6620 6 row narrow head in 193 bpa corn... several questions

John_PA

Well-known Member
I ran down a bunch(about 22 acres) of 100-160 bushel corn on the toxic farm and the combine did good. it put a lot of cob tips in the bin, but the FM was 1.100 on the elevator ticket, so I didn't worry too much about it. The combine did good, moving along between 2.4 and 2.8 mph. Some spots where the corn was better, it didn't really give me fits. nothing growled, nothing choked, no bog downs.

Now, I moved over to the next farm and ran down about 8 acres of 193 bushel corn. again, nothing is growling, choking, bogging down. But, I haven't pushed it over 2.4 mph, because the harvesttrack needle jumps up. I don't see corn on the ground behidn the machine, and walking along side while it is running, it looks like dry ear tips hitting the sensors, not corn kernels. What I did notice was that the rock trap was completely stuffed with unshelled ears, husks, cracked corn, and cleaned cobs.

I cleaned it out, and haven't had a chance to run it to check it again, because Im waiting on a part. I read through the manual and it says nothign in teh trouble shooting about the rock trap filling like that. I noticed hardly a single kernel of corn on teh ground behind the machine, but, laying on the back axle is lots of starch powder and cracked corn mixed into the chaff. I would assume it is overthreshing, but my cylinder speed is at 320 right now, and the concave is set 1 notch from teh widest for corn. when I slowed the cylinder down more, I got kernels on cobs coming out the back. I'm afraid to open the concave any more. maybe I should. some of teh ears are like baseball bats.

In my harvest bliss, I completely forgot to check tailings, but, I guess the cracked corn could be from excessive tailings.

Since I am not familiar with this blessed beast, I have to ask an obvious and dumb question...

where is the sieve? where is the sieve adjustment?

I'm am familiar with combines that have a chaffer and a sieve. the chaffer is on top. there is a lever for that. the sieve is under. there is a lever for that. on this combine, and in the manual, it mentions a sieve, but, does not say where the adjustment lever is. if I look through the chaffer I can't see teh sieve. there are 2 blue handles on the back. both operate the chaffer. I think I should be opening the sieve to allow more grain into the clean grain auger, and closing the chaffer some to keep the cob tips out of the bin.

I'm just confused, maybe because of teh john deere terminology. maybe they call both sieve and chaffer a chaffer... I don't know...


All I know is that I could possibly have 200 bushel corn and I am pulverizing 7 or more bushels per acre in cracked corn blowing out the back.


Any insight would be great. All in all, I do like this machine. In july I ran a Gleaner K. Now I am running a 6620 sidehill titan II. It's like another world.

Thanks in advance
 
John lets answer a few of your questions here.

1) The rock trap has nothing to do with over/under shelling of corn. It will be full of ears in the first 5 seconds you go down a row. The rock trap is for when you are harvesting small grain crops. When you are running small grains the rock trap will not fill up like this.

2) The top adjustable screen/chaffer. It has two handles because the front is set with one handle. This controls what falls on the bottom screen/sieve. The other handle is for the rear foot of the chaffer. This controls how much of the grain/trash drops straight down into the tailing auger.

3) You adjust the sieve by opening the door under the back of the chaffer(#21 in the picture) you pull the two spring loaded latch handles toward the center of the combine (#20) The door will hing down so you can reach in and adjust the bottom sieve.

4) In 200 bushel corn with a six row head on a JD 6620 you are really maxing out the combine's thrashing capacity. Usually you maybe right around 2 MPH maybe a little faster in low moisture corn and a little under in high moisture corn.

Now to set your combine for maximum capacity in corn. Forget what the setting say are the minimum and maximum. They are just a starting point.

Have the combine full. Do a power shut down. 1) stop the forward motion with the hydro. 2) Pull the kill knob out and kill the engine while the separator is still engaged. Do this quickly. You want the combine separator to stop as fast as you can get it too. Then disengage the separator. Restart the engine an let it cool down
then shut it off. You will not plug the machine up doing this. This will allow you to see where and what the corn is doing in the machine.

1) Check to see if you have whole corn cobs on the straw walkers (there is door right behind the grain bin on the top of the tail housing) If they are split then open up the concave until you are getting 80-90% whole cobs. The indicator on the concave adjusting linkage may not have been zeroed out so I rarely use it for anything but a starting point. You need whole cobs not split or broken cobs.

2) Now with whole cobs you need to slow the cylinder down until you start to see corn left on the cob. Then just speed the cylinder back up a little until the cobs are clean and whole. I usually just run a little ways down the rows. stop for just a minute then back up to where you can see the cobs that drop off the chaffer in front of the header. This allows you to get it close without getting in and out of the combine so much.

Now we need to set the chaffer.

1) I usually start with the front about 3/8-1/2 inch open. The back section about a 1/4 inch wider.

2) Set the bottom sieve at about 5/16-3/8 to start.

