Sidekick RTV-XG850 backfiring / loss of power

[catalyst]

at 400 hours, that's a lot of usage. So at that kind of hours there comes many, many questions. Was it maintained properly? What kind of maintenance was done? Who did it? Is a failure normal wear, abnormal wear, neglect, abuse, or indeed a defect? The more hours that a unit has on it the more these are questionable items that hold more validity. Think about it this way. Say you're looking at used cars. You find one you want, but it's got 200,000 miles on it. What's that got to do with anything? At 200,000 miles there are a lot more questions than the one up the street that's got 20,000 miles, right?

and that's where the manufacturer's warranty department is. There are a lot of unknowns when they are processing warranty claims. Look at it this way, from their perspective. Some components are not built by Kubota, they are purchased (outsourced). If said component fails within the kubota warranty period, kubota warranty processors have to get paid by the people who make the part(s) which is just about as annoying to deal with as it is for us consumers to have to carry our stuff to the dealer to request warranty repairs. Say an outsourced part fails and kubota is the one administering the warranty on the unit. Kubota warranty processors have to ask (or tell) the manufacturer of the part that the part is defective-and they often have to PROVE the fact, via pictures or what have you, so that they can get paid. If y'all only knew how much money they lose on warranty repairs in a year, you might raise an eyebrow--or maybe not since a lot of folks just don't care, they only see "their" side of things.

400 hours is not a lot a usage. That would be within the normal factory warranty hours. I would not expect an engine failure within that window to be "normal". You are comparing that to a car with 200,000miles on it, but in reality given most car warranties, the apples to apples would be a car with 30,000-36,000 miles on it with an engine failure, and yes - that would be premature.

 

[Siesta Sundance]

400 hours is not a lot a usage. That would be within the normal factory warranty hours. I would not expect an engine failure within that window to be "normal". You are comparing that to a car with 200,000miles on it, but in reality given most car warranties, the apples to apples would be a car with 30,000-36,000 miles on it with an engine failure, and yes - that would be premature.

Agree, 400hours is not much. I think my truck at the 5k mile oil change intervals it clocks about 320hours on average.

 

[Tombstone Ranch]

Speaking of...I've done 3 oil changes now, every time the oil shimmers, but the engine keeps purring, anyone else seen that on the gas engines? Normally I don't like anything like that after the initial break-in.

 

[lugbolt]

400 hours on a unit that gets used in the dirtiest, dustiest possible conditions is about the same as a LOT more hours/miles on a car that runs in a lot cleaner conditions, at 10-25% load most of the time (where anything kubota is typically 50% to 100% load all the time).

all I'm saying on that. Y'all are comparing cars to RTV's which is comparing grapes to steak. Hours is relative. Relative to maintenance and how it's used.

I've had them come in with windowed blocks at 12 hours. And I've seen them run thousands. All depends on the owner, user, and maintainer.

as with all other forums, there are a lot of unknowns. Until the unit is in front of "us", nobody really knows.

the sidekick engine runs around 4000-6000 RPM constantly. Grab your pickup truck and everywhere you go, leave it in low gear so it runs 4000-6000 RPM, and do this in the dust/dirt with a load on it, and see how long it lasts.

 

[Siesta Sundance]

I still agree, 400 hours on maintained machine is not much......

 

[catalyst]

400 hours on a unit that gets used in the dirtiest, dustiest possible conditions is about the same as a LOT more hours/miles on a car that runs in a lot cleaner conditions, at 10-25% load most of the time (where anything kubota is typically 50% to 100% load all the time).

all I'm saying on that. Y'all are comparing cars to RTV's which is comparing grapes to steak. Hours is relative. Relative to maintenance and how it's used.

I've had them come in with windowed blocks at 12 hours. And I've seen them run thousands. All depends on the owner, user, and maintainer.

as with all other forums, there are a lot of unknowns. Until the unit is in front of "us", nobody really knows.

the sidekick engine runs around 4000-6000 RPM constantly. Grab your pickup truck and everywhere you go, leave it in low gear so it runs 4000-6000 RPM, and do this in the dust/dirt with a load on it, and see how long it lasts.

it has never been run hard. it has been babied, which sounds like the reason behind the failure. it looks nearly new. I cited 400 hours, because that was Kubota's documentation for warranty coverage - so Kubota must also consider that to be within premature failure span.

 

[catalyst]

I just wanted to provide an update, as I've finally had some time to sit down with this project again. To be honest, I've been putting it off because I was so upset with how this turned out.

