6600 Concave Question

Every since I have had this combine, I can't get as clean a sample in the grain tank as I could with the old MF 750. I cut a sample of rye last Saturday afternoon(TOO wet!!). The straw on the ground looked good, only found 1 rye seed in the head, couldn't see any on the ground, but there was some seeds laying on the rear axle. Looked in the grain tank, several whole stems and heads, lots of heads in there also. I had the concave set on 2 and the cylinder about 950 or so. Too wet to try to adjust and cut some more.
I took the inspection door off at the front of the straw walkers to look inside for any large holes, everything looked good. BUT, how wide should the openings in the concave be? They looked awful wide compared to what I remember from the 750. I couldn't reach far enough to measure, so I stuck bolts into the opening to get an idea how wide they are. A 5/8's bolts is loose and a 3/4 is too big, so I'm guessing the openings in the concave are about 11/16" wide. The previous owner only ran corn, could this concave be a special one for corn?? How wide should the openings in the concave be? If it ever dries enough to go, I'm gonna close the concave till it rubs and the open it a little and speed up the cylinder. Just curious about the size the openings in the concave should be. Chris

I'm going to catch it for this, but:

I've never known a modern Deere to give as clean of a sample as an older Massey. I've had a JD 9500 for a long time and it just doesn't do the same job as our old Massey did.

Just my experience.

A guy around here has a 6600 and the corn is very trashy, lot of cob pieces and shucks. Not sure of the answer for ya though

It can be done on a 9000 series combine but don't use the suggested settings. They are terrible. I have a 9500 and it will sterilize grain and get all that can be gotten. Not knowing how to set them is the chief cause of loss, not some inherent design flaw. Mike

Your operator's manual has a detailed explanation of how to proportion the concave to the cylinder. Every cylinder combine should have this done on a regular basis. If this adjustment is not correct everything else you do to adjust the combine is only a band-aid. This is probably the most important adjustment to have right on the whole combine. Do yourself a favor and look at your book (if you don't have one, get one soon) and do this job right. Anything else is just spinning your wheels. Mike

I've got a late 9400 and when I'm running 6row narrow thru good to excellent corn it's perfect no trash in the tank and the only shell corn on the ground is whatever shells at the head. I've got some steeper sidehills so I only move 3-3.5 mph. Flat bottom ground I go a little faster. But when I get into thinner ground or doing a massive amount of point rows turning all the time the sample gets a few small pieces of cob, nothing to worry about. I figure it's due to the machine running empty on the turns or not getting full in the thinner soils. I could tell it a little more with the 4420 turning on the end I would get a few kernals thru the return. Just an observation of mine.

OK, I read the manual, The throat needs to come off to check for level and then measure where the rasp bar meets the second bar on the concave. With all the overtime at work right now and the 5 acres of rye for seed about ready to cut, It doesn't look good for that happening right now. I have a shaft tachometer, I will check the countershaft rpm and make sure that it is correct. BUT, the main question of the post was, what is the standard opening of the concave for a 6600, Just curious. Thanks, Chris

I don't believe you need to remove the feederhouse to proportion the concave. You can drop the bottom door for the stone trap to check the front and go through the inspection doors for the rear adjustment. Your manual will tell you the rest. Mike

Like mike says lift up your header , put your header lock in place, crawl under there and open the doors there to look at your cyl, there is a door that fold's down, and another half door that goes up, But if its wet no combine will give u a clean sample .The back of the concave can almost be rubbing on the cylinder.Another thing is to lay a straight edge along the width of the concave, If u see a lot of daylight in the middle it needs replacing or sharpening.