kioti 1200 backhoe hydraulics

[rlpearce]

BTW, meant to say flow control VALVE, not "flow control pump" in previous post. Brain speed not keeping up with fingers. Sorry.

 

[J_J]

I don't think you understand how the hyd works.

Any power the BH develops by the cyl working, is determined by the load resisting the volume/GPM's, and therefore develops pressure and henceforth power.

The amount of GPM flow into the hyd circuit determines the speed of operation.

If you feed the BH 5 GPM, it will operate at a certain speed and develop power.
\
If you feed the BH with 10 GPM, the BH will work twice as fast, but only develop the same power.

With all valves in neutral, the engine should not be loading or straining to maintain power.

If your relief is going off in neutral, then there is a flow problem. There should be free flow from the pump to tank.

Small or large pump doesn't matter much, except for the speed of operation. Thing is, do you want fast, and if not, lower the engine rpm or if the BH flow is from a valve, you can throttle the valve.

In my post above, I have posted what you need to slow the BH to an acceptable speed.

The simple no-cost way to slow the hyd is to reduce engine rpm.

If you install a hyd gauge in a tee in the IN port of the first valve, you can see any pressure that is being developed.

Do you have a diagram of your hyd plumbing?

All valves in an open center hyd circuit should be in series, with PB feeding the next valve, and all tank ports going to tank.

 

[rlpearce]

This is very frustrating. J.J., I understand hydraulics better than you apparently think I do, but I still can't explain what is happening, and you haven't either. Don't get me wrong here, I want and appreciate your help, but we don't seem to be on the same page. As far as a diagram goes, let me try and put it into words:
Tank to pump inlet
pump outlet to manual splitter valve
splitter valve (one side) to FEL controls
FEL controls out to cylinders, one port back to tank
splitter valve (other side) to adjustable pressure relief valve
pressure relief valve, one side to BH, one side to tank
BH controls, IN from pressure relief valve, OUT to tank

I'm not very good at drawing but if that doesn't explain it let me know and I'll try to draw it out for you.
Once again, what I don't understand, especially if big or small pump makes little difference except for potential GPM, is that with the small pump the BH works fine, at all engine speeds. There is little or no engine loading with BH valves in neutral and BH selected with splitter. Then, changing nothing else except the pump, (to the larger one) and with the engine at idle, engine RPM will drop, indication some loading when the BH is selected with the splitter. This is with only a minimal pressure adjustment at the relief valve. And at this setting the BH has very little power. It is obviously not getting enough pressure. I have not cranked it down to a higher pressure because there is obviously something going on here and I don't want to damage the BH. That's why I have asked you if it is possible that the Kioti controls could have small enough passages that they overly restrict the flow of the larger pump, causing the back pressure that would cause the engine loading. If this is the case then the relief valve in the Kioti controls would/is opening, causing the noise that I'm hearing and the loss of pressure and flow to the BH. Given that the ONLY thing that has changed in the two scenario's is the size of the pump, that's all I can come up with, and that's why I asked you if a flow control valve might be the answer.

 

[Leejohn]

Check the hoses you had made and make sure a restricted fitting didn't get put on my mistake. It has happened to me.

 

[rlpearce]

Thanks LeeJohn, I'll recheck the entire path from the splitter to the BH.

 

[Coyote machine]

That is exactly what the splitter is for, and does. When using the backhoe there is no power to the FEL and vice versa.

BTW, I did not say the FEL has no power when the hoe circuit is in use; it has reduced lift as a result of most hydraulic flow being directed to the hoe's use.

Have you removed the filter you put on the tractor to see what if any difference it makes?
Seems to me you've got too many variables going on at once, pumps, selector/splitter valves, filters, etc.
If you go back to square one, you might have a better chance of reaching the correct outcome. JMHO.

