Importing and modifying a new mini excavator from China

[dfkrug]

Only a 10hp? The unit must be pretty small. I would be thinking a Kubota or Yanmar
in the 23hp range.

This mini-X is Really Small, just like the Kubota K008. There are dozens of makers of excavators,
and thousands have been made big-and-small, especially after the mid-90s. It is surprising to me
that EPA rules for tiny diesels (SORE) have made it so restrictive that makers are abandoning them.
It also seems that 700+cc in a Yanmar or Kubota 3-cyl should put out more than 10hp. The bigger-
is-better crowd is not going to like this machine. But the owner that needs to squeeze into a tight
backyard or inside a building will see the advantages. Hauling one is also possible in the bed of a
large PU.

But back to my XN08. Since I received my unit partially disassembled for shipment, I did not fully assemble it
until I finished all my mods and testing. Complete pix and 5 videos on my Utube page will be linked at the
end of this thread.

My seller provided accessories and spares at what seems like their cost. In the pix I show a larger bucket, a
ripper tooth, a mechanically-linked grapple, spare filters, and even a toolkit and box. The toolkit contains a complete
set of open-end wrenches 8-30mm and even a grease gun with needle tip. You can see the main spool valve
spare that I traded for my missing engine. It actually costs a bit more than the ChangChai engine. I got 2 spare
bucket cyls at only $50 each, for example. The standard bucket comes with bolt-on teeth. A mechanical thumb is
standard, tho I will use the AUX valve to power a hyd thumb that I plan to make later.

Some nice features of this machine are the steel canopy with integrated rollbar. The main body sheet metal is
2mm (.075") and is quite substantial. The joystick rods and finish screws are stainless steel. All cylinders seem
to have replaceable sleeve bearing inserts. Some of the pins have threaded ends with nylock nuts.

 

[majorwager]

Are the you tube videos available now?

 

[dfkrug]

I went with a Chinese Honda-clone single cyl gas engine with electric start. Some call
these Chondas, tho makers in China have taken the Honda GX390 design up to 420 and 440cc.
Some of the genuine Honda engines are now made in China.

Like the mini-X, there are many factories in China making this engine. Mine is made by
Chongqing Dajang Power Equipment Co and imported by a company in SoCal, which calls it
Duramax. It is identical in all the ways I can see, other than paint, to the HarborFright
Predator 420. Note that HF has a hemi version of this OHV engine for the same price with
a bit more low-end torque. The Duramax 16hp cost me $330 delivered, incl tax, about $50 less
than HF. That's about 1/3 the price of a Honda GX390. Duramax has a 440cc engine, but
it runs $500....maybe that one has pressure-lube?

I have had and repaired a number of these Chonda engines, and was usually disappointed
in how well they are made. That is improving, however. Sediment in the bottom of the
fuel tank and worn out pull-starters are weak points. Mine arrived missing the shaft
key, but one was sent to me right away.

 

[dfkrug]

Are the you tube videos available now?

Anyone who wants to jump ahead can go to my Utube page:


walkaround after most mods installed:
XN8 walkaround Small - YouTube

startup testing:
XN8 initial startup - YouTube

pressure test:
XN8 mini-excavator pressure test - YouTube

testing the log grapple:
XN8 log grapple on mini-X - YouTube

first digging test using larger bucket with new welded-on teeth:
XN8 digging - YouTube

More explanations will be forthcoming.

 

[TractorGuy]

I went with a Chinese Honda-clone single cyl gas engine with electric start. Some call
these Chondas, tho makers in China have taken the Honda GX390 design up to 420 and 440cc.
Some of the genuine Honda engines are now made in China.

Like the mini-X, there are many factories in China making this engine. Mine is made by
Chongqing Dajang Power Equipment Co and imported by a company in SoCal, which calls it
Duramax. It is identical in all the ways I can see, other than paint, to the HarborFright
Predator 420. Note that HF has a hemi version of this OHV engine for the same price with
a bit more low-end torque. The Duramax 16hp cost me $330 delivered, incl tax, about $50 less
than HF. That's about 1/3 the price of a Honda GX390. Duramax has a 440cc engine, but
it runs $500....maybe that one has pressure-lube?

I have had and repaired a number of these Chonda engines, and was usually disappointed
in how well they are made. That is improving, however. Sediment in the bottom of the
fuel tank and worn out pull-starters are weak points. Mine arrived missing the shaft
key, but one was sent to me right away.

I bought one of the DuroMax generators off ebay last year. It came with the 18HP dual fuel engine. My daughter has it and has not used it yet so I have my fingers crossed it will work. I test ran it on both propane and gas under a load and it would run continuous at 8KW with either. Applied the max 10KW it was rated for and it fell on it's face.

 

[dfkrug]

I bought one of the DuroMax generators off ebay last year. It came with the 18HP dual fuel engine. My daughter has it and has not used it yet so I have my fingers crossed it will work. I test ran it on both propane and gas under a load and it would run continuous at 8KW with either. Applied the max 10KW it was rated for and it fell on it's face.

That is the 440cc engine, about the biggest thumper you can get for small equipment. Does it have
an oil pump for lubrication? I recently killed my Chinese Generac inverter genny when I tried to start my
reefer. Not repairable. :-(

 

[dfkrug]

These are the modifications that I did to get my machine going:

Modifications:
-- ChangChai diesel engine replaced with CARB/EPA-certified 420cc DuroMax 16hp gasoline engine
-- hydraulic pump relocated from right side to left
-- engine cooling fan duct moved to right side from left
-- diesel fuel tank removed
-- spin-on hydraulic fluid filter added on return line to tank
-- needle grease fittings replaced with zerks
-- small electric fan added to left side of house
-- hydraulic oil temperature gauge installed
-- carburetor air inlet ducted to outside of house
-- electrical wiring redone to add engine OFF function
-- controls changed from excavator-style to backhoe-style

The photos show the diesel engine installed in another unit. Note the rubber air
duct that routes the cooling fan air in from the outside of the house. The duct
replaces the pull-start assembly. You can also see a hydraulic oil cooler, which
my unit does not have. I wish it did, and I may add one later.

 

[majorwager]

Purchased my hydraulic oil cooler from a firm in California.

 

[dfkrug]

Purchased my hydraulic oil cooler from a firm in California.

Did you also use the fan? I will bet that one takes several amps to run.

The DuroMax 420cc engine has an alternator to charge the battery, but little else. It puts out about
650mA at mid-speed, and about 700mA at higher RPM. The LED worklight takes 600mA. The small
120mm electric fan I installed uses 350mA. Actual measurements with an ammeter.

 

[dfkrug]

In prepping for my new engine, I removed the diesel fuel tank. It features a spin-on
filtration system and very nice sight glass to monitor fuel level. The walls of the tank
seem to be 4mm steel. The fill tube is also steel. There is even a brass petcock to
turn off this gravity-fed system. Nicely made. Too bad it has to go, due to space
constraints.