Turn up the kubota

[hondajoe]

Anyboby doing this but me.Turning up the pump plus rpm max 3600 rpm.

[aurthuritis]

i don't know anyone personally,but i have read several discussions. never had anyone ever post the results. would you?

[10-e-c-dirt]

I ask about the same question about a year ago, No one replied.
On farm tractors we have advanced the pump a degree or 2, adjusted the max RPM's 1 or 200 rpm's, on some of the older Bosch pumps it is real EZ to turn the fuel up.

A good Injector shop might shed some light on the subject for you. My way of thinking 2 or 3 horsepower would be great, about a 10% increase.

We turned up an old IH D268 engine, dynoed @ 91 HP pto @ 3200 engine RPM, in all Honesty, I don't think the dyno operator calibrated the Old M & W dyno correctly.. But it sure pulled good and blew heavy Black Smoke, HaHa

[hondajoe]

Well adjusted max fuel at pump bust the cap off and turn out !! about 1 turn this made it smoke just a touch under hard load.Seemed to add grunt at mid range.Then I turned max rpm to 3600 wich was about 3300 stock.Now this wont turn this into a hero but it will run at rated specs.15-16 mph in low range very good power.25-26 high range desent power but will still not hold hills good.Not enough hp to hold this hydro in high range.JOE

[aurthuritis]

do you or anybody else know what the factory spec RPM is on these RTV? no load and stall RPM? i wonder if the machines could be underated some at the factory?

[aurthuritis]

did a little googleing. i "THINK" the max engine no load rpm on the D1105-E4 engine family is 3800 rpm. it seems Kubota uses these engines in many different applications from mowers to generators and other stuff. if you look at the specs it appears they de rate the rpm to get the desired HP. i wonder if most RTV are running 3000 rated rpm. i need to check mine and see.

[aurthuritis]

after some more reading it seams that Kubota in order to meet the tier 3,4 and so on would test their engines at different rpm in order to meet particulate standards. i think there has been some design changes in the combustion chamber and piston crown also,but in order to meet emissions standards without a complete new engine kubota just played and tweeked the fueland rpm until they could get in under the wire. no blue def or cat converters HOORAY

[aurthuritis]

just checked my X1100C. 3145 no load warm engine.

[hondajoe]

I think you could turn your rpm safely to 3600.That would make about 25 % more usable rpm.You will see the difference.You could do 3800 also but on a long down hill you could over run the govt slightly.I have mine run 30 mph on a down hill wide open JOE

[aurthuritis]

Originally Posted by hondajoe

I think you could turn your rpm safely to 3600.That would make about 25 % more usable rpm.You will see the difference.You could do 3800 also but on a long down hill you could over run the govt slightly.I have mine run 30 mph on a down hill wide open JOE

I concur with your observation. before i fool with the governor though i want to do just a little more research and check the RPM on my 07 model too. i think the engines are the same but they do have a different designation number. i think in order to meet the tier regulations that Kubota may have changed the head a little and maybe the piston crown some. i need to check the part numbers to see what changed. it could be that they just turned down the RPM some in order to meet regulations but i would bet there were some slight changes elsewhere.

[soccertoad20]

Any more updates on this?

I have the x1100c model. How would I go about turning it up a little? I don't want to be rolling coal and pushing the engine to the max, but a little extra HP would be nice. I would imagine the engines are slightly tuned down from factory for a safety factor.

[aurthuritis]

Originally Posted by soccertoad20

Any more updates on this?

I have the x1100c model. How would I go about turning it up a little? I don't want to be rolling coal and pushing the engine to the max, but a little extra HP would be nice. I would imagine the engines are slightly tuned down from factory for a safety factor.

first get yourself a tach. then after you confirm your RPM in case you want to return it to it's former condition,you will need to break the seal on the throttle stop screw on the injector pump and back out on it and confirm on the tach that you aren't exceeding 3600 RPM. DO THIS AT YOUR OWN RISK. you won't need to mess with the fuel delivery screw if you do this first.

[10-e-c-dirt]

Originally Posted by aurthuritis

first get yourself a tach.

OK, Where do I get one??? Which 1 would you recommend for a RTV?

[hondajoe]

The easiest way to tell if your real lean is to stick your finger in the tail pipe. No black finger your lean seems to me many with older units would plug their spark arresters .Theirs were tuned right mine at 50 hours had no black in pipe at all now at 10 hour checks a little black on my finger.After you set max rpm you will still have to set fuel rate but check to see where your rpm is at you don't want to twist this thing to hard.You need to check at crank with a photo hand tack their cheap tape on crank pulley and good to go. Hope this helps JOE

[aurthuritis]

Originally Posted by 10-e-c-dirt

OK, Where do I get one??? Which 1 would you recommend for a RTV?

google "Photo Tach" or "Laser Tach" i don't know what brand is the best.

one thing to remember before you turn up the fuel---more fuel doesn't always mean more power. if the fuel air mixture is incorrect you could actually cool the combustion causing more soot and less power. if you choose more fuel i suggest a turbo so you can use the fuel properly. i think the increase in RPM will give you most bang for the buck.