Kx121-3ss thumb power

[NikonRon]

There's no lever at or near the hydraulic tank. Ron

 

[dfkrug]

Just for reference I have a KX91 and if I clamp down with the thumb then let off it continues
to hold and does no back off.

Is that the way Kubota generally does it with OEM thumb control on mini-Xes?

My only experience with OEM hyd thumbs on a Mini-X is with a Takeuchi. In that case, there
was a foot pedal which closed the thumb when you pushed it, and retracted the thumb when
the pedal was released.

If the OEM hyd thumb can be pushed back, while stationary, with bucket force, there is also
a "work port RV" on the valve. In addition to some sort of system RV.

 

[NikonRon]

I don't know that it actually backs off, I just don't think that it is applying enough force to hold a load. The Kubota has a thumb operated push button with push to close and push to open. Ron

 

[Code54]

How old is the 121? All the newer machines have a level that lets you switch the flow for breakers or a thumb. See attachment to give you a better idea.

Yes - the factory sets the thumb system up so the bucket can "push" it back - lets you curl and grab better. My 91 will grab a 4x4 and snap it right in half before the bucket ever pushes the thumbs back. It has a LOT of clamping force. While learning the machine it was not uncommon to break rocks by squeezing them too tightly - had to learn a light touch.

 

[NikonRon]

2009 model. Ron

 

[Code54]

I also think you can select flow through the joystick/service port setting. Not sure if that would have anything to do with it but may want to check your book. It looks like an 09 should have a selector lever near the tank. This manual shows it and it is a 2007. My 2015 is still the same setup.
Hope it helps

 

[NikonRon]

Come daylight I'll have to look again, thanks. That looks to be just a ball valve in the circuit. Ron

 

[Code54]

Basically is - Mine got a shade out off position one time and my thumb started to act very weird. I have a zip tie on mine so it cant change position, think the jarring around let it move a shade. Good luck!