount very carefully. Flow of oil into tubes will be increased if fork is worked up and down during filling operation. Replace upper bracket bolts and tighten securely.

The fork filling device shown in Fig. 2F-1 will hasten and simplify the filling operation. The unit consists of a Neoprene (not rubber) stopper to fit the hole in the top of the fork, a length of flexible tubing, a funnel and an appropriate size can, soldered to the top of the funnel.

To make a filler can, drill a dozen 1/4 in. holes in the bottom of a one quart tin can (2), near the outside edge. Shape the bottom of the can with a light hammer so that it is dished upward to assure complete draining of oil through the holes.

Fork Slider Cover Cans

1. Bail

2. Filler can

3. Tin funnel

4. Metal tubing

5. Flexible tubing

6. Metal tubing

7. Rubber plug

8. Fork tube cap

Figure 2F-1. Fork Filler Can Components

Head Studs

Figure 2F-2. Filling Hydraulic Fork with Oil


1. Upper head bearing cover

2. Head bearing nut

3. Fork upper bracket bolt and valve (2)

5. Fork upper bracket cover

6. Handlebar and fork bracket

8. Fork bracket clamping stud (2)

9. Fork bracket with stem

10. Fork slider cover (2)

11. Slider tube plug (2)

13. Damper valve stud lock nut (2)

14. Fork slider tube (2)

15. Slider tube snap ring (2)

16. Damper tube bushing gasket (2)

17. Damper tube lower bushing (2)

18. Damper valve stud gasket (2)

19. Damper tube valve (2)

21. Spring ring washer (2)

22. Upper oil seal felt washer (2)

25. Slider upper and lower bushing (2 each)

26. Head bearing (see item 7)

27. Lower head bearing guard

Figure following name of part indicates quantity necessary for one complete assembly.

Figure 2F-2. Filling Hydraulic Fork with Oil

Select a tin funnel (3) with the funnel mouth about the same size as the bottom of can (2). Swage and shape the funnel spout so that a piece of 1/4 in. metal tubing (4), about 2 in. long, (a piece of fuel line is suitable) can be soldered into it. Solder (3) onto the bottom of (2). Improvise and attach bail (1) to the filler can.

Make plug (7) from a rubber bottle stopper purchased from a drug store. Rubber stopper should be 1 in. to 1-1/8 in. long, and its largest diameter about 5/8 in.

Hold rubber stopper in vise and drill a 3/32 in. hole lengthwise through the center. Then enlarge the hole with a 1/4 in. drill. After hole is drilled in the stopper, insert a 1/4 in. rod through the hole and grind the stopper to a 5/8 in. diameter at the large end, and slightly under 1/2 in. diameter at the small end, straight taper between ends, to form the plug.

Slightly flare one end of apiece of 1/4 in. tubing (6), about 2 in. long and insert into plug (7). Attach filler can to plug with transparent flexible tubing (5) about 2 feet long. See Fig. 2F-2.

Push the plug into the filler hole in fork top, Fig. 2F-2. Pour exact amount of oil into can. Work fork up and down. Air escaping through oil in filler can as fork is pushed downward will cause the oil to bubble violently, but because the bottom of the can serves as a baffle, no oil will be lost. Compressing the fork forces air out, releasing it draws oil into fork.

After the can appears to be empty, allow several minutes for can to completely drain then work fork once more. This assures getting into fork side the full quantity of oil poured into can.


If hydraulic fork does not work properly; that is, if it leaks oil or lacks original snubbing action, check the following before disassembling-

If oil leaks from vent hole in upper bracket bolt (3, Fig. 2F-3 and filler screw 23, Fig. 2F-4) when fork flexes, check for over-filling. Drain and refill with exact amount of oil.

Fork Slider Exploded View
Figure 2F-3. Hydra-Glide Fork - Exploded View
Fls Harley Fork Damper

1. Steering damper adjusting screw

2. Spring

3. Spider spring cover

4. Spider spring

5. Pressure disc (2)

6. Friction washer (2)

7. Anchor plate

8. Friction washer (see item 6)

9. Pressure disc (see item 5)

10. Fork stem nut

11. Upper head bearing seat

12. Upper bracket bolt and washer (2 each)

13. Upper bracket cover

Figure following name of part indicates

14. Upper bracket

15. Head bearing (2)

16. Slider tube plug (2)

17. Bracket clamping stud (2)

18. Bracket with stem

19. Bracket bolt with nut and cotter pin

20. Bracket bolt washer (2)

21. Bracket

22. Fork tube and slider assembly (2)

23. Filler screw (2)

24. Filler screw valve (2)

25. Filler screw washer (2)

necessary for one complete assembly.

