kioti 1200 backhoe hydraulics

rlpearce · Feb 20, 2015

New guy here, looking for answers to my hydraulic problem. I purchased a Kioti 1200 backhoe which came with a small PTO pump. I mounted it (3 pt.) onto my old Massey 35 and removed it's much larger PTO pump in order to put the smaller one on that came with the backhoe. The backhoe worked great (after I installed a splitter valve so I could direct pressure to the FEL or the backhoe) but the FEL was VERY slow and had little lifting power. I then removed the small PTO pump and put the larger one back on. Then the FEL worked properly again but when I switched the splitter to the backhoe it would load the engine and the backhoe was noisy and had little power. I assumed I was overloading the backhoe system so I bought and installed a Prince adjustable relief valve and put it in the backhoe line just after the splitter. If I back it off all the way then the tractor doesn't load up but the backhoe has no power, which makes sense. But as soon as I start to increase the pressure at all, the engine will load whenever I select the backhoe, and the backhoe still has very little power, nothing like when the smaller pump was used. I don't know if the Kioti backhoe is open or closed center, I assume the tractor is open. I wrote to Kioti to ask what the operating pressure was supposed to be, but they didn't even answer me. Hopefully one of you that knows hydraulics better than I do can help. I need both the FEL and the backhoe to work, but right now it's one or the other. It also would be great if I could find a source for a manual for the backhoe.

Leejohn · Feb 20, 2015

Sound like you are not using the PB port coming off the BH to feed the BH.

J_J · Feb 20, 2015

Most of the Kioti KB backhoe pressure rating is 2466 psi.
-------------------SB ------------------------------1875 psi.

It is hard to follow exactly what you did with the hyd.

A PTO pump and valve has it's own hyd circuit.

The pump has a pressure rating and that will determine the power. The pump GPM will determine the operating speed.

What is the pressure reading using the PTO pump, and the cyl fully extended.

What kind of splitter did you use?

.

Coyote machine · Feb 20, 2015

Welcome to TBN.:thumbsup: Sounds like Leejohn may be on the right track. PB=power beyond, BTW.
I'm not a hydraulics guy so I'll bow out. Good luck.

J_J · Feb 20, 2015

If he is using a PTO pump, that is a separate circuit.

Not even sure where the splitter is being used.

J_J · Feb 20, 2015

Leejohn said:
Sound like you are not using the PB port coming off the BH to feed the BH.

Don't understand what you are saying here.

rlpearce · Feb 20, 2015

OK, I'll try to be more specific. Originally, the tractor used a PTO pump that was plumbed pressure side to the valves (FEL only), other side of valves to tank, tank to PTO pump intake. FEL worked fine. Originally the backhoe was plumbed with it's own (smaller) PTO pump and it's own tank. When I hooked up the backhoe I did not use the backhoe tank. I did use the smaller PTO pump and used a tee to supply both the backhoe and the FEL, with two separate returns to the tank. That didn't work, as pressure could go back through the tee and other set of valves (and back to tank) when operating either the FEL or Backhoe. That's when I install the (manual) splitter valve, simply selecting the pump output to go either to the FEL valves or to the backhoe valves, both still having their own return lines to the tank. That worked fine for the backhoe, I was actually amazed at how much power it had. But the FEL was then very slow and had very little lifting power. I figured the pump was too small. By the way, I used to be a professional auto mechanic (20+ years) so I'm OK with most mechanical things, I just don't have that much experience with hydraulics, other than brakes. So back to the backhoe. Since I figured the pump was too small, I put the larger PTO pump back on and plumbed it exactly the same way as the smaller pump had been. Output to splitter, inlet from tank, both valve sets with return to tank. Now with the FEL selected with the splitter, the FEL worked fine again. But when the backhoe circuit was selected, I got a decrease in RPM's and the engine was obviously loading, with all backhoe valves in the neutral position. The backhoe valve body was also now noisy. (it wasn't with the smaller pump) I figured I was overloading the backhoe, either with pressure or volume. So I bought and installed a Prince adjustable relief valve between the splitter and the backhoe valve set. The relief valve dumps excess back to the tank. With the relief valve backed all the way off the engine doesn't load, but the backhoe doesn't work either. As soon as I start putting pressure on the relief valve spring, the engine will start to load, I still have noise at the backhoe valve body, and although the backhoe works, it has very little power. I haven't cranked up the relief valve for more pressure, because I don't want to damage the backhoe controls, not knowing exactly what is going on. I don't have a pressure gauge on the system, so I don't know what kind of pressure either pump is putting out. The original PTO pump is at least twice as large, physically, as the backhoe PTO pump. If I'm not explaining the plumbing well enough, I can try to make a drawing and figure out how to post it on here.

J_J · Feb 20, 2015

If the engine is working hard using the pump. then something is blocking the flow.

On some of the splitters, the Excess flow has to go to tank, so please provide the model number and name of the splitter.

The size of the pump only dictates the operating speed.

The higher pressure pump will provide the most power.

I think your problem is in the splitter.

Leejohn · Feb 20, 2015

Yes I would say now the spltter not plumbed right or something wrong with it. How many ports are on the splitter?

rlpearce · Feb 20, 2015

I don't remember for sure but the splitter appears to be this one, with the standard selector spool.
Prince Hydraulics > Products > Hydraulic Valves > Selector > Model SS

All this splitter does is to direct pressure to one port or the other. And it (the backhoe) works perfectly when using the smaller pump with the splitter. I only have a problem with the backhoe when I put the larger pump on. I don't understand how the splitter can be the problem, can you enlighten me please? Always willing to learn.