HF181, HF201 and HF221 Felling Heads Caterpillar

If the performance of the saw is lagging, perform this procedure before any other adjustments are made on the felling head.

Note: The machines are equipped with a 115 L/min (30 US gpm) maximum displacement sleeve inside the saw motor and a one-piece disc saw blade. Some machines may be equipped with a different sleeve inside the motor that changes the flow setting. Some machines may be equipped with a disc saw blade with heavier bolt-on segments that changes the inertia of the disc saw blade. The performance of the saw may vary depending on the equipment and operating conditions.

Table 1

Required Tools
Part Number	Description	Quantity
9U-7400	Multitach Tool Group	1
198-4240	Digital Pressure Indicator	1

Show/hide table

Personal injury can result from rotating and moving parts. Stay clear of all rotating and moving parts. Never attempt adjustments while the machine is moving or the engine is running unless otherwise specified. The machine must be parked on a level surface and the engine stopped.

1. Prepare the machine for adjustment.

   ReferenceTesting and Adjusting, "Preparation for Troubleshooting".

2. Warm the hydraulic oil to normal operating temperature. Normal operating temperature is 45 °C (115 °F) to 70 °C (160 °F). Use the following procedure in order to warm the hydraulic oil.

   1. Operate the engine at 1800 RPM to 2000 RPM.

   2. Move the boom up and down.

   3. Operate the tilt cylinder back and forth until you reach the normal operating temperature.

3. Lower the felling head to the ground. Shut off the engine.

Show/hide table



Illustration 1	g01035833

4. Install the transport guard on the felling head.

Show/hide table



Illustration 2	g01062117
(1) Bolt. (2) Access plate. HF221 is shown.

Show/hide table



Illustration 3	g02488676
HF201 is shown. HF181 is similar.

5. Remove bolts (1) from access plate (2) on the side of the felling head.

   Note: Hold access plate (2) in place when you remove the last bolt in order to keep access plate (2) from falling.

6. Remove access plate (2) . The weight of access plate (2) is 9 kg (19 lb).

Show/hide table



Illustration 4	g01062118
(3) Bolt. (4) Access plate. HF221 is shown.

7. Remove ten bolts (3) from access plate (4) on the front of the felling head.

8. Remove access plate (4) . The weight of access plate (4) is 23 kg (51 lb).

Show/hide table



Illustration 5	g00828879
Felling Head without plate (2) (G) Pressure tap on the displacement control valve.

9. Attach the 198-4240 Digital Pressure Indicator to pressure port (G) (discharge pressure port of the saw pump) that is on the machine.

   Note: Pressure port (G) will read system pressure of the saw. This pressure will be the output from the saw pump that is on the machine.

Show/hide table



Illustration 6	g01041471
Location of access hole for earlier felling heads except for the PAM and PAJ felling heads.

Show/hide table



Illustration 7	g02489876
Location of access hole for the PAM and PAJ felling heads.

10. Locate the access hole on the right side of the felling head. The access hole is behind the tree basket. Refer to Illustration 6 for earlier felling head.

    Note: The location of the access hole for the PAM and PAJ felling heads is behind the side access plate. Refer to Illustration 7. The side access plate has been removed for clarity.

11. Thoroughly clean the top surface of the disc saw in order to ensure the accuracy of the following test.

    Note: The disc saw has a shiny surface. The photo pickup may not be able to recognize the reflective tape. You may need to paint the top of the disc saw with a suitable black paint. Use 4C-5842 Flat Black or an equivalent, in order to obtain an accurate measurement from the reflective tape.

Show/hide table



Illustration 8	g01062119
(5) Magnetic base. (6) Wire to Multitach. (7) Reflective tape strip. (8) Photo pickup.

12. Place one 3 inch strip of reflective tape (7) on the surface of the disc saw. Position the tape so that the tape is perpendicular to the hub of the disc saw.

13. Install magnetic base (5) onto the base of the frame. Position magnetic base (5) at the edge of the access hole.

    Note: Ensure that you position wire (6) for photo pickup (8) so that wire (6) does not contact any moving parts or hot surfaces.

    Note: Position photo pickup (8) no less than 2 inches away from the reflective tape. Tighten the pinch bolt in order to prevent photo pickup (8) from falling into the access hole.

14. Observe the reading on the display of the 9U-7400 Multitach Tool Group . Record the speed of the disc saw.

15. Start the engine. Increase the engine speed to 2250 ± 10 RPM.

Show/hide table



Illustration 9	g01038016
The location of the switch for the disc saw in the old machines.

