“Maximize” Your JD 9600

The term “maximize” suits the subject at hand: John Deere’s 9000 series “Maximizer” combines. John Deere is one of the few manufactures that still builds a conventional combine. Demand for these machines is of particular interest to the mixed farmer, as baling straw is a necessity on most farms where livestock is part of the operation. For all intents and purposes this article could apply to most of the conventional combines produced, with minor changes made for other makes and models. As in previous articles in this series, we’ll start at the front of the combine and work backwards.


John Deere builds its own pickup, which is a 9000 series three-roller belt pickup with plastic teeth. Strong points of a JD factory pickup are durability, serviceability, simplicity and ability to operate at moderate to high speeds. Challenging points would be less than optimal results in a thin or rained-into-the-ground crop (situations that challenge most pickups), and if you have a lot of small stones or rocks the pickup has a tendency to “flick” them onto the swath and then into the machine. You can mount non-OEM style pickups, such as a Victory, Swathmaster or Rake-up, on a John Deere header if you feel these units perform better in your area or crop conditions.

John Deere’s straight-cut headers (Models 925, 930 rigid and flex) have a good reputation and their overall function and durability is great. In a traditional auger-style header, the auger flighting needs to be in good condition and the stripper bar behind the auger should not be worn significantly. It should be adjusted as close to the auger flighting as possible without touching the flighting. As mentioned in previous articles, draper style headers perform very well. JD has its own draper header (the “D” series) and adapters are available to mount Honey Bee or MacDon headers.


A poorly adjusted feeder chain and worn out floors in feeder houses are the main inhibitors to good flow. Excessively worn feeder chains and sprockets accelerate wear significantly, especially if you replace sprockets and have a worn chain or vice versa.


Flow is sometimes an issue in a conventional combine. Good flow and a good threshing job do not happen by chance. A number of key components need to be in good condition to achieve flow and do a good job.

These are:

Rub bars. Make sure your bars are in good condition. If there is more than five mm (a bit less than a quarter inch) of variance, this is too much. If you dislike changing rub bars, consider installing chrome bars as they will last three times longer than standard bars.

Concave. The tolerance of five mm stands true for the concave. This again is the MAXIMUM tolerance. If you have worn con-caves and rub bars, you are doubling the overall slack in the threshing area.

Install a wide-wire concave. A wide wire concave with filler bars will do an excellent job of threshing in almost all crops and will allow for good seed recovery. This will increase the capacity and flow of the combine more than another other one thing you can do.

Set the tolerance to near zero at the back of the concave. The front opening will vary depending on what you are threshing. You want rub bars and the concave closer together for hard to thresh cereals and wider for small grains, oilseeds, pulses, etc. Refer to your factory settings and go from there.


Inspect the rear beater vanes for wear or damage. If they are damaged or worn, consider replacing the vanes. You can also buy aftermarket deep vane beaters that claim to increase aggressiveness and capacity.

There is not much to go wrong with straw walkers, but when things do go wrong…well, it’s not pretty and let’s leave it at that. It is very important to make sure that the walker blocks or bushings are in good condition as well as the cranks. If either the cranks or bushings are worn excessively, the walkers will be pounding and will eventually break. It is not difficult to check the condition. Get underneath the walkers and push up on them. If there is very much play at all, you should investigate further. Adjustments will usually rectify the situation, but if worn excessively, the cranks or bushings may need to be replaced.


Inspect the stationary and rotating blades on the straw chopper. Choppers take anywhere from 15 to 30 horsepower to drive. The better condition the blades are in, the less power the chopper will require and the better job it will do.


The engine is the heart and lungs of your combine. Feed it good food (good quality fuel, clean fuel filters and clean injectors/fuel delivery system), give it lots of clean air (good clean air filter) and service it regularly.


Conventional combines work the best when they are full. This stands true for all combines, but with conventional combines it is a “one shot” process in the threshing area. Most of the threshing occurs when grain rubs against grain, therefore if the combine is not running full, a poor thresh will result. You’ll get unthreshed heads and a dirty grain sample. Sometimes the answer to poor throughput and performance is to push further forward on the speed control.

Charlie Smith owns Combine World in Allan, Sask. For feedback on this article or questions about combines in general, you can contact him at [email protected]or at 1-800-667-4515.

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