KX-080-4 KUBOTA Excavator

Good Afternoon,
I recently purchased a Kubota KX-080-4 (note the #4) excavator, brand spanking new. Been using it for 3 months now and from day one realized that this machine TIPS OVER upon less than normal use. Holding a 42" bucket EMPTY, the machine tips over when fully extended.
This is on a flat surface.
Machine is JUST capable of handling a 2 foot bucket (filled) at full reach over the side.
There is a hydraulic thumb and quick coupler installed on the machine.

This model KX080-4 is relatively new model.

Is anyone else aware of any stability issues with the (-4) model. We know people who own a KX-080-3 that have no problems.
Anyone own one of these that is experiencing the same problem?

Our dealer is suggested we buy counter weights. So we did, purchased extra counterweights and problem still exists. We are currently waiting for Kubota rep to contact us to discuss issue with them, we were just reaching out to see if anyone else is experiencing similar issue.

Thanks,
beats-a-shovel

Something sounds very wrong. I have a 057-4 with no such issues, a friend has a 080-4 and I had no problem swinging the mower 360 and even bouncing it at full reach over the side.

Yeah sounds very weird. My u50-3 is very stable

Good day
We have seen similar complaints with excavators, from what we can see with the Kuboto is that the maximum load across carriage is 1500 Lbs. (worst case scenario cross carriage)
Suggest that you check the weight of the attachments since the 1500 Lbs to that at the arm end
(Without bucket).
Establish the weight of the bucket plus the attachment subtract this from the given figure.
A 48” bucket is not small for a machine of this size, we would recommend you establish the volume.
Using a 75% fill factor would not be unrealistic to this you need to estimate the weight of the material you are excavating.
Example clay like material can weigh in heavy where as at the other end of the spectrum coal is extremely light.
If we can be help please come back and we will try to assist.
Kind regards
Uffex

Machine stability

Good day
Found this in our archives may be helpful
KR
Uffex

View attachment GI Bucket size SE2010341.pdf

My 57 handles a 36" fine. I can mow over the side at full reach with a 700lb mower in a 15* cross slope and be fine with finesse.

Thank you, everyone for your replies.

We know people with a KX080-3 that does not have this trouble. I am unclear how many people actually have the quick coupler and the hydraulic thumb attached.

Uffex, I understand exactly what you are saying, the pdf file was helpful also. We understand about adding the attachments effects the weight at the end. We will have to do some calculating to see what the machine will comfortably handle. Guess we were just thinking that the machine was capable of handling the attachments that are made for it. If this is actually the problem (that it tips because we added the attachments), then I would have hoped Kubota/dealer would have specs showing what the machine is capable of having added attachments to it, and which attachments are okay to add. If the machine cannot handle the attachments made for, then to me that is a design flaw.
Our dealer even sold us CLASS 5 buckets (which makes the problem ALOT worse).

We own excavator KX-121 and have all same attachments on that machine with no problem. Although the 121 has no tail swing.

Still waiting on a Kubota rep to contact us to discuss this problem.
Just found out the dealer is currently making MORE counter weights for the machine.

I'll update when the rep talks with us.

Thanks,
Beats-a-shovel

Does friends machine have a quick coupler/hydraulic thumb attached also?

lumberjack said:

Something sounds very wrong. I have a 057-4 with no such issues, a friend has a 080-4 and I had no problem swinging the mower 360 and even bouncing it at full reach over the side.

Click to expand...

Does friends machine have a quick coupler/hydraulic thumb attached?

Yessir, both of our machines have the quick coupler and thumb. I also have Kubota's 36" bucket for my 57 with no issues (assuming smooth operation). I also have a ~700lb grapple saw with a hanger that gives me a little more reach. I know the 57 and 80 are different machines.

Is it possible for you to video the issue? Empty bucket, full reach, start with it on the ground and try to slowly lift it. Obviously quick/jerky motions will get the tracks off the ground.

Hopefully your trip to Marshall's will be enlightening. Let us know how that goes.

I ran a Cat 308E2 for a week a while back, QC, pro-link thumb, 36" digging bucket, NO counter weight ointhead That was a ride, it was tippy at full reach with a empty bucket. I would think it would need a 1,000 lb counter weight to make it better. If I had to guess a QC and a thumb on a 8 ton machine probably adds 500lbs or more?

Is it the Kubota style coupler or a pin grabber coupler and is it the Kubota thumb?

Werk Brau.

What kind of quick couple is on it?

I have a 080-3 with factory quick coupler (one pin to remove to take bucket off) factory thumb 36" tooth bucket. Can feel a little light in the rear with full bucket over the side.

From what I understand, it's a Werk Brau coupler and thumb.

Canadian_digger said:

What kind of quick couple is on it?

I have a 080-3 with factory quick coupler (one pin to remove to take bucket off) factory thumb 36" tooth bucket. Can feel a little light in the rear with full bucket over the side.

Click to expand...

Yes, it is a Werk Brau coupler and thumb.
Sorry we didn't reply sooner, out of town on vacation.
We visited a Kubota dealer to test run one of their KX-080-4 and seem to see the same results. The dealer was very helpful (even though we did not purchase our machine there) From what we can gather, the CLASS 5 Werk Brau buckets that were sold to us (with new machine from our dealer) were most likely custom made to fit the KX-080 machine because these are generally for a larger machine. That, along with the thumb and quick coupler adds about 500+ lbs extra to the end of the boom, with an empty bucket. It is thought that this is just enough to cause the machine to tip.
The dealer we bought it from has apparently talked to Kubota and adding weights to the machine is our dealers resolution. It already has the additional weights Kubota sells, and now they are custom making MORE weights for it. Unsure who will pay for all this, our dealer never should have recommended Class 5 buckets for this machine, and you rely on a dealer to know what attachments a machine is capable of using.
If we changed back to class 4 buckets, that would require a new quick coupler, etc too. As of now, we are waiting for the additional counter weights.
Unfortunately, we think they are about 4 inches thick and will interfere with the raising of the blade. Ugh.
Oh, and the rubber tracks we have on come in to play also, because the sides have a little give were a metal tracks would provide more stability.

Thank you all for trying to assist us. We know people with KX-080-3 machines with all the same attachments but class 4 buckets, so it has to be them Class 5 buckets are just too much extra weight.

Take care, and we will update this once again to let you all know how the extra weights work out........we don't think 1000lb will be enough.
We LOVE our KUBOTA's and would hate to switch.