Sidekick RTV-XG850 backfiring / loss of power

[Siesta Sundance]

This is a Kubota, not cheap Mule and sold as a worksite model that won't see a lot of wide open throttle. I have never had a problem like this with a piece of machinery and definitely thought Kubota would state something like not for homestead use in the sales literature if that is the case with the Subaru engine. Like I said a friend bought a Polaris 1000 with the exact same use and no problems so it's definitely not a problem for all manufacturers. I definitely made a mistake buying the sidekick and hopefully others will have this knowledge about the Sidekick before making the same mistake as I did.

HA ha cheap mule... the $11k or $12k basic 4000 or 4010 mule is 100% Japanese made just like my L305DT Kubota Tractor. The Kawasaki mule is very dependable, quality made, workhorse for your use, it will out last any of the Kubota gas models. Kawasaki has made minimal changes to it over the years and it's a proven designed and a well functioning machine. I know a few people who has or owned, have issues with the Kubota gas/diesel UTV's. I heard kubota is putting china "Kubota made" diesels in some of thier newer models.

Honestly, in general Kubota is slowly selling us out, I've noticed quite a few things in parts and with filters... all made in CHINA, bought from the parts department of 2 different Kubota dealers.

 

[lugbolt]

Polaris designed the Prostar engine from the get-go specifically for the application.

The Mule V-twins are lawn mower engines, designed to run 3500 rpm all day. In the mule, they don't.

Kubota used a subaru design, which was NOT designed for the application-rather only slightly modified to work. They knew it and I knew it, the day I saw the prototypes. I advised the japanese engineers of the issues we saw with the Mules and what they did with what I was saying is up to them. Maybe they didn't care maybe they didn't understand (again, the joys of dealing with a japanese company...) or maybe they did care and understand, yet chose to do it their way. Who knows. Or maybe they just thought I was a stupid grease monkey. No telling, couldn't understand them anyway. I don't speak japanese and they don't speak much english.

Oddly enough Polaris used to use Fuji engines way back in the day. Subaru was (is??) a subsidiary of Fuji. Subaru engines are marketed in the North American market as "robin" engines. I work on a few a week at work, good little engines in that application although the vast majority are 360 degree firing order twins. They vibrate a lot, but they run quite good-and last nearly forever as long as they're not dusted or run outta oil. Even run outta oil the lifters just collapse and it quits. Lot of times dump 2 quarts into it and it'll fire back up and run another few years til the lifters are just worn out. Good little engines just vibration prone.

I stand behind my comments until engineering proves me wrong. The sidekick engine was not really designed to run at low speed/idle like the diesels are, which results in "making oil" over time. I recommend using low range as much as possible, to keep the RPM up which is also easier on the belt drive.

 

[BunkerSea]

Lugbolt, do you think Kubota with the redesigned Sidekick engine for 2023 probably would have addressed the fuel dilution problem.

 

[mikester]

Lugbolt, do you think Kubota with the redesigned Sidekick engine for 2023 probably would have addressed the fuel dilution problem.

Note to OP

I just saw an ad in our local farmers finder 2021 kubota sidekick 1,500km asking CDN$23,500

here's another ad asking only CDN$24,500

https://www.autotrader.ca/a/kubota/rtv-xg850%20sidekick/durham/ontario/19_12671189_/?ms=motorcycles_atvs&showcpo=ShowCpo&ncse=no&orup=1_2_2&sprx=-1

are people actually buying at these prices? I should sell mine but then I'd need to find something to replace it...

 

[ANZAC]

Hi, I have a 2018 Sidekick with the same issue. Brand new plugs. It seems to come off idle a little better but if I floor it, there's a big flat spot at the revs increase and I can get up to 25, maybe. Sounds like identical symptoms.

Just did an oil change and that looked normal.

Gas is fresh, though I don't know what was in the tank when I bought it (used).

Could pretty much only be coil pack or injectors at this point unless there is a design issue....


(edit)
Same as the OP who noted slightly different condition of old plugs, I did have one which was a little darker than the other, but neither was fouled at all. Replacing the plugs has improved the performance coming off idle but at WOT it seems to get to about 25 or 27 and run out of steam (in high range). There is some black exhaust smoke, which lends credence either to the earlier post of mixture too rich, it could also point to valve clearances but checking/adjusting valve clearances is a big pain.