I picked up a new compression tester and finally had time to perform a compression/leakdown test. My values did not match what the dealer reported. As I pulled the plugs, I also noticed a distinct smell of fuel, which I thought to be odd, since they were supposed to check/change the oil given the "fuel in the oil" issues we reported to them as mentioned in this thread.

The oil looked to be completely mixed with gasoline and drained out with the viscosity of water... I wouldn't have thought to change it because we were charged for an oil change, filter, and a complete diagnostic with multiple hours of service to try and troubleshoot the sputtering/backfiring. The repair bill for them shipping it back to us broken (we refused the 11k in repairs) was ~$500 and I am furious with the dealer. We will never be going back there and I am going to file a BBB complaint.

We're within spec on Cylinder #1, which had me really questioning the dealer's diagnostics with us needing a complete rebuild on cylinder #1 (since they also never removed the head). We took them at their word, since they had the machine for months.

They never even changed the oil, or put it back together properly. There were at least a dozen loose bolts and they drove it like that down my driveway when they dropped it back off because the delivery guy didn't want to take our trailer down the 1/4 mile driveway. Thankfully, since they never pulled the head, most of the loose bolts were all just heatshield or cable clips, but still...

The only thing they did right (that they forgot to even list on the invoice) was the gas pedal recall/TSB.

It starts and does not smoke at all. Since we typically do a lot of shorter trips, I will just let it warm up more often in addition to checking the oil a lot more frequently. We've completely lost faith in this authorized dealer, and given Kubota Corporate's lack of wanting to help us, I lost faith in the manufacturer.

I also need to clarify something, because I guess I misread it initially, too. We have 408.4 Miles on the ODO and 100.4H on the hour meter. I was so used to just seeing the hour meter on the tractor when it was running. Like I said... this has very little usage on it, and the dealer would have clearly known how many hours/miles were on it.

 

[Sidekick]

I just wanted to provide an update, as I've finally had some time to sit down with this project again. To be honest, I've been putting it off because I was so upset with how this turned out.

I picked up a new compression tester and finally had time to perform a compression/leakdown test. My values did not match what the dealer reported. As I pulled the plugs, I also noticed a distinct smell of fuel, which I thought to be odd, since they were supposed to check/change the oil given the "fuel in the oil" issues we reported to them as mentioned in this thread.

The oil looked to be completely mixed with gasoline and drained out with the viscosity of water... I wouldn't have thought to change it because we were charged for an oil change, filter, and a complete diagnostic with multiple hours of service to try and troubleshoot the sputtering/backfiring. The repair bill for them shipping it back to us broken (we refused the 11k in repairs) was ~$500 and I am furious with the dealer. We will never be going back there and I am going to file a BBB complaint.

We're within spec on Cylinder #1, which had me really questioning the dealer's diagnostics with us needing a complete rebuild on cylinder #1 (since they also never removed the head). We took them at their word, since they had the machine for months.

They never even changed the oil, or put it back together properly. There were at least a dozen loose bolts and they drove it like that down my driveway when they dropped it back off because the delivery guy didn't want to take our trailer down the 1/4 mile driveway. Thankfully, since they never pulled the head, most of the loose bolts were all just heatshield or cable clips, but still...

The only thing they did right (that they forgot to even list on the invoice) was the gas pedal recall/TSB.

It starts and does not smoke at all. Since we typically do a lot of shorter trips, I will just let it warm up more often in addition to checking the oil a lot more frequently. We've completely lost faith in this authorized dealer, and given Kubota Corporate's lack of wanting to help us, I lost faith in the manufacturer.

I also need to clarify something, because I guess I misread it initially, too. We have 408.4 Miles on the ODO and 100.4H on the hour meter. I was so used to just seeing the hour meter on the tractor when it was running. Like I said... this has very little usage on it, and the dealer would have clearly known how many hours/miles were on it.

That sucks that Kubota never released a fix for the earlier models in colder climates. My dealer told me they had 3 with the problem. Mine needed oil changes at about every 8 hours with the oil being thin like water by then. Kubota never took ownership of that engine and left the dealership mechanics on their own with very little support or debug procedures. So glad they took mine back because it actually caused aggravation and stress every time I used it. I actually am also disappointed in the RTV-X that replaced it. Very hard to shift gears and gutless on hills. I will say the problems I went through with the RTVs actually opened my eyes up to test driving different brands when I recently replaced my Deere that was supposed to be replaced by a Kubota. I love my new Kioti tractor as a result. Hopefully you can get a couple more hours out of yours with frequent oil changes. Sounds like your dealer was just guessing at the problem with no info from Kubota like every other dealer with a bad one.