Show/hide table



Illustration 10	g01162335
The location of the switch for the disc saw in the new machines.

16. The switch for the disc saw must be activated in order to perform this test. Activate the switch for the disc saw.

Show/hide table



Illustration 11	g01035839
Performance Characteristic of the Saw (Typical Example) (A) The pressure of the saw pump at the inlet of the saw motor. (The saw pump is upstroking and the saw motor is at maximum displacement.) (B) The pressure of the saw pump at the inlet of the saw motor. (The saw pump is at maximum displacement and the saw motor is destroking.) (C) The maximum RPM of the disc saw

17. The performance of the saw should be to the following steps.

    1. (Stage 1) The saw pump is upstroking and the saw motor is at maximum displacement. This stage lasts for 12 to 15 seconds. Read the inlet pressure of the motor at port (G) . Refer to the "Adjust the Compensator of the Piston Pump (Disc Saw)" Table 2 for the machine that is being service on line (A) of the graph.

    2. (Stage 2) The saw pump is at maximum displacement and the saw motor is destroking. This stage will last for 15 to 18 seconds. Read the inlet pressure of the saw motor. Refer to the "Adjust the Compensator of the Saw Motor" Table 3 for the machine that is being service on line (B) of the graph.

    3. (Stage 3) The saw pump is at maximum displacement and the saw motor is at minimum displacement. The inlet pressure of the saw motor falls significantly. The saw will reach full speed. Refer to the "Adjust the Speed of the Disc Saw" Table 5 for the saw speed on line (C) of the graph.

(Stage 2) If the inlet pressure at the saw motor is not within the limit, then adjust the pressure of the saw motor. Refer to the "Adjust the Compensator of the Saw Motor".

(Stage 1) If the inlet pressure at the saw motor is not within the limit, then adjust the pressure of the saw pump. Refer to the "Adjust the Compensator of the Piston Pump (Disc Saw)".

(Stage 3) If the disc saw does not reach full speed, then adjust the speed of the disc saw. Refer to the "Adjust the Speed of the Disc Saw".

If the saw motor is equipped with a sleeve for higher maximum displacement, the following occurs.

Note: The factory setting of the sleeve is 115 L/min (30 US gpm).

Stage 1 - The specification will be slightly longer.

Stage 2 - The specification will be slightly shorter.

Stage 3 - The specification will be slightly shorter.

Note: If the saw motor is equipped with a sleeve for higher maximum displacement, additional horsepower will be used in the circuit of the disc saw.

If the felling head is equipped with a disc saw blade with bolt-on segments, stages 1, 2 and 3 will be slightly longer than the specification. The inertia of the disc saw blade will be greater than the inertia of the one-piece disc saw blade.

Adjust the Compensator of the Piston Pump (Disc Saw)

The saw pump supplies oil to the saw motor. Check the discharge pressure of the saw pump with the IQAN control.

Show/hide table



Illustration 12	g01037785

1. Install the transport pin.

Show/hide table



Illustration 13	g00945274
The display in Illustration 13 is the small IQAN display. The display is used in old machines.

Show/hide table



Illustration 14	g01201729
The display in Illustration 14 is the large IQAN display. The display is used in new machines.

2. Start the engine. The main screen for the IQAN is shown in Illustration 13. Refer to Illustration 14 for the large IQAN screen. Activate the main menu by pressing button 1.

Show/hide table



Illustration 15	g00944098

3. Press the "ESC" button on the smaller IQAN display. The "Measure" screen will then be displayed. Press the function key F2 on the large IQAN screen in order to select the measure menu.

Show/hide table



Illustration 16	g00944100

Show/hide table



Illustration 17	g01209672

4. Press the "F1" button on the small IQAN display. The "Voltage In" screen is displayed. Press the "F1" button again in order to display the "Voltage In" screens. Rotate the knob in order to highlight Engine Speed and "Hyd" pressure on the larger IQAN display. Press the center of the knob in order to proceed to the next screen.

Show/hide table



Illustration 18	g00945279

Show/hide table



Illustration 19	g01257906

5. Press the "Up" button on the Small IQAN display. Scroll through the screens until the "Saw Pump Press" screen is displayed. The pressure of the saw pump will be displayed on the large IQAN display.

6. Increase the engine speed to 2250 ± 10 RPM.

   Note: The switch for the disc saw must be activated in order to perform this test. Activate the switch for the disc saw.

