I mentioned I would do a write up for others that might find it helpful so here it is. You'll need to click on the pics to see the entire image. I don't know for sure, but the other 1400 variants may get similar bracing under the fender too.
The fender has to be removed. The electrical plugs for the turn signals and license plate light get unplugged near the back of the fender. The tail light plug is on top right to the battery on the left. Turn signal wiring needs unhooked from under the fender. Tail light wiring can remain attached to the fender. Once the the turn signal assembly is off, there is an allen screw up in there and another part way up. Those both need removed. The three points that attach the grab rail also hold the front of the fender in place. Once the rail comes off, gather the three stepped washers so you don't misplace them. The fender sort of clips to the side pieces that go behind the shocks. You can easily reach in and sort of pop the tabs loose. The fender can now come off. The frame support for the fender will need to be removed now. One bolt was already removed with the grab rail. The two small ones on the side get removed and you set that aside for now. More on that later.
There are quite a lot of parts that get put together for the supports. Here is most of the left side set:
In this pic, I have the left side laid out as it is oriented on the bike. The piece with the slash cut wedges inside the frame tube. The longer piece to the left extends down to another support point further forward. The bushing that you see is used if you do not have a pannier bracket. In my case, the rear mounting of the panniers replaced those bushings.
Back to the bike, there are plastic covers over the end of the frame tubes that need to be cut off flush:
And here is the end of the frame tube now exposed:
This is where the slash cut piece plugs into the frame, hence the need for the plastic shroud to NOT be sticking past the end of the tube. The reason the rear fender support has to be removed is because the bolt head will interfere with sliding the wedge into the tube.
So here are the brackets installed on the right side. Note that everything has to be loose until everything is started. You can see where the rear pannier bracket mount is sandwiched in on that special bolt in the back:
If you have a support bracket for a side bag that fits there, be sure you have reattached the fender brace before you do the special bolt. Now, with everything loose, you can rotate the angle bracket down and put a bolt up into that special bolt and through the angle bracket. The smaller strut headed off to the front also needs to be attached at both ends before anything gets tightened. In my case, that also included the front pannier mount that also attaches to the same mounting point. All this was kind of a pain getting it all started and not cross threaded. One everything is started, it can all get tightened down. If something is not lining up, something is wrong.
The bolt that goes up from the bottom will come out as it supports the bracket that extends out to the rear of the rack:
This is the only piece you will see after the fender is reinstalled.
At this point, I thought it would be wise to dry fit the rack to make sure everything lined up:
Time to reinstall the fender and reconnect the wiring.
It is worth noting that you can get to those bottom bolts, the forward of which is a nut and bolt, once the fender is installed. I did end up needing to loosen them up to get those side brackets bolted up.
After that,I rehung the panniers and mounted the top box, which I presented pics in another thread of the completed job. Hopefully, if another Eldo owner, (or friend of), decides to do this it may help knowing what to expect. As you can see, the rear rack is very well supported.