CONFIDENTIAL TIBU4005-00

PROBLEM: Saw speed may not recover adequately.

Perform the following checks and tests to improve the saw speed recovery performance.

I. Mechanical Checks

A. Tooth Wear: Tooth cutting thickness starts at 2 5/16" and should be changed when reduced to 2 1/8". Look for wear or burnt wood marks on the disc or on the bolt-on segments (if equipped) that indicates teeth are worn below the level of the saw blade.

B. Clearances: Top edge of teeth should clear the top of the tree support plate by 1/4" to 1/8". The bottom of the tree support plate chamfer should be below the top edge of the teeth. The saw should turn smoothly, should have no vibration and should not contact the tree support plate or other parts of the frame. Components should be in alignment.

Remove debris between the tree support plate, the saw disc and the saw frame base.

II. Operation Checks

A. Check Operation Procedures

Refer to SEBU7501, 533/543 Operation & Maintenance Manual, "Operating Technique Information".

Approach trees with the felling head tilted 3 to 5 degrees forward. Cut and grab tree. Lift and tilt back head slightly. Use the felling head to guide the tree to the ground rather than to handle the tree to the ground.

B. Do not rely solely on the pressure gauge to indicate that the saw is ready to cut. Also listen to the saw frequency sound to get a sense of when the saw is ready to cut.

Use appropriate cutting techniques for the size and type of wood. Trees larger than 22" in diameter should be double cut.

III. Check Hydraulic System Settings & Performance

In the future, the following service manuals will be updated to include the testing and adjusting information detailed below:

RENR6163, 533/543 Machine Systems Testing & Adjusting

RENR6343, HF202/HF221/HF222 Hydraulic System Testing & Adjusting

RENR6235, TK370/TK380 Machine Systems Testing & Adjusting

A. Test the Saw Performance

Note: The following information is based on a AVSpare/Timberking feller buncher and a AVSpare/Timberking felling head with: (1) a 30 GPM maximum displacement sleeve in the saw motor and (2) a one-piece disc. Some machines may be equipped with a different sleeve in the saw motor that changes the flow setting. Some machines may also be equipped with a heavier bolt-on segment disc that changes the disc inertia. Saw performance may vary depending on the equipment and operating conditions.

1. Run the machine to warm the coolant and hydraulic oil to normal operating temperatures.

2. Lower the head to the ground, set the parking brake and install the transport guard onto the head.

3. Install a phototach to measure the saw speed.

4. Install 0 ? 6000 psi pressure gauge onto the test port for the saw motor inlet pressure. Use the shortest possible test hose to ensure an accurate reading. The test port is located on the saw motor.

5. Increase the engine speed to high idle.

Illustration: Typical Saw Performance Curve for a AVSpare/Timberking Wheel Feller Buncher with a AVSpare/Timberking Felling Head

6. Turn on the saw and bring the saw to full speed. The saw should perform according to the following specifications:

a. Stage 1: The saw pump is upstroking and the saw motor is at maximum displacement. This stage lasts for 12 to 15 seconds. The motor inlet pressure reads 3950 +/- 50 psi (A).

b. Stage 2: The saw pump is at maximum displacement and the saw motor is destroking. This stage lasts for 15 to 18 seconds. The motor inlet pressure reads 3600-3700 psi (B).

c. Stage 3: The saw pump is at maximum displacement and the saw motor is at minimum displacement. The motor inlet pressure falls significantly. The saw reaches a full speed of approximately 1175 RPM (C).

If the motor inlet pressure is not within the specification for stage 1 only, adjust the saw pump outlet pressure. Refer to "Piston Pump (Disc Saw) ? Test & Adjust".

If the motor inlet pressure is not within the specification for stage 2 or for both stage 1 and stage 2, use the following procedure in place of "Saw Motor Compensator ? Test & Adjust":

i. Install a 0 ? 6000 psi pressure gauge onto the test port for the saw motor compensator pressure. The test port is located on the saw motor. Also install a 0 ? 6000 psi pressure gauge onto the test port for the saw pump outlet pressure. The test port is located on the saw pump. Use the shortest possible test hose to ensure an accurate reading.

ii. Block the saw.

iii. Lower the saw pump pressure to 3700 psi.

iv. Adjust the saw motor compensator pressure to 600 psi.

v. Raise the saw pump pressure to 3975 psi.

vi. Repeat the saw performance test.

vii. If the motor inlet pressure in not within the stage 2 specification of the saw performance test, repeat steps i ? vi, changing the pressure in step iii in 50 psi increments above or below 3700 psi until the saw performs according to the stage 2 specification

If the saw does not reach full speed in stage 3, adjust the saw speed using the procedure in "Disc Saw Speed ? Test & Adjust".

Additional notes for machines that are differently equipped:

If the saw motor is equipped with a sleeve for higher maximum displacement than the factory setting of 30 GPM:

-- Stage 1 will be slightly longer than the specification,

-- Stage 2 will be slightly shorter than the specification,

-- Stage 3 will be slightly shorter than the specification, and

-- Additional horsepower will be used in the saw circuit.

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

B. Adjust the Saw Speed

Refer to the following service manual stories to set the saw speed:

RENR6163, 533/543 Machine Systems Testing & Adjusting, "Disc Saw Speed ? Test & Adjust".

RENR6343, HF202/HF221/HF222 Hydraulic System Testing & Adjusting, "Disc Saw Speed ? Test & Adjust".

RENR6235, TK370/TK380 Machine Systems Testing & Adjusting, "Disc Saw Speed ? Test & Adjust".

C. Adjust the Saw Pump Pressure

Refer to the following service manual stories to set the saw pump pressure:

RENR6163, 533/543 Machine Systems Testing & Adjusting, "Piston Pump (Disc Saw) ? Test & Adjust".

RENR6235, TK370/TK380 Machine Systems Testing & Adjusting, "Piston Pump (Disc Saw) ? Test & Adjust".

D. Adjust the Saw Motor Compensator Pressure

Refer to the saw performance test information in this publication for updated information to adjust the saw motor compensator pressure. In the future, the following service manual stories will be replaced with the new test procedure described in this publication:

RENR6163, 533/543 Machine Systems Testing & Adjusting, "Saw Motor Compensator Pressure ? Test & Adjust".

RENR6343, HF202/HF221/HF222 Hydraulic System Testing & Adjusting, "Piston Motor (Disc Saw) ? Test & Adjust".

RENR6235, TK370/TK380 Machine Systems Testing & Adjusting, "Saw Motor Compensator Pressure ? Test & Adjust".

IV. Check Saw Hydraulic System Components

A. Saw Pump ? If the saw pump pressure cannot be adjusted to 3975 psi, the pump compensator may not be functioning properly. If saw pump pressure is at 3975 psi, but the saw speed of 1175 RPM cannot be reached, the pump may not be upstroking or destroking properly or may have system leakage. If the saw pump does not appear to be stroking when the maximum angle screw is adjusted, turn the screw all the way out, all the way in and then back out to the setting. Be careful not to exceed the maximum saw speed limits.

B. Saw Valve ? If the saw hydraulic system settings change, check saw valve cartridges for damaged o-rings and backup rings or for other leakage

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