Backhoe [RPMS] how little is enough?

[ron45]

Being of frugal...STINGEY German stock I sometimes run Kioti at about 1200 rpms when digging out rocks that are not very large. This is just enough to make the controls responsive. Someone told me once that the hoe should be run up near max rpm from the motor or undesirable chemical changes accumulate in the hydraulic oil. He had a term for it but I don't remember it. I asked about it here once but it was long ago. The consensus was not true. So I just wanted to check about the opposite of max rpm, re minimum rpm needed for the the task. Am I hurting anything working this way? I don't get the sense that anything is under powered. These are small surface rocks and they come right up with little perceived effort on Kioti's systems.

 

[4570Man]

Being of frugal...STINGEY German stock I sometimes run Kioti at about 1200 rpms when digging out rocks that are not very large. This is just enough to make the controls responsive. Someone told me once that the hoe should be run up near max rpm from the motor or undesirable chemical changes accumulate in the hydraulic oil. He had a term for it but I don't remember it. I asked about it here once but it was long ago. The consensus was not true. So I just wanted to check about the opposite of max rpm, re minimum rpm needed for the the task. Am I hurting anything working this way? I don't get the sense that anything is under powered. These are small surface rocks and they come right up with little perceived effort on Kioti's systems.

I don't see any problem. I find my backhoe works pretty good at 1200-1500 RPMs. If I am doing anything "serious" digging I run at the suggested 2200-2400 RPMs because it is much faster. When I am using my backhoe thumb for firewood cutting I ideal at an 1300 RPMs. The backhoe operate much too slow at slow ideal, but spends most of the time doing nothing so I hate to run much faster.

 

[Gary Fowler]

I don't think you would do anything to the hydraulics at that speed, but you may not be doing the engine any good running it at prolonged just barely above idle speeds. It could cause a lot of carbon build up and some say it causes 'wetstacking' (WS) where unburned fuel gets back into the crankcase. I never run my TLB at WOT when digging, it is just too noisy and I don't need the extra RPM to make everything work to my satisfaction. I do find that 2000 RPM is about right for what I do and the hydraulics work plenty fast with just as much power, the engine isn't screaming like it is at wide open throttle (WOT)and it is fast enough so there is no WS nor carboning up of the engine.
I would suggest at least 1500 RPM for removing surface rocks and other easy going operations.

 

[murphy1244]

When working my machine I run at 1800 rpm at least to get the hydraulics up to speed and work the moisture out.

 

[ron45]

Thanks 4570 man. I use to have on of those. Traded it for a welder I needed. I've always regretted it. What is a back hoe thumb? That's a new term for me.

 

[ron45]

Yea, noise is the other issue that got me thinking about lower rpms. Didn't know about the wet stacking. I'll try the 1500. Most of the rocks I encounter are not of the surface type and the ones that are don't require much time at all. Then it on to the bigger ones. Worst case might be 10 minutes. In view of that do you feel it would cause problems.

thanks very much for helping,

Ron

 

[ron45]

Thanks Murfy, I often run it there for serious digging. When driving the tractor to where the work is on grades in 3rd gear I am often at 1800. Is just that sufficient to warm up the hydraulic fluid or should I be letting Kioti do some yoga while we go the the work area?

 

[murphy1244]

Thanks Murfy, I often run it there for serious digging. When driving the tractor to where the work is on grades in 3rd gear I am often at 1800. Is just that sufficient to warm up the hydraulic fluid or should I be letting Kioti do some yoga while we go the the work area?

Yoga is always good for the engine and the soul. Let the PTO spin on a cold day too. Zen and the art of tractor repair...

 

[DK35vince]

Its not hurting a thing.
The backhoe will just be slow at low RPM's

 

[Alien]

I sit on 1800 for most stuff (FEL etc) and 2200 for mowing. Main thing to watch for is that the engine is not labouring. (struggling)

 

[JoelD]

Thumb attaches to dipper stick and let's you have something to clamp things I'm between it and the bucket when you curl the bucket

 

[Buggs67]

FWIW I use 1800 for BH operations and anywhere from 2200-2600 (WOT) for FEL work and moving around.

My tractor is smaller than most here at only 24.5 hp so that may account for difference. I wear earmuffs when operating so engine noise isn't a factor.

And when doing BH work at 1800 I seem to use little fuel.

 

[Xfaxman]

--------. What is a back hoe thumb? That's a new term for me.

More pictures: Click

Mine made from two ripper teeth.

 

[4570Man]

Thanks 4570 man. I use to have on of those. Traded it for a welder I needed. I've always regretted it. What is a back hoe thumb? That's a new term for me.

Here is what I use my thumb for. The thumb is a piece of metal for the bucket to clamp against. Some of the nice thumbs are hydraulic controlled, but few people have those on tractor mounted backhoes.

 

[Gary Fowler]

Here is what I use my thumb for. The thumb is a piece of metal for the bucket to clamp against. Some of the nice thumbs are hydraulic controlled, but few people have those on tractor mounted backhoes. View attachment 457362

What is the old saying about never going back, well if you ever use a hydraulic thumb, you will never go back to a fixed or manually adjusted one. I can pick up anything from hen egg sized to maximum lift sized rock or other object and never leave the seat to adjust anything. Between picking up and digging, you have to move the thumb so it lays against the dipper stick and out of the way so a fixed on has to be constantly adjusted. In my soil there is always a rock(s) encountered that sometimes need to be picked up and moved so the thumb is always used. Hydraulic ones are costly to install but worth every penny especially if you are physically challenged for getting on and off the tractor.

 

[Industrial Toys]

I thought Wet stacking was the result of running a Diesel at little load. I did not know that RPM had a bearing on it.

OP As a stingy German, just be glad you don't own a Manheim Built JD!

 

[ron45]

JoelD I have something like that but it has an arc of teeth about the size of your thumb shaft, it's also bent in an arc with the inside of the curve facing the boom and bucket. I should have gotten it just from the word thumb. Hands are much more useful with one of those. Thanks a bunch for the pic.

 

[K Arno]

Run my tractor near full power for PTO driven tasks like running the snowblower. Just picked up one of these: Backhoe Thumb Excavator Bolt on Universal Claw Tractor Attachment Kubota Deere | eBay

 

[Buggs67]

Run my tractor near full power for PTO driven tasks like running the snowblower. Just picked up one of these: Backhoe Thumb Excavator Bolt on Universal Claw Tractor Attachment Kubota Deere | eBay

I was interested in this also but it's max dipperstick width is 3 1/4" and mine is 3 3/8"!!

 

[MossRoad]

For what its worth, when I had my IH2500b, which was a 50hp HST tractor loader, the operator's manual specifically stated to run it at PTO speed all the time. This was for a couple reasons. One being proper cooling of the hydraulic fluid. Too low of an RPM and it heated up the fluid too much while not forcing it through the cooler fast enough, which decreases internal component and fluid life. Another reason was braking response when driving. Not brakes, but hydraulics in the tranny. You know, when you let off the direction pedal on an HST tranny, it stops the tractor without using brakes. The manual specifically mentioned that. Other reasons listed were response time of the FEL controls, 3pt lift, and draft control.

But, that all may have been specific to just mid-70's IH HST tractors. Consult your operator's manual and see of it says anything about engine RPMS.