7. Read the pressure on the "Saw Pump Press" screen. Refer to Table 2 for the pressure setting of the saw pump for the machine that is being serviced. If the pressure is correct, proceed to Step 15. If the pressure is incorrect, proceed to Step 8.
   Show/hide table

   Table 2

   Normal Pressure Setting for the Saw Pump
   Machine	Pressure Setting
   TK700 Track Feller Buncher and TK1100 Track Feller Buncher	27600 ± 345 kPa (4000 ± 50 psi)
   TK711, TK721, TK722, TK732 Track Feller Bunchers	31025 ± 345 kPa (4500 ± 50 psi)
   1090, 1190, 1190T, 1290T Track Feller Bunchers	31025 ± 345 kPa (4500 ± 50 psi)
   TK1051 Track Feller Buncher	34500 ± 345 kPa (5000 ± 50 psi)
   TK741, TK751, TK752, 1390 Track Feller Bunchers	31025 ± 345 kPa (4500 ± 50 psi)
   500 Series Track Feller Buncher	31025 ± 345 kPa (4500 ± 50 psi)

8. Reduce the engine speed to low idle.

9. Shut off the engine.

10. Open the hood for the engine compartment.

Show/hide table



Illustration 20	g01062120
Saw Pump (typical example) (9) Compensator valve. (10) Pressure tap (discharge pressure). (11) Saw pump.

11. Connect the pressure gauge to pressure tap (10) .

12. Start the engine. Increase the engine speed to 2250 ± 10 RPM.

13. To adjust the discharge pressure of the saw pump, loosen the locknut on compensator valve (9) .

14. Turn the adjustment screw for compensator valve (9) until the pressure reading from pressure tap (10) reads the correct pressure for the machine that is being serviced.

15. Move the switch for the disc saw to the OFF position.

16. Reduce the engine speed to low idle.

17. Shut off the engine.

18. Repeat the test for the saw performance.

Adjust the Compensator of the Saw Motor

The following procedure adjusts the start of destroke pressure for the saw motor.

The saw pump supplies oil to the saw motor. The saw motor starts at maximum displacement. After the pump pressure to the saw motor drops from the maximum to the pressure of the compensator, the displacement of the saw motor decreases. The compensator pressure controls the shift point of the saw motor from maximum displacement to minimum displacement. The compensator pressure will be adjusted in this procedure.

Note: The following procedure requires two people. The procedure should be performed outside.

Show/hide table



Illustration 21	g00761676
(M) Pressure tap on the shuttle valve

1. Connect the pressure gauge to pressure tap (M) .

2. Start the engine.

3. Increase the engine speed to 2250 ± 10 RPM.

   Note: The switch for the disc saw must be activated in order to perform this test. Activate the switch for the disc saw.

4. Temporarily set the compensator valve of the saw pump on the machine to the pressure that is given in Table 3. Ensure that the pressure gauge at pressure port (G) reads the pressure that is given in Table 3. This pressure reading will be the output of the saw pump that is on the machine.

   Note: Refer to the "Adjust the Compensator of the Piston Pump (Disc Saw)".

   Show/hide table

   Table 3

   Temporary Pressure Setting for the Saw Pump
   Machine	Pressure Setting
   TK700 Track Feller Buncher and TK1100 Track Feller Buncher	25510 ± 345 kPa (3700 ± 50 psi)
   TK711, TK721, TK722, TK732 Track Feller Bunchers	28270 ± 345 kPa (4100 ± 50 psi)
   1090, 1190, 1190T, 1290T Track Feller Bunchers	28270 ± 345 kPa (4100 ± 50 psi)
   TK1051 Track Feller Buncher	31025 ± 345 kPa (4500 ± 50 psi)
   TK741, TK751, TK752, 1390 Track Feller Bunchers	28950 ± 345 kPa (4200 ± 50 psi)
   500 SeriesTrack Feller Buncher	28270 ± 345 kPa (4100 ± 50 psi)

Show/hide table



Illustration 22	g01062122
Back of the Saw Motor

Show/hide table



Illustration 23	g01037825
Displacement Control Valve

5. Remove cap (13) . Loosen locknut (15) . Turn adjustment screw (14) on displacement control valve (12) until the pressure reading from pressure tap (M) reads 6895 ± 170 kPa (1000 ± 25 psi).

