Importing and modifying a new mini excavator from China

[MattB4]

I have detected no constriction orifice fittings on any circuit of my Rhino (Xiniu) mini. However, that does not mean that no maker has installed them.

I do find that the work circuit for my AUX feature does have more restriction to flow than the others. I run a hydraulic thumb with fairly small diameter hoses. The Oking units had a larger hose fitting for the AUX.

A restrictor in the boom down circuit may reduce jerkiness a bit, but check to see if you have one. You will have to open the console to access the stack valve, which you will have to do anyway if you want to change the control pattern.

It could be a restrictor since the boom does not drop when operating the the lever with engine off. When I get some time to remove all the covers I'll see if I can figure it out. Though my knowledge of hydraulic controls is fairly sparse. Just enough to replace hoses and valves if I can find the correct ones.

 

[dfkrug]

It could be a restrictor since the boom does not drop when operating the the lever with engine off.

That's a surprise. Of all the units I have seen internally, only the units with servo controls have the solenoid shut-off valve for the boom/dipper/bkt. Does your unit have servos? If you don't, something is amiss in the boom-down work circuit.

It is possible that there is a solenoid shut-off or diverter even if you have no servos. It is a good safety device to have, tho easier to implement if you have servos.

This is why one of the first things new owners need to do it to figure out how their mini's hydraulics work.

 

[MattB4]

... If you don't, something is amiss in the boom-down work circuit.

...

The issue seems to have gone away once I opened things up. The boom now drops easier and also drops when the engine is off and the control lever is pushed. I can only surmised that I had an issue with insufficient bleed off of trapped air in the cylinder and lines.

 

[Colby16]

Hi, I am a noob here. I found this forum while doing a google search. I just picked up a Diggit EM15 yesterday, from a local guy. I played around with it today and find some operations pretty jerky. The boom lift/lower, bucket curl and driving are where I feel it most. Is there anything I can do to reduce the jerky motion of these operations? It is worse at higher RPMs, but still can do it at lower RPMs. I see a lot of discussion on mini x's and being jerky in the discussion threads, but didn't see a what I would call a solution for an EM15. I am certainly new to excavators, as this is the first I have owned.

Does anyone have a owners manual for the EM15? Mine didn't have one when I picked it up and so far I haven't been able to find one online. The seller is suppose to get one, but not sure how long that will take.

Thanks

Here is photo of the new mini, the top was not attached when I trailered it home, I haven't installed it yet.

 

[dfkrug]

I see a lot of discussion on mini x's and being jerky in the discussion threads, but didn't see a what I would call a solution for an EM15.

I see a lot of discussion on mini x's and being jerky in the discussion threads, but didn't see a what I would call a solution for an EM15.

Welcome to TBN. Put your location (state, province, or country) in your profile and we will know where you are.

Jerkiness is a feature of super-light machines. Low weight + fast hydraulics = jerky. This is discussed above, yes, but simply put, these small Chinese excavators use pumps designed to run slower with diesel engines, and the move to gasoline units with faster RPM was not well thought out.

 

[Colby16]

Welcome to TBN. Put your location (state, province, or country) in your profile and we will know where you are.

Jerkiness is a feature of super-light machines. Low weight + fast hydraulics = jerky. This is discussed above, yes, but simply put, these small Chinese excavators use pumps designed to run slower with diesel engines, and the move to gasoline units with faster RPM was not well thought out.

Thanks,

Is there a way to adjust the hydraulics or reduce the flow? Or can the pump be changed out to help reduce it some? Or is this something you get better at controlling over more use? I have maybe 30-40 minutes of operation time at this point. I can fill the bucket quickly and rotate the cab to empty quickly, but I am losing half the bucket in doing so. Any tips?

 

[ptsg]

Wondering if it has the same issue that other poster here had, where the pilot pressure was set too high causing the controls to be hard to master.

 

[dfkrug]

Thanks,

Is there a way to adjust the hydraulics or reduce the flow? Or can the pump be changed out to help reduce it some? Or is this something you get better at controlling over more use? I have maybe 30-40 minutes of operation time at this point. I can fill the bucket quickly and rotate the cab to empty quickly, but I am losing half the bucket in doing so. Any tips?

Discussed above in more detail.

I bought a smaller pump, which would work on any of the non-servo-controlled units. I have not installed it, as I have been able to control most, not all, of the jerkiness with practice (150 hours or so now). I went from 6.8 to 5.5 cc.

The Diggit (see my above pix) has a larger pump that supplies oil to both the servos and the main valve, thru a flow divider. You could also reduce the size of that pump, but no one has yet found out the size.

As with the EM15 I worked on, your main valve RV is prob set too low, and the servo RV could be off as well. No spec to be found on the latter.

 

[bindian]

Dave,
Wouldn't a larger hose slow the jerkiness down some? I know it would slow the speed of motion down.
hugs, Brandi

 

[dfkrug]

Dave,
Wouldn't a larger hose slow the jerkiness down some? I know it would slow the speed of motion down.
hugs, Brandi

Smaller diameter hoses cause restrictions to flow, which slow things down a bit, but add heat. They act like a restriction orifice.

Most of the hoses on the units I have seen are about 10-18mm.

Pump flow is only 5-6GPM.