Figure 2F-4. Adjustable Fork - Exploded View

Figure 2F-5. Fork Rebushing Tools





Fork Breathervlave

Figure 2F-5. Fork Rebushing Tools



If oil leaks from vent hole in upper bracket bolt when fork tubes contain correct amount of oil, check breather valve in upper bracket bolt or hole. To replace breather valve, place bolt in vise and tap back three stake locks with small punch and hammer. Pry valve from recess with length of stiff wire. If unable to free valve, drill hole in valve larger and pry valve out with small pin or screwdriver. In some cases, it is necessary to drill and tap hole in valve and pull it out with tap. Insert new valve assembly and stake three spots on bolt lip.

If fork action is stiff or soft and spongy and breather valves are functioning and oil content is correct, damper valves in fork tubes are inoperative. Fork must be disassembled. If fork is submerged in water, oil must be replaced at once. Water will rust damper tube valve parts. In neglected cases, the valves may stick and result in almost no snubbing action.

If oil bypasses slider tube bushings and leaks at top of sliders, bushings are worn and must be replaced. To replace slider bushings, fork must be disassembled. If slider bushings are worn, water will contaminate oil. Oil will appear emulsified, aerated and light brown.

If fork slider has play on slider tubes, bushings are worn and must be replaced. Fork must be disassembled. However, it is not necessary to disassemble entire fork and steering head unless desired.


If necessary repairs involve only sliders and slider tubes, the entire fork need not be disassembled.

To remove sliders and slider tubes, proceed as follows:

Remove front wheel as described in "Wheels," Section 2C. Remove front brake hand lever coil clip on fender. Turn off axle sleeve nut and pivot stud nut, and pull brake side cover and shoe assembly plus axle sleeve off fork. Remove front fender.

Loosen fork bracket clamping studs (8, Fig. 2F-3 or 17, Fig. 2F-4). Remove the two upper bracket bolts with oil seals (3 and 4, Fig. 2F-3; 23, Fig. 2F-4). Pull fork slider and slider tube assemblies out bottom of slider covers.

Proceed with fork slider and slider tube disassembly and repair as described in a following paragraph, "Disassembling Front Fork."


The slider only may be removed without disassembling remainder of fork assembly as follows:

Remove front wheel axle as described in "Wheels", Section 2C, and fender mounting screws from slider.

Right slider may be removed after turning off damper valve stud lock nut (13, Fig. 2F-3).

To remove left slider, first remove wheel, brake drum and brake side cover as described in "Disassembling Front Fork Slider and Tubes" above, and damper valve stud lock nut (13, Fig. 2F-3).


Turn steering damper adjusting screw (1, Fig. 2F-4) clockwise to apply dampening action and counterclockwise to reduce dampening action. Apply steering damper only when operating under conditions where some degree of dampening stabilizes steering.

It is best to keep the damper set a little snug when operating with a sidecar.


To adjust fork trail for use with sidecar, turn off nut on bracket bolt (19). Tap bolt head back far enough to pry out washer (20). Grasp fork tubes and pull forward sharply. It may be necessary to loosen upper bracket bolts (12) to move fork forward or backward. Revolve bracket bolt washers 180 degrees until pin on washer is forward. Seat washer pin in slot in bracket (21) boss. Tap bracket bolt (19) into position and turn on nut.

To adjust fork for solo riding, follow same procedure except push fork tubes back and insert washer (20) so pins are rearward.


Prepare for disassembling by raising front end of motorcycle on stand or suitable support, so wheel is off the floor.

Remove front and side fork trim panel. Remove

Remove front and side fork trim panel. Remove

Bmx Fork Removal Handlebar

Figure 2F-6. Removing Fork Slider Bushing headlamp mounting nut. Disconnect at terminal strip the two headlamp wires and all wires that pass through handlebar. Disconnect throttle and spark advance cables from carburetor and circuit breaker.

