7720 2spd cylinder drive

Im wondering what would all be involved in putting a 2 speed cylinder drive on a pre titan2. I plugged cylinder a couple times in corn running at 350rpm and for what belts cost id like to convert it and not have the constant thought of am I pushing too hard. Ive rebuilt the majority of the machine so im not looking to trade and start rebuilding all over. great machine with almost all the titan 2 options except 2 speed cylinder. as a side note im hoping to build a electric fan speed adjustable from the cab this year also. any body have one and some pics? air design (airdesign.org) used to make a kit like this. also have any of you guys ever put a draper on one of these and how did it work? thanks for the help and input in advance.

If your belt is slipping at the 350 RPM setting it needs replaced. The drive is a Posi-Torq drive which tightens the belt if it slips. If yours still slips it is stretched and/or worn and needs replaced. While the project could be done it would be a sizeable undertaking. Different cylinder shaft, pulleys, etc. I used to own a 7720 similar to yours and had no trouble at the slow cylinder setting IF you kept the belt in good shape. Mike

(quoted from post at 20:16:08 01/23/15) Im wondering what would all be involved in putting a 2 speed cylinder drive on a pre titan2. I plugged cylinder a couple times in corn running at 350rpm and for what belts cost id like to convert it and not have the constant thought of am I pushing too hard. Ive rebuilt the majority of the machine so im not looking to trade and start rebuilding all over. great machine with almost all the titan 2 options except 2 speed cylinder. as a side note im hoping to build a electric fan speed adjustable from the cab this year also. any body have one and some pics? air design (airdesign.org) used to make a kit like this. also have any of you guys ever put a draper on one of these and how did it work? thanks for the help and input in advance.

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Putting a two speed on won't help
Put new belts on and you will never slug cylinder in corn
Belts would be cheaper too

thanks for the replies sounds like a new belt is in order instead.

Does anyone have in cab cleaning fan adjustment on their deere xx20 combine that could share a pic of how it works. ive seen combines with them but never close enough to see the kit. air design no longer builds them but im going to contact them beginning of the week to see if they would share some blue prints or photos.

I am wondering why you want a electric cleaning fan adjustment????

In corn and soybeans you run the air WIDE open all of the time. The only time I ever have set them lower is in small grains like oats or wheat. Even then it was set once and not fooled with until the next crop.

As for a pickup header on it they will work well. You have a lot of capacity.

If you want more/better cleaning out of your JD 7720 then change the concave and cylinder bars. The 15 bar concave is the earlier JD 7720s was replaced with a 13 bar one in the Titian IIs that really helped out on the thrashing capacity in them. You will need to change the beater grate as well. I always liked Ausherman bars over JD and Tempe cylinder bars.

If your having chaffer air flow issues than check and makes sure your hub is not worn where the speed adjustment pushes against the viable sheave. That sheave has a small chafer that hold the bearing away from the hub about .200. If the bearing has ever when bad it will eat that chafer off. It is easy to tell. The belt should be clear out to the top of the sheave when it is adjusted as fast as it will go. If the belt is down even a little bit then replace the belt and check it out again. IF it is still not clear up than replace the outer sheave and bearing.

If your are truly getting full fan speed and still need more flow to float the chaff off the top chaffer then look up an Air foil chaffer. They work Great I only use them any more if I have to replace and chaffer.

not having cleaning problems or fan speed issues would just like the adjustment in the cab where the tach is. have updated concave and bars and air foil chaffer. im in sw nd so small grains are more prevelant than corn. ive got a pickup head, but the draper I was wondering about would be like a 972 mac don or honeybee 25 footer. neighbors all run drapers on newer machines and they really feed nice not so sluggy in short wheat. guess im just trying to modernize some convienence comforts into it. I like the machine does a great job, just want some creature comforts the newer machines come with, without buying a newer machine and starting the rebuild process over on the rest of the machine.

Call around to the combine salvage yards. I would bet that they would have one on a salvage machine. The electric fan speed adjust was a common kit when these combines were newer.