ZT52HD DECK VIBRATION FIX

[NealS]

I have been wondering? My kubota tractor has a non adjustable idler pulley, set just behind and near the middle of the long air conditioner compressor belt. Since it is non adjustable, I presume it is to keep the belt from slapping back and forth. Do you think it might be possible, the slapping we can see our mower belt doing sometimes, might be causing this rattle, and maybe we could do similar with a back side idler on our mowers long belt?

 

[NealS]

Well, we put an idler pulley on the back side of the long side of the drive belt today. Mounted it to push in on the belt about 1/2".
First impression was it made a world of difference in how quite it was.
We only mowed about 1/2 acre so far and before we were done, I heard a little rattle :frown: at times.
After installing and running at fast idle, the belt would still whip (maybe not as bad) between the idler and the front pulley. At the same time the tension pulley would be jumping a lot. Then we went to full throttle and everything smoothed out. That was without a cutting load of course. I guess time will tell.

Someone else was asking about blades. We ran the factory blades for the first year, then changed to the heavier Oregon G6 Gator Mulching blades. We could tell no difference between the two, other than it mulches better.

 

[cpurvis]

Are all of these ZT52HD's powered by the same engine? If not, is the vibration common to all, or just the Kawasaki?

I had originally scratched off the engine as being a possible cause but what if Kawasaki changed the flywheel slightly?

 

[Woody99]

Are all of these ZT52HD's powered by the same engine? If not, is the vibration common to all, or just the Kawasaki?

I had originally scratched off the engine as being a possible cause but what if Kawasaki changed the flywheel slightly?

Mine has the Kohler motor.

I probably buried my thought to far in my comments, but two times I have been able to make significant reduction in the deck rattling by repositioning two blades. Could a couple of you try it too and see what happens?
I don't know why it would make a difference, but it has. You would think that the installation of the blades would put them in a totally random position relative to each other, but loosening two and moving them a quarter turn really seems to make a difference.

 

[NealS]

Well, we found that we still had the metal to metal noise under some mowing situations. Saw a youtube video where the owner was putting rubber grommets on a bolt head to keep it from touching the left side belt guard. Pulled our belt guard and found the same bolt head had worn the paint off the underside of the belt guard.
We did our fix a little different.
Took a 1" socket and set it in the press. Placed the belt guard (upside down) over the socket with it lined up on the scrubbed paint marks, then put a small socket over the paint marks and proceeded to apply pressure to the small socket until it had formed a raised place in the belt guard, directly over the bolt head it had been hitting.
This seems to have stopped the metal to metal rattle.
First pic, cover is upside down laying next to the bolt that it had been hitting and before our press work. 2nd pic is after press work. 3rd pic is with belt guard installed.

 

[Woody99]

Regarding the bolt head clearance, I'm not sure if mine came from the factory or was modded by the dealer, but I have about 3/8' clearance above the bolt to the guard.
The guard has a nut below it at the mounting points, and then a nut above it to secure it. There are rubber bumpers on the piece where you can step to hold it up too.

 

[NealS]

I think mine is mounted similarly. Possibly the factory upgrade for this problem may have been taller sides on the belt guard. Just thought if someone had this problem and a press, it might be easier to fix than carry back to dealer. Seems like a waste to make a repair by getting and installing a new guard, when it is so simple to fix if you have a press.

I did think later though, it might be better to use larger sockets, so you would not have to be as accurate with the location of the raised area.

 

[my87csx481]

Mine is a Kawasaki.

My belt guards do not interfere with anything but, I completely removed them a long time ago, to rule them out as a source (along all the discharge chute and bracket and hardware).

I strongly suspect that the whipping belt is causing the PTO clutch to rattle against the "drive dog" that holds the stationary portion in place....possibly being the source of my remaining metal clanging noise....but I'm done screwing with mine....so I will not be validating my suspicion. I've spent way too much of my time reverse engineering, and re-engineering something that is either defective designs, or defective manufacturing processes....or both.

I also strongly suspect that the sheaves of all the pulleys are uneven. Squeezing the belts more in some spots, and releasing the belts more in other spots....causing the belts to ride higher and lower in the pulleys....again, I'm done screwing with mine. I did put a dial indicator on my pulleys, and they did have a bit of a wobble to them (.040" being the worst one), BUT it was only on one side of the V, not both sides at the same time.

 

[DRG ZT HD 52]

Well, we put an idler pulley on the back side of the long side of the drive belt today. Mounted it to push in on the belt about 1/2".
First impression was it made a world of difference in how quite it was.
We only mowed about 1/2 acre so far and before we were done, I heard a little rattle :frown: at times.
After installing and running at fast idle, the belt would still whip (maybe not as bad) between the idler and the front pulley. At the same time the tension pulley would be jumping a lot. Then we went to full throttle and everything smoothed out. That was without a cutting load of course. I guess time will tell.

Someone else was asking about blades. We ran the factory blades for the first year, then changed to the heavier Oregon G6 Gator Mulching blades. We could tell no difference between the two, other than it mulches better.

Where did you place the Pulley & where did you get it? a picture would be nice.

 

[handtools]

I feel this is not normal for the deck belts to dance and wobble like they do on this Apex I have. Whoever designed this machine perhaps was not on top of his game. I doubt that these mower makers have top engineers designing these units. Top guys are too expensive. What's really disappointing is that they go ahead and market these mowers the way they are.
And how many consumers will notice? How many will complain? It's a game for them, and they win. Odds are most will not take note. And when the dealer and maker says its normal, what can we as consumers do? My dealer told me they have had no complaints about this belt issue. He's a large dealer, sells many mowers each year.
What would you think if you opened the hood of your new car or truck with 20 miles on it and saw the belt dancing, wobbling like it does on these mower decks? Then, the dealer said that's normal. Just because this is a lawn mower doesn't mean it shouldn't be made to perform properly.
My question is to anyone who is reading this thread to tell us if they know anyone who owns or has owned a Gravely or Ariens for several years with this issue. What has been the history of belt replacement, bearing replacement on the deck with that machine? How many hours on the machine before a belt or bearing failed? This Apex I purchased is a commercial unit. It's made to mow bunches each summer. I live on a acreage and mow a little over an hour each time. Light use for this type of machine. But, I wanted a quality machine. I am very happy with the cut. Lawn looks great after I get done.
I plan on looking at other machines to see if their deck belt dances, and wobbles like these do. The solution could be something as simple as spring tension. If we all would have tried our machines out at home, then told the dealers to fix this issue or I am not interested in this mower....it would have been resolved. Funny when something is paid in full, they don't want to be as helpful anymore.

I've been mowing with my Ariens Apex with the 60" deck for a little over 2 years and 155 hrs. I haven't had a belt, pulley or spindle problem yet. I also have what I consider to be an excessive amount of noise and vibration from the deck, but it mows great!