3 Point Hitch Lift Control on Kioti LK35

[Tx Jim]

James aka k0ua
I'm a firm believer that information posted on the internet should be "accurate" not someones "opinion" especially on a tractor forum. I will not tell you to shut up. I'm getting a little long in the tooth but still not too old to learn. On most tractors I've been acquainted with the 3 pt control valve is the last valve to get hyd power. So please explain why the FEL control valve has 2 return ports(return & PBY) and how a needle restrictor valve will cause a relief valve to unseat? I think 2 return ports is to accommodate the excess flow of higher output hyd pumps. Older open center hyd systems only had one(1) return port(hose).
Thank you for your patience,Jim

 

[Tx Jim]

Are you talking about putting the needle valve interrupting the flow in the power beyond loop, or between the 3pt control valve & the 3pt cylinders? In the power beyond loop would mess things up & restrict hydraulic flow to everything. I'm not aware of any issues other than slowness for a restriction after a work port.

Let's discuss for the moment a tractor without a frt end end loader then if I'm thinking correctly there will be no PBY loop. Then if a needle valve was installed prior the 3 pt the excess would have to be separately routed to sump to avoid relief valve opening.

PS: I just took time to look at the valves J_J posted which would I think accomplish what I stated.

 

[k0ua]

James aka k0ua
I'm a firm believer that information posted on the internet should be "accurate" not someones "opinion" especially on a tractor forum. I will not tell you to shut up. I'm getting a little long in the tooth but still not too old to learn. On most tractors I've been acquainted with the 3 pt control valve is the last valve to get hyd power. So please explain why the FEL control valve has 2 return ports(return & PBY) and how a needle restrictor valve will cause a relief valve to unseat? I think 2 return ports is to accommodate the excess flow of higher output hyd pumps. Older open center hyd systems only had one(1) return port(hose).
Thank you for your patience,Jim

I did not say that the relief valve would open, with a needle valve in the Power Beyond circuit heading toward the 3pt valve. It could I suppose if the needle valve was screwed down , but it would cause heating of the fluid as it would act as a restriction in the fluid flow and would cause a constant pressure in the system. Ok There are 7 hoses/ports in a typical modern FEL control the 4 work ports, the IN port from the pump the PB port and a Tank/sump port. With the valve centered the fluid flow in the IN port, and out the PB port. NONE of the fluid ever, ever flows out the Tank/Sump port unless you move the FEL control spool valve to allow a path for the fluid from the work ports on the opposite side of the cylinder to get back to the sump. Do we agree on this point?

 

[Fallon]

In a power beyond loop most of the time full pump flow goes to the in port on a valve, then to the out port & on to the next valve. When you divert flow from the loop to a work port it pushes on 1 end of the cylinder (the other end of the cylinder gets dumped to tank). The valve partially or completely blocks the power beyond loop, pressure in all of the power beyond loop up until that valve rises until the cylinder (or motor or whatever) moves. When pressure rises because the pump is always pumping & the cylinder stops moving (to much load or limits out) a pressure relief valve will pop open (usually in the first valve in the loop).

If you restrict the power beyond loop (needle valve in it), it will put more load on the pump & everything else in the system all the time. If you only had 1 valve in your power beyond loop & no restrictions on your tank line, you should be able to tie them together with no issues.

If you put a needle valve between the 3pt control valve & the cylinder it would restrict flow when using the 3pt control, but not otherwise impede the power beyond loop. That's what I'm planning on doing for my Top 'n Tilt cylinders so they are slow & easy to adjust precisely.

You may want be carefull taking my advice however... Apparently I can't tell the difference between 1/2" & 3/8" JIC fittings, which has wrecked havoc with my TnT project for the moment. :banghead:

If you tie together the power beyond out port to the tank port, fluid would just go to tank rather than the next valve in the loop. Also depending on restrictions & what not, fluid could push against the tank port on a valve/cylinder & cause it to have back pressure working against the other side of the cylinder.

