Check and Adjust Chopper Timing

Blade condition and timing can affect chopper system performance. The following observations while harvesting indicate poor system function:

• Trash (leaf) material is not cut cleanly making removal by extractors difficult.
• Stalks are not cut completely into billets.

Check Timing

1. CAUTION: Avoid serious injury or death. Shut OFF engine, remove key, and hang a “DO NOT OPERATE” tag in operator station. Wait for harvesting functions to stop completely before servicing chopper assembly.

   Park on a level surface, shut off engine, and remove key.

2. Open chopper gear case door.

3. Clean chopper drums, gear case, and surrounding area.

4. If necessary, install new blades. See Remove and Install Chopper Blades in Maintenance—As Required section.

5. 
   NW271000-UN-15MAY06

   Incomplete Cut Billets

   
   T8T1485-UN-16OCT14

   A - Upper Drum Assembly

   B - Blades

   Ensure that blades (B) are installed correctly as shown. Upper drum assembly (A) blades leads the lower blades as the cane is cut into billets.

---




6. 
   T8T2448-UN-07MAY15

   Chopper Flywheel (Style A)

   
   T8T4779-UN-31AUG16

   Chopper Flywheel (Style B)

   
   T8T2277-UN-23MAR15

   A - Flywheel

   B - Blade-to-Blade Contact Surfaces

   C - Upper Blade (as required)

   D - Lower Blade (as required)

   Rotate flywheel (A) clockwise and observe blade-to-blade contact. Drums must rotate smoothly.

---




7. Apply a light coat of quick-dry spray paint to the blade-to-blade contact surfaces (B) of each blade.

8. Rotate flywheel clockwise and allow upper and lower blades (C and D) to contact one another. Paint scratched or removed from blades shows blade contact pattern. Optimal blade-to-blade contact is when blades touch along entire length of the blade without the excessive impact.

Adjust Timing

1. 
   T8T2449-UN-07MAY15

   Chopper Gear Case Cover (Style A)

   
   T8T2453-UN-07MAY15

   Chopper Drive Gear (Style A)

   
   T8T4773-UN-31AUG16

   Chopper Gear Case Cover (Style B)

   
   T8T4774-UN-31AUG16

   Chopper Drive Gear (Style B)

   A - Flywheel

   B - Cap Screw (5 used)

   C - Upper Drive Gear Cover

   D - Cap Screw (6 used)

   E - Cap Screws (2 used)

   F - Position

   G - Adjustment Lever

   Remove cap screws (B) and upper drive gear cover (C).

   IMPORTANT: Cover opening when possible to avoid gear case oil contamination.

---




2. Loosen cap screws (D and E).

3. From the rear of machine, manually turn upper chopper barrel until upper and lower blades make proper contact.

4. NOTE: Slotted holes in upper drive gear are used to adjust chopper timing.

   Adjust upper drive gear to obtain smooth blade-to-blade contact along the length of each blade.

   1. Using a rubber mallet, tap adjustment lever counterclockwise until cap screws contact end of slots in gear, or as close as possible.

   2. Tighten two opposing cap screws in gear.

      NOTE: If further adjustment is needed, remove cap screw in slotted end of the adjustment lever and install into position (F).

   3. Repeat steps necessary to check blade contact.

5. When blade contact is correct, tighten cap screws (D and E).

6. Manually rotate the flywheel (A) clockwise and check chopper blade timing. Repeat adjustment steps if necessary.

7. After correct timing is achieved, tighten cap screws to specification.

   Item	Measurement	Specification
   Chopper Gear Case (Style A) Cap Screws (D and E)	Torque	520 N·m (383 lb·ft)

   Item	Measurement	Specification
   Chopper Gear Case (Style B) Cap Screws (D and E)	Torque	427 N·m (315 lb·ft)

8. Check gear case oil level and fill with recommended oil as necessary. See Check Chopper Gear Case Oil Level in Maintenance—Every 25 Hours or Daily section.

9. NOTE: If necessary, use a new upper drive gear cover gasket.

   Install gasket, upper drive gear cover, and cap screws. Tighten cap screws to specification.

   Item	Measurement	Specification
   Upper Drive Gear Cover Cap Screws (Style A and B)	Torque	70 N·m (51 lb·ft)

10. Close and latch gear case door.