Importing and modifying a new mini excavator from China

[dfkrug]

Clearance issues. They are used where zerts would get knocked off.

As far as I can see, that is the only legitimate use for these fittings.

Notice in my Post #67, first photo, that there is no way to get even a needle-grease gun in there. What
were they thinking?

Oscar Zerk should have won some sort of prize.

 

[dfkrug]

As mentioned above, I traded an extra stack valve for my missing engine. The
engine has a list price of a bit less than the stack.

When it did not work initially, I opened up my spare to see what was going on. That
was when I figured out where the IN and OUT were, and they were connected backwards.

You can see the load-check valve, which I removed for the photo. Plumbed backwards,
no flow would go to the tank when expected.

The spool looks good, with ramps on the lands to assist with feathering, or gradual flow
changes. Nice.

My AUX valve section (shown) I took apart to see what it would take to convert it from
detented to spring-centered. I have ordered those parts, but have not received them yet.
The change over looks easy. I definitely do NOT want a detented valve for the hydraulic
thumb I will add later.

 

[bindian]

As far as I can see, that is the only legitimate use for these fittings.

Notice in my Post #67, first photo, that there is no way to get even a needle-grease gun in there. What
were they thinking?

Oscar Zerk should have won some sort of prize.

At work, we have zert fitting grease gun fittings that will slide on, 90 Degrees to the zert. One side is cut out. You only need about a 1/4 inch to push on. It doesn't lock as good as a zert coupler, but does the job.
We also have 90 degree flush adapters when a straight one won't work.

I'll try to remember to take a photo of it tonight.
hugs, Brandi

 

[bindian]

Here is the 90 degree zert coupler I use at work and sometimes on my Mahindra's steering cylinder zert.

Also the 90 with various needle fitting adapters.
hugs, Brandi

 

[dfkrug]

Also the 90 with various needle fitting adapters.View attachment 567012

So those 90-degree needle fittings for your grease gun require some tool to apply pressure at
the head so grease gets injected. Looks difficult. Thx for posting, Brandi.

 

[dfkrug]

A few more comments on the electrical system:

A small car-sized 45Ah battery resides below the floor. It is somewhat accessible thru
a hatch, but the battery is larger than the opening, so the side panel must be removed
for replacement.

I had to redo the electrical system to provide a way to kill the gas engine. Small gas
engines are usually shut off by grounding out the ignition. Diesels are killed by shutting
off the fuel, in this case, mechanically. I also needed to provide switchable power so the
hour meter works and the work light is enabled only when ON.

The XN08 starter switch is better than the ignition switch from the gas engine, and it
provided an unused connection to kill the engine. Nice. I scribbled up a new schematic.

The boom-mounted LED worklight is a nice feature and quite bright. It consumes only
about 600mA, which is slightly less than the gas engine's alternator output.

 

[bindian]

So those 90-degree needle fittings for your grease gun require some tool to apply pressure at
the head so grease gets injected. Looks difficult. Thx for posting, Brandi.

The 90 degree needle fittings won't grease at all if there is any resistance. You have to hold pressure with your free hand to get grease in. Then, there is that squirt your face factor increasing
hugs, Brandi

 

[dfkrug]

Before I got to using the mini-X, I installed the larger bucket and removed the mechanical
thumb. There were no teeth on this optional bucket, so I made and installed my own.

I thoroughly dislike the soft cast steel teeth that often come on low-priced equipment. They
are just too dull, and don't hold a point or edge. Years ago I tossed my cast teeth that
came with my Bulgarian backhoe and made up weld-on tooth holders. Then I used crimp-on
replaceable teeth with very tough steel cutting edges. Works well, but I have never
replaced the teeth.

So this time, why not just directly weld on some tough steel teeth? No tooth holders at
all. If I wear them out, then I will cut 'em off and weld on new ones.

So here I am, cutting some teeth out of a rake tine. The tine was about $10, new, from
Agrisupply. The bucket photo is after my first test dig. I will see how they hold up.

 

[dfkrug]

Almost done!

I tossed the gas engine's OEM muffler so I could reroute the exhaust out the back panel thru
the original exhaust port. I tried to modify the exhaust manifold by cutting and welding,
but I was unsuccessful welding it. So I made a new one from plate and pipe, terminating
with a 1" NPT nipple. A new small engine muffler screws right onto that. I may add some
exhaust pipe tape at a later date to route even more heat out the back.

