Combines STS precleaner like tits on a boarIJ

As far as I know the first half of the pre-cleaner is supposed to act like a crash pan to give time for the grain and chaff to separate before getting a blast of air. That stepped part is solid and no air can get through. The wind comes through the fins just after it. It's supposed to separate better as a unit than just sieves. It must work because it sorts more material in a 9750STS than a 9600 does with more area. I think they did something like it on the CTS where half the pre-cleaner is covered up by a crash pan.

"Handy as a screan door in a submarine" - you are dead right. The pre-cleaner is a good idea but it should be adjustable. Fixed at 16mm with deep tooth sections is useless. You loose all capability of fine tuning this machine and take it bent over the bonnet when you get docked for to much mog. At the moment the only way out of it is to close down the bottom sieve to force more air pressure into the pre-cleaner but then you loose capacity and increase the amount going into the returns elevator. A very poor solution. JD has got (finally) adjustable pre-cleaners out on trial - when it comes into production is anyones guess. loewen and Harvestaire are going to clean up in the interim.

I haven't checked to see if the air actually gets to the front of the precleaner, or not, but what I do know is that the cleaning capacity is definitely the limiting factor on the STS. We have also been running the STS since 2000 and farm in North Central Alberta. We run a 9650 STS in wheat, barley, peas and canola, and usually run out of cleaning capacity before hp. I don't know why there is so much excitement about 400+ hp for the STS. If anyone knows how to increase the cleaning capacity, please let me know.

My 02 STS came with the fixed pre- cleaner when delivered new. I sent for and recieved the adjustable pre-cleaner from JD that is standard equipment in Europe. It actually came from Germany. Makes sense don't it............. All sts machines now come with the adjustable pre-cleaner as standard equipment.

We never ran anything out the back but sure could never clean up with our STS's. Just like everybody else, we closed down the bottom sieve until the return was full. If JD would get rid of their old fashioned mixers (augers) in the front and start separating the chaff earlier, would make a difference. NH does it and the lexions do it and both provide a much cleaner sample.

We tried the adjustable precleaner on our 2001 model and noticed no real improvement in performance or quality. If the precleaner sieve recieves no air then whether it is adjustable or not will make no difference. In stock factory form it is useless. I have wondered about taking those four stepped plastic shelves out from under the precleaner and perforating them with very small holes to allow the precleaner to function as a true sieve. Has anyone else considered or tried this on their combineIJ

I'm not a Deere man ,run a Gleaner so may be out in left field on this.looked at drawing on the Deere site of the pre cleaner,I think Deere needs to modify the air splitter and instead of pushing up through the pre cleaner,put a heavy blast over the top,grain mass will fall and the lighter stuff will be blown back.May be completely wrong just a suggestion.

First what I believe you are talking about is what Deere refers to as the "fixed front chaffer". In theory what is does is divert of good portion of the shoe load directly to the sieve. This undoubtably increases the tailings load as more MOG is dropped on the sieve that would normally be carried out by the chaffer, which could definitely be considered a con of this system. The pro of this system is that it distributes material to be cleaned more evenly between the chaffer and sieve allowing them to get more cleaning capacity out of a relatively small shoe for the overall combine capacity. If and when Deere comes with an adjustable front chaffer I have no doubt that the number of complaints of grain loss over the chaffer will increase exponentially as most folks will run it much tighter than the current fixed one is set, thus increasing the load on the chaffer. I'd have to run an adjustable front chaffer in the field under some high yielding crops and see what effect different adjustments had on overall shoe performance before I got too excited about it. One thing I would like to see is better blast of air at the front of the shoe where is can do the most good and also some more fan capacity. This isn't strictly a Deere complaint but why can't the combine manufacturers put a a real fan on any of these combinesIJ You can do more good with air than any adjustment on the chaffer or sieve will ever make. Give me a fan that I can get the chaff out of the combine before it ever hits the cleaning shoe!!!!! Gleaner is probably about the closest to this but it's still not enough in my opinion. Maybe someday I'll get fed up enough to tear into this problem on my own....ala Mark Underwood! He had some guts.

Are you sure 2003 STS now come with a adjustable pre-cleanerIJ I was on the Deere site, looking at 2003 changes and did not see it. I did see they are offering deep tooth chaffer and sieve.

No in fact I'm not sure. I was told by a JD rep. that it was but I did not look at it myself. I was kinda pressed for time and spent most of it at the New Holland display. CR970 looks very impressive. I think JD will be back in the catch-up mode again.