Copperhead Concave System Setup and Troubleshooting

Small Grain

After Concave Installation:

  1. You must level the rotor to the newly installed concave. If not levelled, the thrashing ability can go down by as much as 50%. Refer to the John Deere operators manual for instructions on rotor levelling.
  2. Install all three cover plates and close them. In some tough crops a 4th cover plate may be necessary to remove or reduce white caps in the sample
    • NOTE: On older 70,60 and 50 series combines, it may be necessary to install the 3rd cover plate in the fourth position of the grate. This is where the return drops into the rotor and may affect the return thrash of the grain.
  3. Rear separation grates must be in the “up” position. Up means spacers are removed and stored in the “closed” post. This will help in the separation of grain from “MOG”.
  4. Download the John Deere GoHarvest App from the app store. This will provide basic set up settings for the rotor, chaffer, fan speeds, etc. and instruction on doing a POWER SHUT DOWN. A power shut down is the most important tool to assess what the combine is or is not doing. If a customer has not done a power shut down before, read the procedure.
  5. The most common overlooked problem is the top chaffer and bottom sieve is not inspected and not calibrated. INSPECT the bottom sieve. If one louver is out of adjustment, the white caps will go to clean grain and not the return. THIS is a VERY important first step!

In Field Problems:

White Caps

This is the most common complaint and the hardest to deal with

  1. Start by reducing the clearance of rotor to concaves. Increase the rotor speed by 50 rpm on every adjustment. Ex: Rotor adjustment from 4 to 3 on clearance. Adjust rotor speed up by 50 rom at a time.
  2. Make sure on the “S” series combines the re-thrasher is set to wheat, not corn.
    • Still White Caps in Sample
  3. Close down bottom sieve to put more unthrashed grain in the return for re-thrashing. INSPECT the sample in a bucket to see if the white caps are present at the bottom clean out cover. If white caps re still going into the clean tank close the bottom sieve and check return. The return should run at least 50% full on an S series for proper re-thrash.
  4. Increase rotor speed and reduce concave clearance.
    • Still White Caps in sample
    • YOU are maxed out on speed and clearance:
  5. Load machine up and do a Power Shut Down.


Things to look for with White Caps:

  • Look at the auger bed under rotor. Make sure you are getting a decent first thrash 95-98%. If the first thrash is bad a 4th cover plate may be necessary.
  • First thrash looks acceptable then inspect the return. ON “S” series with a re-thrasher you can inspect the top cross auger on the grain coming out of the thrasher. If white caps are present here then you may have worn segments in the rethrasher causing white caps. There should be little to no unthrashed grain in this area.
  • It may be necessary to install a Small Grain bottom sieve to help white caps to go to the return. Most people push back on this but it’s a small price to keep a clean sample. Most combines come with a standard tooth sieve.
  • Remember, it takes material on material to thrash properly.

Dirty Sample

  1. Power shut down. This is a must and is not to be skipped.
  2. After power shut down, inspect the grain and chaff in the auger bed and the top chaffer. The auger bed has plates you can raise and lower to move the material left and right in the machine. In most cases the right auger plate must be fully extended.
  3. Look to see if the top chaffer is loaded up on one side or the other. The side that is loaded up you may need to install the John Deere cover plates on the separation grates to move the material evenly across the top chaffer, if the extension of the auger plate does not evenly spread the material.
  4. Add fan speed after all the above procedures are done. Increase fan by 100 rpm. If you add the fan and the material on the chaffer is  not spread evenly, high loss of grain can happen.
  5. Slow down. A little goes a long way.
  6. If you have Harvest Smart use it. This will improve any sample and the grain quality. It will maintain an even flow into the machine.
  7. Close bottom sieve. Closing will reduce “MOG” in sample.
  8. Inspect the return auger. If full of chaff, increase fan by 100 rpm. increments.

If sample is still dirty and the fan is maxed out:

  1. Slow down. Some crops may have to be cut slower than others
  2. Make sure your fan is maxed out. Adjustments can be made to add more window on the fan adjustment screw to add more adjustment. Refer to John Deere on the proper adjustment.
  3. Top chaffer many have to be swapped out for a small grain or “short” chafer to help move more material out of the combine quicker.
  4. Cut as shallow as you can to help.
  5. Make sure all the cover plates on the rotor are closed to help keep straw from entering.