Adjusting Row Unit Drive Sprockets With Fixed Speed Drive (Combines)
494 Corn Heads are driven from the right-hand side only and includes two 32-tooth sprockets as standard equipment.
Corn heads driven from both sides - 592, 594, 692, 693, 694, 892, 893, 894, 1092, 1290 and 1291 which include two 27-tooth and two 32-tooth sprockets set at 1:1 ration as standard equipment. 1293 corn head has two 18-tooth and two 22-tooth set at 1:1 ratio as standard equipment.
NOTE:
Drain oil and remove pan before changing or adjusting sprockets, see Remove/Install Oil and Pan in Service section.
When operating at increased speeds, install small sprocket on drive shafts on one end and large sprocket on driven shafts on the other end.
NOTE:
On 494 corn heads, an additional sprocket must be purchased from your John Deere dealer.
Add or remove links from drive chain as necessary. Adjust tightener so chain will operate without climbing or jumping sprockets.
The following chart gives the approximate combine travel speed that is used with each sprocket combination.
NOTE:
Recommended travel speed in chart is based on average field conditions. Your particular field condition may differ and determine which sprocket must be used.
| When Combining at: |
Right-Hand Shaftsa |
Left-Hand Shafts |
| |
|
|
| |
Drive |
Driven |
Drive |
Driven |
Under 5 km/h
(3 mph) |
27-tooth |
32-tooth |
27-tooth |
32-tooth |
5 to 7 km/h
(3 to 4 mph) |
27-tooth |
27-tooth |
32-tooth |
32-tooth |
over 7 km/h
(4 mph) |
32-tooth |
27-tooth |
32-tooth |
27-tooth |
| a(Only on 494) |
|