Remove front wheel as described in Section 2C. Remove front brake hand lever bracket and coil clip on fender. Turn off front axle sleeve nut and pivot stud nut, and pull brake side cover and shoe assembly and axle sleeve off fork. Remove front fender. Slider bushing play can best be checked at this point. Remove the four nuts, handlebar riser caps and handlebar.


Remove upper head bearing cover (1) and bearing nut (2). Remove the two upper bracket bolts (3) with oil seal (4) and upper bracket cover (5). Lift off handlebar and fork bracket (6). Remove upper head bearing (7) and pull fork out bottom of steering head.

Loosen fork bracket clamping studs (8) and slide fork bracket (9) off fork tubes with fork slider covers (10). Turn out two slider tube plugs (11) and invert sliders to drain out oil and remove fork springs (12).

Superbike Fork Special Nut
Figure 2F-7. Driving in Fork Slider Bushing
Head Studs

Figure 2F-9. Indicating High Point out of bracket (21). Slider tube and slider disassembly is the same as described for non-adjustable fork.


The front fork slider bushings (25, Fig. 2F-3) may be replaced using three special tools.

1. Part No. 96255-50, Fork Slider Bushing Puller.

2. Part No. 96285-50, Bushing Driver and Guide.

3. Part No. 96300-50, Bushing Reamer and Pilots.

Figure 2F-8. Reaming Replacement Bushing

Remove damper valve stud lock nut (13) from bottom of slider and pull slider tube (14) out of slider (24). Pinch out snap ring (15) from lower end of slider tube and drop out damper tube lower bushing (17). Discard gaskets (16 and 18). Slide out damper valve assembly (19). Snap out spring ring (20), washer (21), felt washer (22) and pry out oil seal (23).


Prepare for disassembly as described in paragraph above. Turn out steering damper adjusting screw (1) and lift out parts 2 through 9. Parts 5, 7 and 9 may be loosened by inserting a screwdriver tip between parts and prying upward.

Turn off stem nut (10) and bearing seat (11) using Cone Lock Nut Wrench, Part No. 96219-50. Remove upper bracket bolts and washers (12) and lift off bracket cover (13) and upper bracket (14). Lift out upper head bearing (15) and slip fork assembly out of frame steering head.

Remove slider tube plugs (16) and loosen clamping studs (17). Slip fork tube and slider assembly (22)

Figure 2F-9. Indicating High Point out of bracket (21). Slider tube and slider disassembly is the same as described for non-adjustable fork.


The front fork slider bushings (25, Fig. 2F-3) may be replaced using three special tools.

1. Part No. 96255-50, Fork Slider Bushing Puller.

2. Part No. 96285-50, Bushing Driver and Guide.

3. Part No. 96300-50, Bushing Reamer and Pilots.

REMOVING SLIDER BUSHINGS. Position fork slider in vise as shown in Fig. 2F-6.

Remove spring ring, steel retaining washer and felt wiper from slider upper end. Pry out oil seal with large screwdriver.

Install Fork Slider Bushing Puller, Part No. 9625550, so the three claws expand inside the tube under the upper, or shorter bushing. Place puller cap in oil seal counterbore, apply oil to screw threads and steel washer. Turn nut down against puller cap and use engine sprocket wrench on nut to extract bushing. See Fig. 2F-6.

Remove lower bushing in the same manner.

INSTALLING FORK SLIDER BUSHINGS. New, replacement bushings are installed with Fork Slider Bushing Driver and Guide, Part No. 96285-50.

Wash out fork slider and lubricate slider bore with engine oil. Position new lower bushing in bushing driver guide to compress bushing, then place driver guide with bushing in slider oil seal counterbore as shown in Fig. 2F-7.

Drive bushing through the driver guide into fork slider. Bushing is positioned correctly in slider bore when second groove from top on driver is flush with top edge of driver guide. Do not drive bushing deeper than specified, or it will collapse enough so it cannot be finish-reamed.

Install upper bushing in the same manner lower bushing was installed. Drive it into slider until lower groove on driver is flush with top of driver guide. This positions upper bushing 1/16 in below slider oil seal counterbore.