I've also just replaced the throttle pedal and bracket with the later design, so did go through the adjustment procedure so I know the throttle pedal is making WOT at the throttle body.

Maybe I will run this tank of gas all the way down to nothing, then fresh gas and see if that helps. (It was half full or something when I gassed it up)

 

[catalyst]

Our XG850 has now been at the local dealer almost a month. They are at a bit of a loss as to what the issue is - They seemed shocked that it has a Subaru engine and that they did not have the diagnostic tools for that specific engine and also tried telling us the ECU is from a 2022 XG850, which is impossible because this is the first time it has been to a dealer since we got it in 2020.

On a positive note, the recalls for the intake pipe and power steering shaft have been fixed. Is there not also a recall on the gas pedal?

 

[ANZAC]

Our XG850 has now been at the local dealer almost a month. They are at a bit of a loss as to what the issue is - They seemed shocked that it has a Subaru engine and that they did not have the diagnostic tools for that specific engine and also tried telling us the ECU is from a 2022 XG850, which is impossible because this is the first time it has been to a dealer since we got it in 2020.

On a positive note, the recalls for the intake pipe and power steering shaft have been fixed. Is there not also a recall on the gas pedal?

There's no recall or campaign on the gas pedal. There is a kit for the very early models (2018) that replaces the bracket and pedal. These parts were running production changes, so if yours was made in 2020 it likely has the updated parts. I upgraded mine, it was an easy job. I used a wifi camera to watch the throttle body while adjusting the new pedal. The individual parts are cheaper than the kit, but you don't get the instructions. If you have the shop manual, then you won't need the instructions.

 

[ANZAC]

Update: my Sidekick seems to be doing a little better. It does get a bit fouled if I let it idle too long, then I have to rev it a bit in neutral and it is good after that. I'm using more of the gas that was already in the tank and will put a fresh tankful in it once I empty it.

 

[catalyst]

Update - dealer still has the XG850. They had to order all new tools and testing equipment because they did not have the tools to properly test this specific model.

We just got a call today for an authorization for work - they want to remove the head to inspect the valves - and mentioned a possible head/valve replacement, but they were also not sure that would fix the issue.

We asked what happens if that does not fix the issue and is Kubota willing to help on any of the costs or diagnostics. We have relatively low hours (~400) and are just outside the warranty period - as would be our luck.

He did indicate that they never see this version with our Subaru motor, but Kubota has now changed to a Kubota branded motor.

400 hours seems a little low for a complete head replacement... We're not even riding this thing hard...

 

[mikester]

Update - dealer still has the XG850. They had to order all new tools and testing equipment because they did not have the tools to properly test this specific model.

We just got a call today for an authorization for work - they want to remove the head to inspect the valves - and mentioned a possible head/valve replacement, but they were also not sure that would fix the issue.

We asked what happens if that does not fix the issue and is Kubota willing to help on any of the costs or diagnostics. We have relatively low hours (~400) and are just outside the warranty period - as would be our luck.

He did indicate that they never see this version with our Subaru motor, but Kubota has now changed to a Kubota branded motor.

400 hours seems a little low for a complete head replacement... We're not even riding this thing hard...

Thanks for the update, keep us posted withnthe results. Good luck!

 

[catalyst]

Got a call from the service manager today - We pushed back a little with the dealer, and asked if there is anything Kubota can do to assist with the problem, since we're just outside of warranty and this sounds like a major issue.

The dealer is also frustrated because it sounds like the tech has a LOT of time invested in trying to go back and forth with Kubota on trying to resolve the issue. The dealer initially didn't have the diagnostic tools for the Subaru motor and had to order everything to work on our XG850. I am being told there is lower compression at operating temp on driver's side (cyl 1?).

Kubota is suggesting to pull the head and inspect pistons.

The tech did not sound satisfied that doing head/valve work would fix the issue, but this is what Kubota is suggesting. I also reported that we were getting backfiring under load even at engine cold - not just at temp. They did not really have an answer for that.

