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Discussion Starter #1
So we were harvesting 2 different varieties of wheat on and off the whole season with a s780 combine. We never had any problems in 80 bushel wheat with losses or tailings getting full and I had a premium sample. But we changed variety’s 3/4 through harvest to a wheat that only has 15 inches of straw and has really small heads but there are TONS of them. Just looking at it from the combine you’d think it’s just 20 bushel wheat but then you glance at the yield monitor it’s making 90 and you think “how?” But in this wheat I have high sieve losses if I go over 3mph. I can’t raise the fan speed to clean it up because it fills my tailings and blows wheat out. I have to open the chaffer to reduce loss and open the sieve to keep tailings down. Resulting in a very dirty sample. You guys got any tips for this wheat? Like I said it’s just this variety. In the other 2 I was doing really good.

Setting Ranges I would use. rotor-750-900, concave-8-12, chaffer-12-19,sieve-8-12,fan-950-1200.
 

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Is there whitecaps and unthreshed heads in the return or just wheat? If you are not threshing all the material, try filler plates on the front concave or a concave with small enough holes that just a wheat kernel can fall through.
 

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Discussion Starter #4
No I’m getting it threshed. I’d say the concave and rotor is set perfect because the heads are still intact but there isn’t any grain in them and I have no rotor loss. When tighten the concave I break straw up and really overload the shoe. But there is free grain and chaff in the return. And somehow more fan makes it worse which completely the opposite of what happens in the other varieties. I think this variety just completely overloads the shoe with the head material because there is so many heads.
 

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Try to open the sieve and Chaffer up and increase the wind. It will be a higher volume of air at lower speed and hopefully ride it out the back. Closing the chaffer and sieve will only reduce wind flow. If that works you could then try closing the sieve slightly to clean up the sample.
 

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I think someone should build separator grate clip on covers that have elongated holes in them that would tend to let small seeds through but not thrashed heads or pods to reduce this problem.

It’s a separation problem, not a thrashing problem, not a cleaning problem. Claas solves this with their separator covers, Gleaner solves this with an air blast under their separation acceleration rollers combined with a short wide chaffer and sieve.

The good thing at least is, you aren’t hitting this wall until the bushes per hour limit is quite high.
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Try to open the sieve and Chaffer up and increase the wind. It will be a higher volume of air at lower speed and hopefully ride it out the back. Closing the chaffer and sieve will only reduce wind flow. If that works you could then try closing the sieve slightly to clean up the sample.
Sounds like you have covered all the bases. I would agree with this post as it is about the only thing you have left. Unless you tried an airfoil top sieve?? Their strength is blowing the air more straight up which seems like it would lift more of your chaff and allow the wheat to fall through. It is hard for me to imagine not having a bottom sieve, but it would allow a lot more air to get to the top sieve, and at some point if you have enough air on the top sieve, all the material other than threshed grain should blow out. ?? Just saying. I know some IH rotaries in the past did not have enough space between the sieves at the front which severely restricted the necessary amount of air getting to the chaffer, which created matting of grain and chaff on the chaffer due to not enough lift, which let too much chaff sluff through to the bottom sieve, which then needed to be too closed to prevent a dirty sample, which further restricted airflow to the chaffer ... Seems like more air blowing more straight up is a goal??? If it is just one field maybe just go slower. It is the 10th of July!
 

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What are the conditions like,Temp,grain moisture,easy threshing? You said you don't have rotor loss and all the heads are threshed out,if this is a variable stream rotor have you tried setting the rotor vanes in the advanced position so that the straw spends even less time in the machine and gets less time to be super broken up and load up the chaffer? I would also as stated above open up sive and chaffer and increase wind.When we harvest heavy bushel weight wheat on irrigation i run my fan at 1350 with chaffer and sieve more open.If you are loading up the machine lots open with no unthreshed heads open up concave more. IF YOU HAVE NOT YET, REMOVE FRONT CHAFFER EXTENSION FOR SMALL GRAINS ON 80 AND 90 MACHINES!

Make sure your concave and shoe setting are calibrated and reading accurate values. Mabey this is a variety where it makes a bigger difference and is noticeable when these setting are not calibrated dead on.
 

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What are the conditions like,Temp,grain moisture,easy threshing? You said you don't have rotor loss and all the heads are threshed out,if this is a variable stream rotor have you tried setting the rotor vanes in the advanced position so that the straw spends even less time in the machine and gets less time to be super broken up and load up the chaffer? I would also as stated above open up sive and chaffer and increase wind.When we harvest heavy bushel weight wheat on irrigation i run my fan at 1350 with chaffer and sieve more open.If you are loading up the machine lots open with no unthreshed heads open up concave more. IF YOU HAVE NOT YET, REMOVE FRONT CHAFFER EXTENSION FOR SMALL GRAINS ON 80 AND 90 MACHINES!
everything s6704940 says , the only time I have this problem was with frozen light wheat that was popcorn dry. Did you try a round bar concave on back.It worked on short barley losses the grain before the straw is too mangled. A real fix is sunnybrook
 