REAMING BUSHINGS. The Fork Slider Bushing Reamer with pilots, Part No. 96300-50, is used to ream the bushings to finished size.

Attach long pilot to reamer as shown in Fig. 2F-8. The long pilot fits into the unfinished lower bushing, acting as a guide, while reaming the upper bushing. Do not drop reamer into bushing. Slowly lower reamer into cutting position and ream bushing, turning reamer clockwise. Continue turning reamer clockwise as it is being extracted when cut is finished.

Remove long pilot from reamer and attach short pilot. Finish lower bushing in same manner as upper bushing. Use caution when passing reamer cutters through the upper bushing.


Clean and air dry all parts. Inspect outside of slider tubes and inside of slider for scratches, grooves, nicks and scoring. Minor burrs may be taken off with a fine oil stone. Replace all badly worn parts.

Inspect damper tube valve parts for rust and broken

Inspect damper tube valve parts for rust and broken

Arbor Press For Aircraft Damping Valve

Figure 2F-10. Pressing High Point springs. Replace broken springs and all valve parts that are deeply pitted or otherwise in unusable condition.

Inspect slider tube plug for loose or displaced fork upper baffle cups and broken spring. Solder loose cups in place and replace any broken parts. Be sure cups are arranged with slots for oil passage on alternate sides. Improper arrangement may cause oil leak at upper bracket bolt.


Straightening fork tubes requires several special tools including hydraulic or arbor press, dial indicator and straightening blocks. If facilities are not available locally, fork tubes may be returned to the factory for straightening.


Repair fork tubes must be sent to the factory through an authorizedHarley-Davidson dealer.

Never attempt to straighten a fork tube that has a sharp angle bend. It should be scrapped because the metal is stretched.

Before beginning the straightening operation, clean the fork tube. Locate bends with dial indicator. A fork tube is usually bent in two or three places, seldom only one. Place fork tube on straightening blocks. Correct bend in tube with an arbor or hydraulic press.

Bicycle Fork Straightening Tool Images
Figure 2F-11. Pressing Fork Tube Round
Round Tube Straightening
Figure 2F-12. Correcting Bracket Bow

Find the highest point out of round with a dial indicator (Fig. 2F-9) and mark with chalk. Press high point as shown in Fig. 2F-10. Repeat indicating and pressing operations until tube is within .003 in. to .004 in. of being straight.

Sometimes fork tubes are out of round, especially at the point it is clamped in the fork bracket. Place tube in straightening blocks and press until perfectly round as shown in Fig. 2F-11, checking with dial indicator and micrometer. Finally, check tube by inserting in new fork slider. Work tube up and down. If it does not bind, it is straight.


Straightening a fork stem and bracket assembly requires a great deal of skill, experience and several tools and fixtures. Special tools necessary include Fork Tube Straightening blocks, Part. No. 96246-50, four blocks are needed; Bending Bar, Part No. 96806-40; Fork Stem and Bracket Aligning Gauge, Part No. 96245-51. In addition, the following pieces of bar stock are needed: Two bars, 1-5/8 in. diameter, about 12 in. long; two bars 1 in. x 4 in. x 12 in. (approximately); assorted pieces of rectangular bar stock to use in transmitting arbor press pressure to unit to be straightened.

If facilities are not available locally, fork stem and bracket assembly may be sent to factory for straightening providing it is not badly bent or broken.


R.epair fork stem and bracket assemblies must be sent to factory through authorized Harley-Davidson dealers.

To straighten stem and bracket, proceed as follows: Insert the two 1-5/8 in. x 12 in. bars in fork bracket

Figure 2F-13. Straightening Two Twisted Legs

1067784 Fork And Stem Assembly

Figure 2F-14. Checking Bracket Alignment and secure with two clamping studs. Sometimes the bracket is so badly bent that the bars cannot be inserted. In this case, press the bars into place with an arbor press, then press on the front edge of bracket to correct the "bow" distortion as shown in

Fig. 2F-12. Repeat pressing until bars are loose in bracket.

operation along edge

A bracket assembly is usually out of alignment along the horizontal centerline, with one or both legs bent.


