Ok this ones for the JD guru's out there. Tips and tricks for eliminating rotor loss in the STS series combines with the Bullet rotor in heavy yielding wheat 100+ bu/a.......................lets hear it.
No offense taken, I really like the Case IH rotors, in fact I demoed one last year along side the 9660 STS. Our main crop is Alfalfa Seed and the Case threw it all out the back of the machine while the 9660 did an outstanding job. I wish that all we raised were the three crops that they build these machines for (Corn, Soybeans, and Wheat) It would make life allot easier when it came down to choices, but in our case they have to work in a big variety of crops, which is why the STS ended up under our shed.
All of those previous comments or proposed solutions have some merrit. From my years of experience with the STS in all sorts of crops, they do an excellent job in corn/beans & other crops when it is relativley easy to thrash & separate. I tried many things to get them to perform in all sorts of crop conditions - & they will certainly perform when conditions are right but are a supreme pain in the neck when it's not. Firstly I came to the conclusion that thrashing the grain out properly & in the first instance, was the STS's biggest problem. All you have to do is do a "stall test" to see the where, what & how, it's not happening. You will notice a large proportion of unthrashed heads & part heads all throughout the machine & particularly in the returns elevator. Notice the returns monitor is always at least half way accross the monitor? That material is going back through the rotor for another "thrashing" - all amongst a new lot of material that has come up the feeder - you speed the rotor up to thrash out the heads, then you have rotor loss - sound familiar? JD concaves have the cross bar set low to the wire so there is not much room to catch grain, or enough time to catch grain - whilst the rotor is running at 850-1000 RPM - so it's out the back. The cross bars need to be higher to give it a chance. I put in Loewen "low wire" concaves - all three & made sure they were level & correctly zeroed. Changed thrashing elements to Loewen - you may not have to do this as the new JD elements have rasps on them. Threw all concave covers & cage covers in the shed. Fitted adjustable pre-cleaner. Pressuming you have all the header, feeder & feed acellerator set correctly - For wheat, concave 15-20. Rotor 680-750. Pre-cleaner 10-12mm. Chaffer 16mm. Seive 6mm. Fan 1100-1200 (50 series - '60 & '70 will be less) It is amazing the differance. The STS will certainly perform in all sorts of conditions & crops.
If the wheat is not real hard to threash, we use the round bar concave (all 3) and 3 or 4 sets of interupter inserts and remove all the separator cover plates. With this set-up rotor loss is very low and you should be able to push near 15 acres/hour in 100 bu wheat.
I've just found this site, so this is my first msg. I have done my fair share of hours on a JD STS cutting all types of crops. If it was me setting up the combine for those conditions, without seeing or "feeling" the crop this is what I would start at.
1 small wire concave in the front, 2 large wire in the back.
Rotor at 900+. I have thrashed wheat with the bullet rotor at 1000 and haven't had issues with crack. The bullet dosen't thrash as hard the old type, which is a weakness in a lot of situations.
Concaves around 10, and probably opened a little farther.
Fan, 1000+. I like to run a lot of air, in those heavy conditions you will need it.
Top sieve at 16.
Bottom 6, if sample was fair.
A few years ago I really liked the STS series, however they are a hard combine to set up to do a good job all the time. A good buddy of mine went to the opposition and has not looked back.
Really appreciate the knowledgeable responses so far, they sound like some really good ideas to try. I've only run the STS for about 3/4 of a season now and still have corn to go before I'm done for the year. So far the only thing I don't like is when conditions get really tuff the rotor makes some alarming noises. I've only sheared the concave adjuster pin once but why only once is beyond me. Thanks guys, if you have other successful settings please share them.
Guys, beware of these sieve setting numbers. We found on our 9870's this morning after physically measuring both that the indicator number in the cabs are different, yet the measurements of the sieves are the same. We may have a potentiometer issue with one of these machines but nonetheless just be carefull using some of these suggestions without checking. And we did do calibrations on both of them this morning FYI.