For the air intake, I cut a port in the plastic filter cover, sealed up the bottom holes, and
made up a foam attachment that makes the combustion air come in thru the grille
on the back cover. You can see the results in my 5th video.

 

[dfkrug]

So here is where I cap things off with the videos I posted on my Utube channel.

A few notes on using this mini-X: with 2400psi and 3" cyls, this machine can
really pull itself around, even with the dozer blade dug in. The hyd pump is more
than big enough to generate decent flow even at 2500RPM or so. The only
thing that is slow is the drive speed. The wheel motors are enormous.

Getting the oil too hot by running long periods on hot days will be an issue. An
oil cooler would be a great upgrade. Larger units from China seem to provide
coolers and better filtration. Both are necessary for this machine to last.

I have not tried out the track adjustment. It is mechanical, not hydraulic like you
see on name-brand excavators. Larger Chinese units do have hydraulic adjustment.

These small Honda-clone engines have no oil filtration (even on Hondas), so frequent
oil changes are a good idea. I plan to install a drain valve to make this easier. The
engine runs great, tho it generates some sympathetic vibrations that cause rattling
at idle. I will install padding to fix this next time I have the rear panel off.




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

 

[BigBlue1]

If the track tension is manual why is there a sticker that says "track tension device hydraulic cylinder pressure is high..."?

Rob

 

[dfkrug]

If the track tension is manual why is there a sticker that says "track tension device hydraulic cylinder pressure is high..."?

Yes, that and other labels make no sense. Larger machines from this machine's maker seem to have hydraulic adjusters.

 

[dfkrug]

To wrap this up, one might ask: what do buyers get for their $6500 or so, versus their $23K for an equivalent-sized mini-X from a known brand?

It is no secret that I am a fan of equipment from Kubota, so let me go back to the popular K008 excavator for comparison. There are 3 major features that make the XN08 far less expensive to make and sell: The K008 has hydraulically-adjustable track width, a side-swinging boom, and a TIER IV emissions-compliant 3-cyl diesel engine. In my opinion, not having these 3 features does not limit the XN08 capabilities in a significant way. And the lower price is very attractive.

Larger mini excavators from this same Chinese maker (e.g. the XN18) will have all these Kubota features and still be substantially less than the equivalent Kubota. They use Yanmar 3-cyl diesels, but I do not know their EPA status.

BTW, the quotation for the K008 includes an optional 16" bucket, which is $700. For the XN08, you will be more likely to pay $100-120.

In the future, I hope to add to this thread with other mods (hyd. thumb), repairs, and in-use experience notes. I invite any factory in China which makes these machines to copy at will anything I have done to make them more sellable in the US. Turnkey.

 

[dfkrug]

I meant to add that the efforts to modify this machine took less time than the importation process, and it was less aggravating. I did dodge one bullet: there is now a 25% tariff on this category of import from China (HS code 8429). I hope that does not last.

 

[California]

Earlier you mentioned you changed the controls from default excavator to backhoe configuration. Could you explain the difference? Thanks.

 

[Kyle_in_Tex]

Great thread!

 

[MossRoad]

Earlier you mentioned you changed the controls from default excavator to backhoe configuration. Could you explain the difference? Thanks.

There's two different standard configurations for the joysticks and what functions they control.

 

[ada loongsheen]

Dear David
This should be a great work
Very kind of you to share with us the the whole process .
That will do me a great help .
Thanks

 

[California]

There's two different standard configurations for the joysticks and what functions they control.
View attachment 567752

Moss thanks.

 

[dfkrug]

Earlier you mentioned you changed the controls from default excavator to backhoe configuration. Could you explain the difference? Thanks.

MOSS has it, with a nice diagram.

ISO is what is sometimes referred to as "backhoe" style, while the SAE pattern is for excavators. I have many hours on my backhoe, and there is no way that I am gonna have 2 different configurations here. Note that excavators sometimes have a boom swing as well as a house rotation action. The simple XN08 has only the house spin, so I am using the swing function for that.

The change is easy: just swap 4 hoses. Some other machines even have a selector valve to make this change by just flipping a lever.