Run the combine until you have the separator full. Do another power shut down. (I am only telling how to do this as you are very new to the machine. after you run it awhile you will not have to do this)

By doing the power shut down you will be able to look on the top of the chaffer and sieve an see where the corn/cobs/trash is. So if there is still a lot of corn to the back of the chaffer then you need to open it up just a little so it falls through more toward the front. If the sieve is full of corn then it needs opened up a little so you are not returning as much. If the sieve is full of too much trash/cobs then close the top chaffer a little.

After you have set it then run the machine. You can check the tailings by opening the small door in the cab under your left heal. If it is running clear full then you will need to adjust on the chaffer or sieve some more. If it is mostly corn then open the sieve some more. If it is cobs and trash then close the chaffer some. After you have done it a few time it will become easy for you.

I have not mentioned the fan speed. In corn you usually run the fan wide open or as fast as it will go. You would have to be in real low test weight corn to blow any out. You do need a lot of air flow to separate 200 bushel corn. In wheat/oats/soybeans you may have to reduce the fan speed but usually only in oats will you have to lower it very much.

The fines you see on the back axle are normal. If you get the machine set correctly, like I have talked about, you will minimize them but even 1% loss in 200 bushel corn is two bushel per acre.

When you get the machine separating like you want and the loses are where you are happy. Then you can set the Harvest track monitor. Have the selector set to monitor both the chaffer and walkers, combined. Have the seed size knob set to the largest size. Operate the combine at the speed where you have everything set for the losses you want. Then turn the top knob to adjust the needle to be centered in the green on the readout. So when you start to lose more than you have it set for it will show it.

I know this is kind of long. If you have questions email me and we can exchange phone numbers so I can walk you through some of this.

Your cob tops in the bin is more than likely the concave set too close. The cylinder at 320 is kind of on the slow side. Remember the settings can change from one variety to another but you usually will only have to adjust the concave for cob size and the cylinder speed for how hard the corn shells.
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That is one of the best setup explanations I've ever heard. I've had it explained in person before and never understood it that well.
 
I will add that you can get cob tips if your concave is set too WIDE. Look to see if the cobs have scuff marks on them. If they do, the concave is too wide. You want the ears to go through the cylinder in one motion. When the concave is too wide they ears will be "pawed" by the cylinder and not taken through in one motion. This can cause cob breakage, especially tip breakage. And yes, the cylinder speed sounds low to me. Very seldom will you get lower than around 380 on one of these combines. Mike
 
I run a 6620 titan II level land with a 643 and while my corn was not that good this year in past years I have had 200+ bushel corn through it and the setup explanation from JDSeller is awesome follow that to a T! But I will add that as long as the internals of your combine are in good shape you should be able to run significantly faster than that, I have run both yellow cab and titan II 6620's and the titan II's will run circles around a yellow cab in corn. You may have cracking/grinding issues because you arent keeping the cylinder full enough, however if you set it as mentioned at a speed you are comfortable with then by all means keep at it and enjoy!
 
Jd knows his combines, just one more
thing keep the fan intakes clean, JDs are
bad about plugging with trash. Can
change results dramatically
 
Jd Seller,

I am going to call John Deere first thing in the morning and request, not I take that back... I am going to call and DEMAND they include your set up instructions in the next reprint of the manual.


That manual is so vague compared to what you just said. Yes, I completely am new to this combine, so there is a huge learning curve, but, everythin you said makes so much sense. I would be a fool not to do as you say. I will. I got my part and I got it installed.

I started on your instructions before teh rain hit and I was doing 203 bpa on the same field where I was doing 193. that's a huge gain!


AS I go up the hill into the limestone clay, I know the yields are better. when they assesed for teh pipeline, they pegged it at 243 bushels. I think I have that much, but haven't gottne there yet. my bottom land spot checked at 303 bushels. Even if I can hit 250, I'm going to be happy.

I can't thank you enough. when this rain dries off, I will continue on yoru path of awesomeness and I will let you know where I stand. So far, all my assumptions were right, with exceptiong to the sieve. I had to get someone else to pull the lever for me because my forearm would not fit in that tiny gap. I guess I should cut down on teh protien so my arm fits.

There are a set of 5, I think, augers that run from the cylinder back. those augers are worn I assume. they must be grinding up the corn. They look like a total pain in the knee to change out. that is where I am grinding corn.

My tailings is nothing but a few tips and a few whole kernels mixed with a bunch of cracked and ground corn. I bet I'm wasting 10 bushels per acre in cracked corn. I'll have to cope with that for teh year, and tear it down in the winter.


I increased cylinder speed to 400 and opened teh concave by 1/8". that was enough to make the machine give a cleaner sample and reduce some of teh cracked corn. I still need to run it more in my higher yeild stuff. When I move to the next farm will be teh real test. according to the test 17.5 feet samples, that farm is making 265 bushels. that will be the real test.


I can't thank you enough. with such a great year, I just hope I can get this thing tuned in good enough to reap all that I sowed.