   Note: The adjustment screw is sensitive. The pressure may rise from this pressure to a much higher pressure with little change on the adjustment screw. This increase indicates that the shift point for the motor has been reached. If the shift point of the motor changes, the performance of the saw will change.

6. When the correct pressure has been reached, tighten locknut (15) to a torque of 69 N·m (50 lb ft). Install cap (13) .

7. Reset the discharge pressure on the saw pump that is located on the machine. Reset the discharge pressure to the pressure that is given in Table 4.

   Note: Refer to the "Adjust the Compensator of the Piston Pump (Disc Saw)".

   Show/hide table

   Table 4

   Normal Pressure Setting for the Saw Pump
   Machine	Pressure Setting
   TK700 Track Feller Buncher and TK1100 Track Feller Buncher	27600 ± 345 kPa (4000 ± 50 psi)
   TK711, TK721, TK722, TK732 Track Feller Bunchers	31025 ± 345 kPa (4500 ± 50 psi)
   1090, 1190, 1190T, 1290T Track Feller Bunchers	31025 ± 345 kPa (4500 ± 50 psi)
   TK1051 Track Feller Buncher	34500 ± 345 kPa (5000 ± 50 psi)
   TK741, TK51, TK752, 1390 Track Feller Bunchers	31025 ± 345 kPa (4500 ± 50 psi)
   500 SeriesTrack Feller Bunchers	31025 ± 345 kPa (4500 ± 50 psi)

8. If the pressure at the inlet of the saw motor is not within the specification for Stage 2 of the saw performance test. Then repeat Steps 4 through 8. Adjust the pressure in Step 4. Use increments of 345 kPa (50 psi) above the pressure setting or below the pressure setting for the machine that is being serviced. Adjust the pressure of the saw pump until the specification is reached. If the pressure of the saw motor is within the specification, then proceed to Step 9.

9. Turn the switch for the disc saw to the OFF position.

10. Reduce the engine speed to low idle.

11. Shut off the engine.

12. Remove the hoses and pressure gauges.

Show/hide table



Illustration 24	g01062117
(2) Access plate. (1) Bolt . HF221 is shown.

Show/hide table



Illustration 25	g02488977
HF201 is shown. HF181 is similar.

13. Install access plate (2) with bolts (1) .

Show/hide table



Illustration 26	g01062118
(4) Access plate. (3) Bolt. HF221 is shown.

14. Install access plate (4) with ten bolts (3) .

15. Repeat the test for the saw performance.

Adjust the Speed of the Disc Saw

The saw pump supplies oil to the saw motor. The flow of oil from the saw pump controls the speed of the disc saw. The displacement of the saw motor cannot be adjusted. Use the following procedure to check the pump displacement. Two people are required for the following procedure.

Verify that the discharge pressure of the saw pump is correct.

Show/hide table



Illustration 27	g01037785

1. Remove the bolt and the nut from the transport pin. Remove the transport pin.

2. Start the engine. Turn the engine speed dial to full throttle. Turn the saw blade control switch to the ON position. Allow the disc saw to reach full speed.

3. Observe the reading on the display of the 9U-7400 Multitach Tool Group . Record the speed of the disc saw.

4. Refer to Table 5 for the speed of the disc saw. If the speed is not correct, proceed to Step 5. If the speed of the disc saw is correct, proceed to Step 8.
   Show/hide table

   Table 5

   Model	Saw Blade Configuration	Maximum Speed (RPM)
   HF181	Single Piece	1300
   HF181	Segmented	1250
   HF201	Single Piece	1250
   HF201	Segmented	1175
   HF221	Single Piece	1175
   HF221	Segmented	1100

5. Adjust the displacement of the saw pump that is on the machine.

   Note: The saw pump supplies oil to the saw motor. The flow of oil from the saw pump controls the speed of the disc saw.

Show/hide table



Illustration 28	g01062124
(16) Volume control.

6. Adjust the displacement of the saw pump. Adjust volume control (16) by loosening the locknut for the adjustment screw.

7. Turn the adjustment screw with a 7 mm hex wrench. Turn the adjustment screw clockwise in order to decrease the amount of flow to the saw motor. Turn the adjustment screw counterclockwise in order to increase the amount of flow to the saw motor. Repeat Step 3 through Step 4.

   Note: One full turn of the adjustment screw is equal to 4.1 cc/rev (.25 cu in/rev) or 109 RPM of the disc saw.

8. Turn the saw switch to the OFF position.

9. Shut off the engine.

10. Repeat the test for the saw performance.