Corn Head Angle 

The angle needs to be between 23 and 25-degrees for optimum performance in both standing and lodged corn. Put the combine on a level surface, then lower the corn head until the row frame is 2 inches off the ground. Place a magnetic protractor on the stripper plate and read the angle. If the angle is too steep, pull the top of the corn head toward the combine or push the bottom out, or a combination of both.


Check Lube Level in Gear Box

Use JD corn head grease to re-fill. The grease level should be above the spur hear seen through the top inspection plug (1-1 1/2inch below inspection hole – helpful to use a flashlight). The boxes should not be full of grease, as there has to be air for expansion and contraction of lube.


Adjust Auger

The auger should be adjusted to 1 ¾ inch clearance between flighting and tray to reduce ear slicing.


To Reduce Ear Toss

Move cross auger back as close as possible to feeder chain drum. Run feeder chain on fast speed for both corn and beans. Add half and full links to feeder chain. This reduces the dead air space between the cross auger and the feeder chain flighting. This reduces the height of the pile of ears between the cross auger and the feeder house, therefore reducing back feeding and ear toss.


Opening Stripper

Plates can reduce trash intake, but can also increase header loss. Beginning settings are 1 3/16 inch at bottom and 1 ¼ inch at the top, then adjust accordingly.


Oil Bath Settings

The 40/90 corn head should have oil bath in overdrive, the (big sprocket on the back (driver), and the little sprocket on the front(driven)).


40/90 Corn head gear ratios:

693 – 30 Driver & 25 Driven

893 – 30 Driver & 25 Driven

1293 – 22 Driver & 18 Driven

1290 – 22 Driver & 18 Driven


Used Gathering Chain Tighteners

Used gathering chain tighteners can occasionally lock up. This is caused when the spring vibrates and augers itself into the hole between the bolt and the flat strap. This can be fixed by adding a second washer at the bottom of the pipe spacer identical to the washer that is currently at the top of the pipe spacer. Apply anti-seize lubricant to the bolt threads for future adjustments.



Case IH cross augers have 4 inchs of flighting overlap in the center, and JD cross augers have none. We believe that 4 inches of overlap increases the traction and helps pull loose trash and fluff under the auger and into the feeder house. A small section of flighting can easily be welded onto the cross auger flighting to create this overlap. Use the reverse flighting on 30 foot split cross augers. In the past split cross augers had no reverse flighting The performance of the older auger is poor and we believe that it is due to this. You can purchase reverse replacement flighting alone, or new replacement augers with reverse flighting already attached from John Deere.


Plastic Gathering Chain Paddles

Attached to the gathering chain lugs will improve gathering and conveying performance in down corn.

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