CIH 1660 rotor and fan speeds

Trying to sort this out so I can call off the service guy. Got my head on straight about how the controls work and, while the weather stinks, it mostly is not raining. Here is how it went.

Combine started right up and the rotor/fan toggle turned it on just fine. At full RPM I turned the dials on the overhead console all the way to the left to get them out of the equation. Used the rocker switch on my right to increase rotor speed. It SLOWLY increased in speed 10 rpm at a time until it got up around 1000 and then I stopped as that seemed very high. Tried the rocker to slow it down and it gradually slowed it down to about 860 and then stopped responding.

I then tried to adjust the fan speed in the same manner but it was completely unresponsive to the rocker switch in either faster or slower.

This is how I understand these work from the manual and forum responses. Am I not understanding something or are these switches malfunctioning? I have not had time to address the ground yet but will look at it this weekend.

The rotor speed does adjust slow, that way it's easier to fine tune in the field. Chances are the threads on the rotor speed adjuster are full of old grease and dirt. Spray the chain and adjuster threads down with penetrating oil and work the rotor speed up and down a bunch of times. The fan adjuster is probably just stuck against the stop nuts. Take the arms off the trunnion and screw the trunnion back and forth on the adjusting screw to clean the threads.

Well now, there's the problem dontcha know? I got no parts book and no service manual. Give me those two things and I'll fix anything in time. Without em I am blind and gets frustrated. Plus, don't buy into that "beautiful peninsula" spiel, the weather here in August is filthy. Tell me where the rotor speed adjuster is located and I will clean it as instructed. Tell me where t'other is also and I will do my best with that also.

Brother, you could drink the air here tonight. Grass is still wet from a rain two days back. Bleah.

Open the door between the engine and the grain tank, inside is the rotor drive compartment. The rotor sheave is the big one in the middle, by the grain tank. It's driven by the big sheave on the right side of the combine. On the front of this sheave is a sprocket that is connected by a chain to an electric motor. That motor is what is controlled by your rotor speed rocker switch. It controls the speed by changing the diameter of the sheave via the chain. The bottom sprocket turns on threads, and moves forward and backward, depending on which way it turns. This lets the front half of the sheave move, in effect changing the effective diameter. This changes your rotor speed. Those threads are probably dirty, not letting the sprocket move it's full travel.
The cleaning fan works in kinda the same way. Standing on the ground on the right side of the combine, find the cleaning fan. There should be a shield made partially of expanded metal. Behind this is the cleaning fan drive. It's a v-belt about 1 1/2" wide. On the top sheave is an arm on the very outside. One end is connected to a horizontal screw that is driven by another electric motor. This motor is controlled by your cleaning fan rocker switch. There's two sets of jam nuts on that horizontal screw. Between them, connected to that arm is a threaded trunnion. Is this trunnion run up tight against the jam nuts? If it is, the motor may not have enough torque to back it off.

dkattau explained it perfectly and since you say rotor speed won't go down I also think dirty threads are the problem. Degreaser and a wire brush will help immensely. I also think the fan adjuster I jammed up to the stop nuts

The cleaning fan drive is on the right side of the combine right inside of the rear of the drive wheel. The top pulley drives the lower pulley that is connected to the fan. The top pulley is adjusted in and out with a small electric motor to to change speed when you push the rocker switch inside the cab.

Now walk back ten feet just ahead of the rear axle. Look up between the engine and the cleaning area of the combine. You will see a sprocket with a chain on it in front of a big pulley with a drive shaft attached to it.

That sprocket with the chain and electric motor is what adjust the rotor speed.

Leave the combine idle throw the separator in gear.

Stand clear of the machine and have someone run the rocker switches up and down to see if the small motors turn the pulleys in and out.

Simple to see if you have someone to run controls while you watch.

Gary

That is excellent, thanks. I have questions now that I have done this. Have a look at the top of the thread if you could.

Thanks much for the two excellent descriptions. Took me right to the parts in question. Here is what I have going on:

1) Fan control does not work at all. First thing I checked was the plug on the motor and one wire lead is pulled out of it's connector. This motor has a broken circuit. I will repair that and see how things go.

2) I observed the rotor speed in operation while the dottir ran the controls for me. I was safely out of reach. After having been worked a few times the motor and chain/sprocket went from intermittent operation to constantly turning when the switch is held down. Now the questions.

First, how fast should the motor turn the sprockets? This is working VERY slowly. It adjusts RPM by 10 about every 5-10 seconds. There are no visible threads to clean. Everything is inside housings it would appear.

Second, when operating the speed control I am seeing periodic sparking. This is in the area where the drive shaft connects to the large sprocket. I cannot get close enough obviously to see exactly where the spark is coming from. Looks like motor connection is on the other side and higher so not likely coming from there. I will look for something shorting with the combine off but was hoping you might have some idea.

That is is. Been a great help getting in there and looking at it like this.

The thread to clean will appear when you adjust the rotor speed up. They're on the shaft where the sprocket is. Only about 6-8 threads will show. Clean with some degreaser and a wire brush. That sprocket does turn slow but steady but rotor speed should increase a little faster than what you're seeing. Cleaning the threads should help. Not sure about the sparking