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Discussion Starter #1
We're in the middle of replacing the concave and rasp bars in our 7720 Titan II for the first time since we've had it. We're using a new Loewen concave and chrome bars purchased through A&I. My question is, with the new bars and concave installed, the bars WILL strike the concave if the adjuster is tightened up too much. I see no way to adjust a "stop" on the concave adjuster to prevent this and the owner's manaul does seem to suggest that there is no stop to prevent the rasp bars from striking the concave. I was curious as to whether this is the way it is with everyone else's 20 series machines or not. I do not recall ever being able to adjust the concave tight enough to hit the bars with the old concave and bars before this. Thanks guys!
 

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Re: 7720 Concave Adjsmnt (Rasp Bars WILL hit conca

I've never done the replacement that you describe, but I would think you need to adjust the concave down with the levelers so that it won't hit when tightened all the way up. The book will give you a minimum clearance spec. I hope this helps.


Mark
 

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Re: 7720 Concave Adjsmnt (Rasp Bars WILL hit conca

Well the thing is there is no leveler on the right front of the concave that I am aware of. The book instructs you to crank the concave up with the adjuster until the right front is 1/4" at the second bar of concave. Then level the left side with the leveling screw to match it. Then level both sides of the rear up to 1/8". The trouble is when I do it this way (crank the concave up to 1/4" on the right side) there is still enough teeth on the worm gear adjuster to allow the concave to be cranked up enough to strike the rasp bars. Is there an adjustment on the worm gear or the right side of the concave that I am missing? Thanks again. I hate to put it back together this way because I'm sure sometime someone will crank it up enough to hit and that would not be pretty I wouldn't think.
 

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Re: 7720 Concave Adjsmnt (Rasp Bars WILL hit conca

There is a stop on the right hand side, on the gauge itself that you can adjust.
 

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Re: 7720 Concave Adjsmnt (Rasp Bars WILL hit conca

The only thing on the right side is the pointer that you can adjust. When you adjust the concave to 1/4" and 1/8" clearance adjust the pointer so it points to 0. There's no stop, you just have to be careful when closing the concave down. This means you have to get out of the combine and look at the gauge to see how close to 0 you are.
 

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Re: 7720 Concave Adjsmnt (Rasp Bars WILL hit conca

The first few times we set our 7720 with new bars we engage the separator at idle with someone outside the machine. We crank the seperator down until it starts to hit. Then we back it off until the ticking stops. After a little use the bars should wear enough so u can set them tight and it wont hit. This is just my two cents but we all know how much money is worth these days....
 

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Re: 7720 Concave Adjsmnt (Rasp Bars WILL hit conca

I talked to dad about this and we set our concave tight in the back and a 1/4 inch in the front to help lessen the amount of barley we throw over the walkers. So the importance of my post above might change a little....
 
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