Reference to vertical and horizontal centerlines applies to bracket and fork stem as positioned on arbor press (see Fig. 2F-12).

If both legs are twisted, place bracket assembly on arbor press as shown in Fig. 2F-13 with blocks placed under two low legs only (A and B). With press block placed across bracket and bar assembly, press until high legs (C and D) are in alignment.

If one leg is bent, place bracket and bar assembly on three straightening blocks, two blocks under straight leg and one block under low end of other leg. Place press block diagonally across bracket assembly to high leg until high leg is forced down and into alignment with the other three leg ends.

Place the fork stem and bracket assembly on the four straightening blocks located on the surface plate (see Fig. 2F-14). If the legs rest squarely on straightening blocks, the bracket assembly is correctly trued on a horizontal plane. If bracket is not true, press again, checking alignment after each operation.

Use a square to check if bracket assembly is bent, distorted or out of parallel on a horizontal plane as shown in Fig. 2F-15. Place bracket and bar assembly in a heavy vise and straighten using the Bending Bar.

Check fork stem alignment with Fork Stem and Bracket Aligning Gauge as shown in Fig. 2F-16. Use Bending Bar to bring stem into position. Recheck the fork completely.


Replace upper oil seal (23) and felt washer (22) in top of fork slider. Wash chips and oil from fork slider and position new oil seal in counterbore. Drive oil seal into counterbore and against seat with driver and mallet as shown in Fig. 2F-17. Drive with light blows and stop immediately when seal has bottomed.

St1100 Seating Position
Figure 2F-16.

Checking Stem Alignment with Gauge

Figure 2F-15. Bending Bracket Legs Parallel 2F-10

Insert spring ring washer (21) and spring ring (20). Position spring ring so its gap is directly over water drain hole in slider top.

Clamp a length of about 1 in. steel rod upright in a vise so that 13-1/2 in. extends above top of jaws. Assemble damper valve (19) with gasket (18), lower bushing (17) and lower bushing gasket (16). Make sure all of old gasket is removed before installing new part. Invert slider tube over length of rod in vise and drop damper valve assembly in place. Install snap ring (15) in notch provided in bottom of slider tube. Check clearance between snap ring and lower bushing. If clearance exceeds .004 in., remove snap ring, gasket and lower bushing and insert additional shims to bring to a maximum of .004 in. clearance.

Lubricate outside of slider tube with fork oil and slip slider assembly down over slider tube. Turn lock nut (13) on damper valve stud extending out bottom of slider. Work slider to check for bind. If bind is present, release lock nut, rotate slider 180 degrees and reassemble. Fasten fork slider covers (10) to fork bracket (9), and slip fork bracket over slider tubes. Adjust so 5-1/16 in. of slider tube extends above top of fork bracket and temporarily tighten bracket clamping studs (8).

Pour 7 oz. of Harley-Davidson Front Fork Oil into each slider tube, insert fork springs (12) and turn in slider tube plugs (11).

Press lower head bearing guard (27) and greased lower head bearing (26) onto stem. Install stem in steering head on motorcycle. Grease and position upper head bearing (7), handlebar and fork bracket

Figure 2F-17. Inserting New Oil Seal

(6), bracket cover (5). Securely tighten slider tube plugs. Loosen bracket clamping studs (8) and rotate slider tubes so flats on slider tube plugs are to the sides of the fork assembly. They must be in this position to have the slider tube plugs function properly. Tighten bracket clamping studs.

Turn on steering head nut (2), until there is noticeable drag in bearing when lock is turned - then loosen nut enough so lock turns freely and install bearing cover (1) with two screws. Slip plug oil seal (4) on upper bracket bolt (3) and screw into slider tube plug. Replace handlebar, caps, and locking nuts. Reassemble motorcycle in reverse order of disassembly.


Follow procedure described for non-adjustable front fork except for the following points:

1. Position slider tubes in bracket (21) so top of slider tube is exactly 5-1/16 in. above top of bracket, and flat surfaces on slider tube plugs are directly toward side of motorcycle with filler screw (23) toward rear of fork.

2. Before tightening fork stem nut, loosen bracket clamping studs (17) so slider tubes may find a position in bracket (21).

Assemble remainder of fork and steering head in reverse order of disassembly.

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