 

[Fallon]

Let's discuss for the moment a tractor without a frt end end loader then if I'm thinking correctly there will be no PBY loop. Then if a needle valve was installed prior the 3 pt the excess would have to be separately routed to sump to avoid relief valve opening.

PS: I just took time to look at the valves J_J posted which would I think accomplish what I stated.

From what I understand all modern utility tractors use a power beyond loop. First stop would usually be the loader valve, last the 3pt valve. If have no loader or other valves, it just goes straight to the 3pt. To add a loader or other valve, you cut the line from the pump & put that to the In port on the new valve. The out port (not tank port) from the valve gets connected to the other side of the line you just cut so the fluid can cary on to the next valve in the system.

Restricting the flow of the power beyond loop is a bad thing, it puts load on the pump & heats the oil. However temporary restricting or blocking that loop is how every valve in the loop does it's job, so temporary restrictions obviously aren't a problem.

 

[k0ua]

From what I understand all modern utility tractors use a power beyond loop. First stop would usually be the loader valve, last the 3pt valve. If have no loader or other valves, it just goes straight to the 3pt. To add a loader or other valve, you cut the line from the pump & put that to the In port on the new valve. The out port (not tank port) from the valve gets connected to the other side of the line you just cut so the fluid can cary on to the next valve in the system.

Restricting the flow of the power beyond loop is a bad thing, it puts load on the pump & heats the oil. However temporary restricting or blocking that loop is how every valve in the loop does it's job, so temporary restrictions obviously aren't a problem.

We seem to be on the same page, now if we can get Jim to say "uncle" we will be done!

 

[Tx Jim]

k0ua
Ok I'll say "UNCLE". The modern PBY loop came into being after I left a JD dealership in the late 80's Thanks for enlightening me. Happy Thanksgiving to ALL.
Jim

 

[k0ua]

k0ua
Ok I'll say "UNCLE". The modern PBY loop came into being after I left a JD dealership in the late 80's Thanks for enlightening me. Happy Thanksgiving to ALL.
Jim

Happy Thanksgiving Jim.

 

[SSdoxie]

Let's take this thread back to OP,s original question & complaint.
KiotiLK35; If you think too much flow is causing the problem, try lifting same attachment at various engine RPM. Faster engine runs = more flow, slower engine speed is less flow.
I see in a related thread from about a year ago, you posted question in how to increase 3pt lift speed. If you were getting too much flow to cause the jerk it would not result in slow lift, but have too fast of lift. Did you change the pump to a higher volume pump?

You state having to move the position control lever more than half way (6 on scale of 10) before any lift occurs then it jumps into position. That tells me you have some oil by-pass in the lift control requiring flow has to get to a higher rate filling the voids in the by-pass until enough pressure in built up to open load check to the cylinder. This extra by-passing oil could account for the slow lift speed.

Not knowing how close the LK resembles the CK or DK models, take the seat off and look at the lift control right next to where the drop speed linkage hooks up. Is there a Allen screw with a jam nut on it? If so the LK has an MLS valve like the CK & DK. This MLS valve is the adjustable flow orifice (needle valve as discussed in previous comments here). Inside the MLS valve are some fixed orifices that allow oil flow to pressure sensing spools that need to shift to control when and how fast the lift cylinder operates. If the that adjustment screw is turned in too far the lift will operate quickly but will continue to plush (jump up and down) when raised and trying to hold at given height. If screw is turned out too far, it will require more oil to flow before starting too raise, then vey likely jump into position when the spools shift.
Hopefully the LK has the MLS valve, it is easily adjusted. Put an attachment on the 3pt (heaviest 1 you have), raise the 3pt up a little over 1/2 full height, leave running about 1/2 throttle, loosen the jam nut and start turning the screw in (clockwise) until the lift arms start to pulse up & down, turn screw back out until pulse stops then continue to turn screw out another 1/2 to 3/4 turns.

Please post back on if you do have the MLS valve and results: More information we can get regarding similarities to the CK or DK models, more help those that have these models can help out.

 

[KiotiLK35]

Thanks SSDoxie. Will check out the valve you describe on my tractor today and see if it has similar adjustment capability. Will let you know.