At any rate... the dealer is asking Kubota for "good will". If that fails, they said we as the customer should ask for "good will" and if that fails, we are going to talk about costs and options. We're pretty frustrated because our XG850 has been down for 3 months.

Our machine only has ~400 hours on it and is only used around our rural property for mild work. It has NEVER seen a trail.
It is a 2020 Kubota RTV-XG850

If they can't help with this, I don't think we'll ever buy another Kubota product again. Has anyone else had to request good will from Kubota and if so, how did that work out for you?

 

[Siesta Sundance]

Got a call from the service manager today - We pushed back a little with the dealer, and asked if there is anything Kubota can do to assist with the problem, since we're just outside of warranty and this sounds like a major issue.

The dealer is also frustrated because it sounds like the tech has a LOT of time invested in trying to go back and forth with Kubota on trying to resolve the issue. The dealer initially didn't have the diagnostic tools for the Subaru motor and had to order everything to work on our XG850. I am being told there is lower compression at operating temp on driver's side (cyl 1?).

Kubota is suggesting to pull the head and inspect pistons.

The tech did not sound satisfied that doing head/valve work would fix the issue, but this is what Kubota is suggesting. I also reported that we were getting backfiring under load even at engine cold - not just at temp. They did not really have an answer for that.

At any rate... the dealer is asking Kubota for "good will". If that fails, they said we as the customer should ask for "good will" and if that fails, we are going to talk about costs and options. We're pretty frustrated because our XG850 has been down for 3 months.

Our machine only has ~400 hours on it and is only used around our rural property for mild work. It has NEVER seen a trail.
It is a 2020 Kubota RTV-XG850

If they can't help with this, I don't think we'll ever buy another Kubota product again. Has anyone else had to request good will from Kubota and if so, how did that work out for you?

Tell dealer to credit you well on a trade, buy the diesel version.

 

[catalyst]

Well, Kubota denied the "good will" gesture. The dealer indicated that on a 2nd owner machine, that is typically the case. We bought it off another couple with 100 hours on it. They were older and couldn't deal with the jumpy gas pedal. The dealer is providing us with information/diagnostics and suggesting we ask Kubota directly. They apologized profusely for the bad news.

The dealer said we have excessive blowby on cyl 1 and is quoting us at $4500 for the repair. I don't understand how you get this type of major failure on a 2020 machine with only 400 hours on it without some type of manufacturer defect.

We are besides ourselves at this point. 5k in repairs on a 2-3 year old machine!?!?

Please any ideas or suggestions would be appreciated at this point. This makes me question our tractor purchase. We have a bunch of orange items in the barn, and this has me questioning them all.

 

[GreensvilleJay]

Kinda late here but WHAT make/model is the engine ? If not Kubota, check with the real manufacturer for help ?
FYIW..
Kubota Canada gave me some nice 'goodwill' last year, on my 5 years old, 1100 hr BX23S with a defective loader frame.

 

[mikester]

I'd probably look for a small diesel motor or electric conversion at that price. Or trade in for a different machine.

 

[Siesta Sundance]

Well, Kubota denied the "good will" gesture. The dealer indicated that on a 2nd owner machine, that is typically the case. We bought it off another couple with 100 hours on it. They were older and couldn't deal with the jumpy gas pedal. The dealer is providing us with information/diagnostics and suggesting we ask Kubota directly. They apologized profusely for the bad news.

The dealer said we have excessive blowby on cyl 1 and is quoting us at $4500 for the repair. I don't understand how you get this type of major failure on a 2020 machine with only 400 hours on it without some type of manufacturer defect.

We are besides ourselves at this point. 5k in repairs on a 2-3 year old machine!?!?

Please any ideas or suggestions would be appreciated at this point. This makes me question our tractor purchase. We have a bunch of orange items in the barn, and this has me questioning them all.

If that is the true diagnosis/defect they found. Mechanicaly inclined? Pick up your machine, buy a engine rebuild kit, rebuild it, then sell it.

 

[catalyst]

If that is the true diagnosis/defect they found. Mechanicaly inclined? Pick up your machine, buy a engine rebuild kit, rebuild it, then sell it.

It is the older design Subaru motor that seems to be problematic with these machines.