 

[rlpearce]

Coyote machine, my apologies if you thought I mis-quoted you. I was just saying what the splitter does in my application. I should have been more specific. I have thought about the filter, and will probably replace it "just because" but the FEL, the BH and the pressure relief valve all have separate lines that tee together before the filter so if it were plugged the FEL should be loading the system as well. The pressure relief valve does need to go, or at least be turned all the way up so that it just passes fluid straight through. It is just creating the kind of back pressure I'm trying to get rid of. If I'd thought things through a little better I'd have realized that before I put in on. The real issue here has to be back pressure in the BH circuit and if the hoses are all good/open then that pretty much leaves the BH controls themselves. I also just got off the phone with a local Kioti dealer who thinks that the higher volume pump is probably causing cavitation in the BH valve system and has recommended installing a flow control valve that dumps excess volume back to the tank. What's another $100 at this point. That's what I'm going to try anyway, and will post here with the results.

 

[Coyote machine]

Thanks, I just wanted to clarify how my tractor/hoe works in case it might be useful to you in your attempts to solve your particular situation.
I'm no hydraulics guru by any means, but I do know from experience that if things are added like filters and a bunch of valves, controls, etc. and things aren't working right, sometimes going back to move forward helps sort things out.

I wasn't thinking the filter was clogging as much as it might be restricting flow due to it's micron rating/filtering media, and thus contributing to the relief valve whining under certain circumstances.
Personally, I think you need to slow things down, maybe take a day off, or two, and think things out from square one.
Most problems have a remedy, it's just not always apparent.

Maybe consult more with your local Kioti dealer OR someone like Bob or Tony at MIE, (Michigan Iron/Equipment) approved TBN advertisers, and Kioti dealer, who is also an engineer who designs many Kioti mods., some of which we've collaborated on; custom adds to their offerings to fit my specific specs. Give them a call and tell them what you're trying to do, they might have some answers.

FWIW, one other suggestion, try making some paragraph breaks in what you write, to make it a little easier on our brains to follow what you're saying. Otherwise things just run on into each other, and it's harder to catch your drift.:thumbsup:

BTW, where's Maupin?

 

[J_J]

If you think the BH valve is small for the pump flow, just run the engine at a decrease speed to match valve GPM requirement.

Are you using a splitter with equal flow or a priority flow control.

With the priority flow control, you can set the priority flow and the rest of the pump flow goes through the excess flow for another circuit or to tank.

As far as the pressure relief valve, just set it higher than the first valve or pump rating. or remove the relief valve and install a no-relief valve.

This will put your relief for the hyd at the first valve relief setting.

But then, if the two valve relief setting were the same, it will not make any difference.

What is the size of your pumps and splitter flow rating in GPM?

 

[rlpearce]

In case this might help someone else with a similar problem, I have (mostly) solved the issue regarding my BH/FEL hydraulics. The issue was actually TWO problems. First, the original (larger) PTO pump is apparently pretty much worn out and although it produces plenty of flow, it is not producing much pressure unless the engine is revved up fairly high. I should have mentioned before that although it lifted the FEL fine, it required high RPM's to do so if there was much weight in it. The second issue is that the pressure relief valve that is in the circuit before the splitter valve was set much too low. Which explains why I could hear it squealing when using the FEL at high rpm's. After putting the smaller pump back on and adjusting the pressure relief valve for a higher pressure, both the BH and FEL work, although the FEL works quite slowly, but it does lift a full bucket of dirt, gravel, sand, etc. So the real repair now appears to be rebuilding or replacing the original pump, and using the Prince adjustable flow control valve to limit the flow to the BH while still maintaining adequate pressure. Thanks to all of you who chimed in on this to help solve the issue.

 

[J_J]

A flow control test kit would have solved all the problems and indicated the pressure and flow from each pump.

A good hyd pump will produce the flow and the ability for the other hyd components to develop the pressure.

So, if you have to rev the engine to get pressure and lifting force, then you know the pump is at fault or the other hyd components are leaking.

A flow test bypasses everything except the pump.

A good hyd pump pushing 2 GPM, will allow the hyd components to develop the same pressure as a 10 GPM pump. The 10 GPM flow rate will make things move faster.