 

[catalyst]

That sucks that Kubota never released a fix for the earlier models in colder climates. My dealer told me they had 3 with the problem. Mine needed oil changes at about every 8 hours with the oil being thin like water by then. Kubota never took ownership of that engine and left the dealership mechanics on their own with very little support or debug procedures. So glad they took mine back because it actually caused aggravation and stress every time I used it. I actually am also disappointed in the RTV-X that replaced it. Very hard to shift gears and gutless on hills. I will say the problems I went through with the RTVs actually opened my eyes up to test driving different brands when I recently replaced my Deere that was supposed to be replaced by a Kubota. I love my new Kioti tractor as a result. Hopefully you can get a couple more hours out of yours with frequent oil changes. Sounds like your dealer was just guessing at the problem with no info from Kubota like every other dealer with a bad one.

I was worried about the dealer also not knowing about the issue, because the XG850's aren't incredibly common here. I sent them all the links to this thread and similar threads, suggesting Kubota Corporate test my oil, as well. Kubota apparently wanted nothing to do with it. The next machine will be a different brand. Thankfully our Tractor has been incredibly reliable.

 

[lugbolt]

The engines on these really are designed to be run, and run "hard". IOW, when used in such a way where they make frequent short trips, the engine oil never really warms enough to boil off any contaminants, and over time those contaminants (unburned fuel, water vapor, etc) build up. This was/is a big issue on the Kawasaki V-twin mules and the single cylinder Mules. I even had one customer show up twice a year, typically December and then again in February or March, saying he had a blown head gasket-on a Mule 610 which is air cooled. We changed the oil, educated him to use low gear so that the engine would develop some RPM which warms the oil faster, but I don't think he ever did. I heard he ended up buying a Ranger 570. I've never seen this issue on the 570 or any polaris for that matter.

I still think Kubota really failed in the design phase of the 850 sidekicks. It's a market that they tried to get into (gas SxS) but they made many mistakes. That market is better suited to those companies who have a lot more experience with them and/or actually learn from the mistakes that they made and change the product. Kubota introduced the 850 in, what, 2016? And it's remained relatively unchanged, and here we are, 2025 almost. To stay competitive you gotta change them up about every 5 years. Keeping em around too long is not good for sales and it's not good for the company image either. Especially in the off-road vehicle segment. For those folks at Kubota who might be reading this, yes that is a challenge.

 

[mikester]

Personally speaking I'd rather buy a product that's been around a long time and had the kinks worked out than buy something that's essentially a brand new un-proven design every 3-5 years and playing catch up. That's why I prefer Toyota and Honda over Stellantis and GM these days.

It's all expensive toilet paper at the end of the day.

I don't like supporting vendors that don't support their customers.

 

[lugbolt]

Personally speaking I'd rather buy a product that's been around a long time and had the kinks worked out than buy something that's essentially a brand new un-proven design every 3-5 years and playing catch up. That's why I prefer Toyota and Honda over Stellantis and GM these days.

It's all expensive toilet paper at the end of the day.

I don't like supporting vendors that don't support their customers.

I agree but I also will say that Kubota has has the 850 around a while, they know of the issues that plague it, and they STILL haven't changed enough on them to address those common issues. Bad Boy (MTV) had this issue for years along with their mowers. Keep pumping them out with known defective parts (pulleys on the mowers....) and just warranty them. Sure didn't help customer service any when they had to bring their expensive ZT in twice a year for the exact same failed part. They did warranty them until the warranty was up, but that doesn't solve the inconvenience (and costs) incurred by the EU having to carry it to the dealer twiced a year....usually right in the middle of mowing season. Their SxS's just sucked, period. I know the lead designer personally and they were directed by "higher up" to try to "copy" polaris' design as much as possible which they tried to do. But if you remember in 07-13 (IIRC) Polaris didn't have anything worth buying compared to the Yamaha/Kawasaki/Honda offerings, well except the Ranger 800's which were really good units aside from prematurely wearing out suspension bushings and wiring issues. The rest of them was pretty well built. I actually own one and I do like it a LOT better than the RTV I had previously. It's smaller than the RTV, but it rides 1,000,000 times better, runs smoother, quieter, has a LOT more power, hasn't had any issues (yet), and a LOT easier to do basic service on. Only thing I "dont" like is that the RTV was built more for heavy working, although it didn't have the power to do much. The dump bed was nice sometimes but I find that I barely used it anyway. So for what we need it for, the Ranger fits our needs just fine and our backs aren't hurting the day after a ride