To all others who replied, thank you so much. this will be the year I can afford to boost the lime and organic content on my home farm up to a level that is tolerable. running down 100 bushel corn just is not fun. It made me sick. I am going to use the money to better it all. I have lime and horse manure, and 2 season old round bales to shred all winter. I am going to try to up that place to a level that will compete.

I'll let you know exactly what I end up with. I just hope it will be as good as teh survey!

thank you.

thank you.

thank you!
 
John the shoe augers WILL not grind corn. They fit real loose in the shoe auger trough. They just do what the raddle chain did in your Gleaner. They just move the corn from under the concave. No way for them to grind corn. You are seeing ground corn there from under the concave.

The shoe augers are turning??? I have seen the slip clutch jaws break and the augers not turn then you will grind the heck out of the corn because the cylinder has to throw all of the corn out the top back. Check that out. It is a long shot but I have seen it happen.


I am willing to bet that the cylinder/concave clearance is still set too close. You need to really look at the cobs and see what they look like on top of the straw walkers. Also if the corn is real dry you may need to open up the concave and really push the combine faster to keep it real full. Corn rubbing on corn will shell without damage in a soft kerneled corn. I mean really push the machine. The JD 9000s are real bad about this. Most guys slow down when they see cracking shelling problems. This sometimes is the wrong thing to do. So try opening it up until you have good whole cobs. Even leaving a few kernels on the cob until you really fill up the cylinder. The push it and see if the damage goes down.

I have seen some varieties of corn that shell harder and they will have damaged kernels at the cylinder no matter what you do. Even some times a rotor machine will do it too in those varieties.
 
The 9000 series combines are not bad about grinding corn. Not if they are set right. I own a 9500 and can make corn look like it came out of a hand corn sheller. Mike
 
I did not say they ground corn. I said they needed to be crowded to be kept full to shell some corn. I have seen varieties that where they would leave corn on the cob but you could not set the concave any tighter or they would split the cob. Solution was to go faster and crowd the corn through the concave.

A JD 9000 series is a lot harder to get used to setting than the 20 and 00 series combines. You have to do it step at a time or you will never get them set right.
 
JD Seller,

Once again you are correct. I was going too slow. I upped teh speed to 2.6-2.8 mph and I have 90-95% whole cobs on the walkers. hardly any ground corn, but there is still some. I just can't run it any faster than this. I am on hillsides that are steeper than what teh machine tilts and when I get moving any faster, it starts sliding down the hill or blowing corn off teh back on the bottom side of teh chaffer. So, I am content.


Today I ran 214 bushel corn, with a 59.9 lb test weight. I'm happier than:

Gallager at a farmers market

A witch in a broom factory

An antelope with night vision goggles

Christopher Columbus with speed boats




hahaha love those commercials...


I'm starting tomorrow at 7am, to load out a truck and when the truck gets moving and teh frost isn't too bad, I should be able to have that farm cleaned off before 2pm or 3pm and move on to the next.


I ran one morning when there was very heavy fluffly frost on the corn and teh whole combine filled up like a snowcone. There was water and big snowballs coming out of it until 10am. I won't do that again!
 
I am glad you are starting to understand how to get your machine setup. You will have some grinding with any machine. Plus you will find some varieties do it worse than others. If you are getting over 200 BPA then you are not losing very much.

What is the moisture of the corn??? Usually the dryer the less grinding. I have seen some varieties that you could hardly shell by hand so they would grind even when dry.
 
The "problems" with the 9000 combines is the book. The suggested settings are abysmal. This year I shelled some drought corn making 40 bushels and the combine did a good job without any cracking. You simply can't set these combines by the book. Actually, no combine can be. It is only a starting point, not gospel. If you know how a combine works you will set it by conditions, not by the "suggested settings". Mike
 
moisture was around 16.9-17.4% When I got into my wetter corn, there were less problems.

everything is peachy keen!

I had a lot of drought damaged corn. I still beat the national average, but the fields were spotty. I hit 303 bpa corn in teh same field where I got 1 bpa corn.

everything averaged out nice. Im glad im done! that is all I can say. I had major stress over this crop as the land owner I leased from has teh property for sale I was worried about what would happen if I didn't get teh corn off before the land sold. just being done feels great.

I did make a big mistake, though...


My 70 year old father was getting stiff and sore running grain carts with side augers, not corner augers. I put him at teh helm of the combine and he never once did a spot check. he ran down fifty acres without a single notice to performance. he has no clue how combines work.

while waiting on him for a fill, I walked out and kicked over some chaff and saw a bunch of ears with tons of kernels left on them. I know the moisture was about 3% higher on that part, so I told him to increase cylinder speed, check his work, and continue. needless to say he had no idea what I was talking about, so he just kept running. I have no idea how many bushels I left out there, but I'd say it was over a 1000. That's like leaving $7000 in cash to blow in teh breeze and scatter over the farm. YOY! I'm mildly depressed over that.

otherwise, I'm thankful for all the help, and now I know a JD combine very well. I put everything into research and learning and it will benefit me now that I have teh experience. I can't thank you enough.
 

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