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Discussion Starter #11
Thanks for all the tips. So where to start! The conditions are tough. Very humid, grain is about 12% moisture. Warm 90 degrees. I do not have the variable stream rotor because I do harvest corn, beans, etc. I’m running those XPR concaves and have the first concave covered with cover plates. These things are awesome especially in tough threshing conditions. It’s why my rotor loss is none. There is very little straw coming off the shoe so I’m not breaking it up. I think I may need some of those separator covers to help the shoe load. The weird thing is I’ll open chaffer to 19 sieve to 15 and I’ll watch loss and tailing go down but it’s really dirty. So then I’ll speed up fan to 1250-1350 and I’ll watch loss and tailings go up again. Do I need to open more? I’m gonna get a good sieve measurement the next time I can so I can see if they match what the display says.

I have not removed front chaffer extension. Do I need it for corn? We only have 200-300 acres per year of irrigated corn that can go 220-290 typically and our Dryland is low yielding so 80-120. But we are bringing in 16 rows of 30 inch corn.

I would love to get an airfoil chaffer. Can it be used in the corn yields that I mentioned? Thanks for the replies.
 

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Now that you mention you are running XPR concaves that is why you have no rotor loss,but WOW I bet those things are overloading the shoe to a point where it is hard to seperate.Yes the front chaffer extension is needed in coarse high yield crops like corn.I don't think they work well with very high chaff loads witch i would think the XPR's are giving you.
 

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Have you verified the sieve losses are actually there on the ground?

Is there small grain blowing out?

I haven’t actually read the other posts, maybe this has been covered already.
 

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Discussion Starter #14
Yeah you would think the chaff load would be high. But why am I not overloading it in my other varieties??? This is what I don’t understand. If I was fighting the machine all summer because of the concaves I would’ve pulled them and tried the small wires again.

I know it’s coming off the sieves because I’ll stop, get out, and look underneath where the sieve loss sensors are. And there is literally a pile of grain there if I go over 3 mph. Checked it going 2.8 mph and loss was very low.

We didn’t realize it at the time but we had the same problem last year with the same variety with a 2013 s680. We had the thick volunteer trail right where the combine went. But we thought that was due to the low test wight of 56 because it just had 3 inches of rain before harvest and was a drought stricken crop.
 

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Try a Stall stop to see what’s happening in there. Look for how even the loading is on the sieves. You may have to adjust the deflector plates on the conveyor augers and then use them clip on plates for the grates

Many years of running JD’s taught me that sometimes .5 - 1kmh speed difference can make a huge difference in losses when in less than ideal conditions. It’s just one of them mystery machinery things you have to live with.
 

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Try a Stall stop to see what’s happening in there. Look for how even the loading is on the sieves. You may have to adjust the deflector plates on the conveyor augers and then use them clip on plates for the grates

Many years of running JD’s taught me that sometimes .5 - 1kmh speed difference can make a huge difference in losses when in less than ideal conditions. It’s just one of them mystery machinery things you have to live with.
This was my next thought also. If you have the front concave blanked and you are threshing very well then you have a lot of threshed wheat waiting to drop through the concave when it comes around the second time, possibly overloading the right side of the sieves. And if you are returning lots, this compounds the overload on the right side where the return dumps in. So check if your grain loss is just in a narrow streak off the sieves on the right side. I ran a filler plate under the return just to force the threshed grain to be spread by the sweep of the rotor more over the entire width of the sieves. I am talking red single rotor but getting the balance of that spread correct is pretty important on single rotor machines. I like what I see in the Sunnybrook box concaves in that you can throw in a more open box on the left side of the front concave (as opposed to a full blanking plate)or wherever you are under loading your sieve. Another mod we did on Case machines was to add in aftermarket concave adjuster brackets to be able to adjust the concave left or right to control where that load dropped onto the sieves better. IIRC IH or Case did not originally recommend a wider space on the right and tapering to a pinch point on the left side, which is what we modified to be able to achieve, more in line with conventional threshing logic.
 

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We didn’t realize it at the time but we had the same problem last year with the same variety with a 2013 s680. We had the thick volunteer trail right where the combine went. But we thought that was due to the low test wight of 56 because it just had 3 inches of rain before harvest and was a drought stricken crop.[/QUOTE]

That thick trail might also have come from grain leaking out by the fan, this happens when the front of the shoe is severly overloaded.Some varieties you can thresh with round bar no problem and other not.
 

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We didn’t realize it at the time but we had the same problem last year with the same variety with a 2013 s680. We had the thick volunteer trail right where the combine went. But we thought that was due to the low test wight of 56 because it just had 3 inches of rain before harvest and was a drought stricken crop.
That thick trail might also have come from grain leaking out by the fan, this happens when the front of the shoe is severly overloaded.Some varieties you can thresh with round bar no problem and other not.[/QUOTE]

Is the overload on the right side?
 
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