Pre-Harvest Combine Adjustments

September 18, 2026

A combine-harvester that is optimally adjusted will improve its efficiency, reduce field losses for a successful harvest in 2026!

Key adjustments

Header

  • Make sure the knives (blades) of the cutter bar are sharp and in good operating conditions;
  • Make sure the edges of the cross auger are sharp;
  • Lower the cutter bar for low-podded plants and dry conditions;
  • Auger clearance: 5/8 inch, or 15 mm above the platform;
  • Opt for a floating flex header and automatic reel height control to allow the header to shave the ground when harvesting soybeans avoiding the collection of soil;
  • Choose the slowest possible forward ground speed recommended by the manufacturer.

Threshing and seed separation

  • Adjust the reel spacing and reel cylinder speed to be about ~25% faster than the ground speed;
  • Add belts to the reel or use an air assist reel for faster loading of the platform/table;
  • Reduce the spacing between the reel, the cutter bar, the cross auger and the feeder house;
  • Adjust the concave.

Feeder house drum

  • Make sure the feeder house drum is properly adjusted to keep the flow as efficient as possible;
  • Slow its speed to between 0.5 and 1 mi/hr in the areas where harvesting might be risky;
  • It is crucial to make sure that the chains and bearings are properly lubricated and maintained at the recommended intervals. The belts must be tightened and checked regularly.

Cleaning and maintenance

  • Remove the perforated trapdoors under the elevators, the cross augers or the unloading augers;
  • Check the auger bearings for wear and tear to prevent droop and pinched beans;
  • Adjust fan speed by “Fine-Tuning” the airflow;
  • Open the chaffer (upper sieve) wide enough, say 5/8”, to prevent grain from being carried to the tailings system;
  • Open the lower sieve just a little, between 1/4” and 3/8”, to allow the clean grain to be carried to the tank rather than the tailings system.

What to do if the beans are small

  • Turn down the fan and reduce the spacing in the chaffer and sieve;
  • Reduce the spacing in the mulcher;
  • Increase the speed of the reel to (between) 10 and 25% more than the travel speed;
  • Reduce the space between the reel, the cutter bar, the auger and the feed house chain, to make sure the stalks go through the header and enter the feed house.