Either way, we are into to the dealer for 5hrs diagnostics, the there is still a sizable bill. They actually have a lot more time in it than that, but 5hrs is what is on the books - so we're told. It was also in for a couple of recalls.

I did requested pricing on the new "Kubota" motor going into these machines. $4500 is pretty steep on a 3 year old machine that has never even seen a trail, and i feel like fixing the Subaru is just asking for more trouble given some of the other posts.

We are still waiting on the info from the dealer to call Kubota and request "good will" as customers. The district guy told us that Kubota typically won't extend good will on a 2nd hand purchase. We bought it almost new with 100 hours on it from an elderly couple who couldn't deal with the "jumpy" gas pedal.

If they deny assisting us, I hate to say it, but this will be the last Kubota product I ever buy and I'll likely look into trading/selling our Tractor and Zero turn, as we've also had small but continued issues with both. The local dealer is about 1.5 hrs away and we have other brands that are quite a bit closer, if the machines are problematic and need repeated servicing.

I am amazed Kubota isn't trolling these forums like Dodge/Ram does. This is huge egg on Kubota's face.

 

[Siesta Sundance]

It is the older design Subaru motor that seems to be problematic with these machines.

Either way, we are into to the dealer for 5hrs diagnostics, the there is still a sizable bill. They actually have a lot more time in it than that, but 5hrs is what is on the books - so we're told. It was also in for a couple of recalls.

I did requested pricing on the new "Kubota" motor going into these machines. $4500 is pretty steep on a 3 year old machine that has never even seen a trail, and i feel like fixing the Subaru is just asking for more trouble given some of the other posts.

We are still waiting on the info from the dealer to call Kubota and request "good will" as customers. The district guy told us that Kubota typically won't extend good will on a 2nd hand purchase. We bought it almost new with 100 hours on it from an elderly couple who couldn't deal with the "jumpy" gas pedal.

If they deny assisting us, I hate to say it, but this will be the last Kubota product I ever buy and I'll likely look into trading/selling our Tractor and Zero turn, as we've also had small but continued issues with both. The local dealer is about 1.5 hrs away and we have other brands that are quite a bit closer, if the machines are problematic and need repeated servicing.

I am amazed Kubota isn't trolling these forums like Dodge/Ram does. This is huge egg on Kubota's face.

Every brand has its problems or should I say problem child models etc.

I do wonder about future products and maintenance items from Kubota.

I starting to noticing many maintenance items bought straight from the dealer, but the parts/filter or hose etc are made in CHINA. But lots of manufacturers are sourcing products from CHINA as well.

 

[mikester]

It is the older design Subaru motor that seems to be problematic with these machines.

Either way, we are into to the dealer for 5hrs diagnostics, the there is still a sizable bill. They actually have a lot more time in it than that, but 5hrs is what is on the books - so we're told. It was also in for a couple of recalls.

I did requested pricing on the new "Kubota" motor going into these machines. $4500 is pretty steep on a 3 year old machine that has never even seen a trail, and i feel like fixing the Subaru is just asking for more trouble given some of the other posts.

We are still waiting on the info from the dealer to call Kubota and request "good will" as customers. The district guy told us that Kubota typically won't extend good will on a 2nd hand purchase. We bought it almost new with 100 hours on it from an elderly couple who couldn't deal with the "jumpy" gas pedal.

If they deny assisting us, I hate to say it, but this will be the last Kubota product I ever buy and I'll likely look into trading/selling our Tractor and Zero turn, as we've also had small but continued issues with both. The local dealer is about 1.5 hrs away and we have other brands that are quite a bit closer, if the machines are problematic and need repeated servicing.

I am amazed Kubota isn't trolling these forums like Dodge/Ram does. This is huge egg on Kubota's face.

Interesting to hear you are also having issues with your tractor and ZTR

 

[Sidekick]

Well mine is still pouring gas in the crankcase and even still under warranty Kubota is ignoring it. I have emails from others with similar problems and am thinking there may be major design issues with the Subaru engine Kubota is trying to hide. Just got an email from a guy saying a replacement starter for them is $700.00 just to buy if you can find one. I made a big mistake being loyal to Kubota. Awful lot of low hour used ones available and I wonder why.