920 MOCO issue

[K Effective]

So, the forecast of five straight nice days encouraged me to hook up the new-to-me JD 920 rotary mower conditioner I bought last Fall and cut a couple of acres. One field away from the road is quite thick grass with alfalfa and clover, a nice mix. Ground is still a little damp underneath, but timing is everything. I definitely struggled with the geometry making turns- the mower sticks out farther away from the tractor than my 1219 sickle bar mower did. It will mow faster it seems, but I was surprised that my JD 5400 struggled to make enough power for it, at least it felt like it was working hard.
The question is, when I tedded the windrows to spread them out to dry, I noticed a skipped strip on either side of the windrow. Almost like it was a sickle-bar that had a loose or missing tooth. But this is rotary, and the blades were turned to a fresh side just now. Everything looks to overlap when I turn it by hand, any thoughts or experiences?

Oh yeah, as expected, when I came in last night, the late weather guesser said we had rain on its way for today/tonight, a storm they though would clearly miss us turned right toward us, as soon as I started cutting. Figures.

 

[pms]

Sounds like you already checked for foreign objects on cutterbar.If the"ends" of the knives are worn down that can happen.Wear plates between discs need to be clean or if
worn then replaced.Also very light hay will leave strips.If conditioning is too aggressive that can happen assuming its a flail conditioner.Platform weight can be a
factor or going to fast or a combination of these issues.To me it almost sounds like you might be going to fast and not have enough tractor.

Paul

 

[M Nut]

About 90+ hp to run that mower effectively.........I'm betting just not enough power for the machine.

 

[K Effective]

thanks for the reply, paul. I started out in my lowest gear and worked my way up from there as I became more familiar with the machine. It started streaking right away, regardless of speed. It wasn't until I got into the B range that it seemed to be working hard. Even my wife said it looked fast, but that may be the first time she has ever paid any attention, so I didn't take much from that.

The blades are square on the ends, only worn a little on the backside. From the looks of it, the blades overlap by 4-6 inches as they turn, I can't see how the hay is not getting cut. It looks like a zero-turn deck where the front bogie wheels make two small strips in the grass before the blades can cut it, but there are no wheels in front of this mower, nothing under the hood at all. I will know more if and when I can bale the hay off, or at lest get it dry enough to rake. expect that to be two weeks or so...

 

[K Effective]

About 90+ hp to run that mower effectively.........I'm betting just not enough power for the machine.

WOW, really? Just not turning the rotors fast enough? Why does it not streak between every rotor, just looks like two spots.

It'd be a shame if I had to buy a bigger tractor :wink:

 

[JD Seller]

A JD 5400 will NEVER run a JD 920 effectively. You need to keep up PTO speed and ground speed. The streaking your seeing is caused by slow cutter speed and too slow of ground speed. You need to crowd the hay back against the cutter bar and it will mow much better.

I personally owned a JD 920 for years. It would make my JD 4020 bark and the JD 4430 to run it right in good thick hay. A JD 5400 is only 60-65 PTo horse power. That is 30-40 too light.

 

[K Effective]

Seems to be a common idea here, the auction where I bought this only featured a 2355 and 2840. I figured I could make it spin, just slow down the ground speed and have it mow just as well, but I guess I was wrong.

I'll continue to play around with it, but I cannot imagine uprating tractors. Then I'd have to think about a round baler, and next thing you know, I won't be able to throw 3000 bales a summer all by myself. How can I ever hope to maintain only 40% body fat without all the extra workouts? I'll blow up like a tick on a hound dog, get sloppy fat.

 

[K Effective]

I was going through the manual to see about adjusting the mower, and came upon an interesting problem. I had noticed that one of the windrow-narrowing panels had come in contact with the tire when I was mowing. Seemed odd. Someone has put 12.5L-15 tires and rims on this machine that calls for 9.5L-14s. They looked kinda big all along, but I never looked it up. it appears to me that much taller tires will screw up the geometry of the cutter bar, actually flattening it out if I am doing my math right. One of the suggestions for fixing the poor cut is to make that cut angle steeper. I will look to put the normal sized tires on it, as well as try to increase my ground speed as I cut more this year. A buddy has offered a 4020 to test cut with, it would be about 30 mile drive, but the price is right.