KymcoForum.com

I would stick with Ethanol. The octane matters more than Ethanol or non-Ethanol. Higher octane in an engine that only needs the lower octane sometimes ends up with worse economy. Sometimes. The only fuel related issues I've ever had in any vehicle was with NON-Ethanol in a carbonated car engine... And switching to Ethanol fuel solved that particular problem. I did a test a LONG time ago in that same car going 30 days of a long distance commute using non-Ethanol and then 30 days of the very same driving in the very same temps and road conditions and speeds using only Ethanol. I found no difference in mpg! Some tanks of one were 2-3 mpg better and some tanks of the other were 2-3 mpg better. Mostly Interstate driving, same route and traffic both ways both times.

BTW- the fuel related issues were a frozen fuel line in below zeroF temps one time and a plugged fuel filter another time. Ethanol prevented the freezing and also cleaned out the gunk in the fuel lines and I never had a cleaner fuel filter after replacing it from the collected gunk that was cleaned out. Similar result for cleaning by switching from a paraffin based oil to a graphite based oil (paraffin left a wax deposit everywhere).

...

Later a passerby asked, looking it over, "Is that a Vespa?"

"Oh goodness....no! that kinda stuff can get a fellow beat up! It's Chinese!"

He was puzzled at my remark. He doesn't know Vespa owners.

...
Stig

And I thought you had a Kymco (Taiwanese)!

Don't know how much help this will be but this is the electrical diagram for what I believe is the 2020 Euro 4 version of the AK 550.
https://drive.google.com/file/d/1M48vAJRF57y060p1fRAHnw0bEhk3DBpd/view?usp=drive_link

I downloaded this document as well as the service manual from the Austrian Kymco HQ web page technical downloads page.
[url]https://kymco.at/kymco_store_view/dowloads/kymco.html]https://kymco.at/kymco_store_view/dowloads/kymco.html][url]https://kymco.at/kymco_store_view/dowloads/kymco.html[/url]
The AK 550 documents are more than half way down the list and include several documents including this electrical diagram and the service manual and others. The document names in the list are not English but the documents, when I downloaded them, are in English.

You should be able to download and open the diagram and then zoom in to be able to clearly read it.

Don't know why the previous owner didn't just unplug the ring... or collar as it is called in the parts list.
If you need to replace it to regain the lighting the collar is available on TBSS here:
https://taiwanbigscootershop.com/collections/ak550/products/kymco-original-parts-keyless-system-ak550?variant=39519530221667

Major bummer on the wheel damage. I used to take my wheels in to the dealer to have them swap the rubber on my Hondas and Suzuki bikes. I even took the front wheel of my AK to the Suzuki dealer to swap the rubber the first time and they did without issues. But I decided to start doing it myself to save some gas money. Not really so hard... other than the effort to get the new tire over the rim. Just get a good set of rim protectors and at least 3 tire spoons, or maybe 4 of them. I can see how easy it would be to damage the rims. I even have a slight scratch on my rear rim from a slipped rim protector but no real damage other than the paint/finish. I used balance beads when I did my own rear tire swap and it did work out nicely (other than that scratch). I have the balance beads for the front tire for when I swap that one next month.

I won't really NEED to swap the tire before my trip to N Tennessee but the front tire won't make it the entire trip so I'll swap it 1000 miles early for my 1300+ mile trip. I don't want to cut it that close for tire wear... especially pulling a little trailer. I'll likely be swapping the rear tire rubber in the next few months.

NOW, as of tonight, I am calling this project complete.
This afternoon I uninstalled the hitch frame from the bike and added vinyl electrical tape to the stainless tubing and bar where they contact the aluminum bike frame. I decided to just wrap the tape all the way from the front end to where the tubing exits the bike body just to make it one continuous wrap that terminates under the rear mounting bolt nylon washers to prevent the tape from unwrapping after some time. Then I reinstalled the 2 side tubes of the hitch frame and used thread lock on the nuts torquing those tight.

Then I removed the temporary nuts I had used on the receiver to bolt that to the end plate and added the nylon lock nuts that were provided by Uni-Go for the bolt kit for the receiver. I used thread lock on those also on the threaded part of the nuts. And then I also reinstalled the end plate using thread lock on those nuts as well.

After all parts of the hitch were installed and tight I replaced the storage box and installed all 6 bolts that hold it in. Up until now I had been only using 2 of the bolts to hold the storage box in place when I wanted/needed to ride the bike. Now the only time I'll need to remove the storage box is to do an annual inspection of the frames and attachment points inside... or to install some other farkle where I need access inside the body of the bike.

Here is what the parts inside the bike are like now.
https://photos.app.goo.gl/zFn6JcXPrK1ARFQo6

Was a very nice day today. Near 60F and sunny but VERY windy. 25+ mph constant wind with higher gusts. Only went for a short ride. 1.5 miles to go to the UPS office to return an Amazon item but forgot they closed 20 minutes before I got there. Then I took the long way home resulting in over 16 miles riding today. I pulled the trailer again for this ride only it was empty so I could see how it went with no load other than the weight of the trailer itself (70 lbs). The trailer bounced a bit more when going over bumps and bigger cracks in the road but otherwise stayed smooth rolling.

I did go for a little ride tonight pulling the trailer. Kept to slower roads. Started out on 25 mph roads for several blocks. Then stepped it up to 35 mph roads for several miles. Then I got it up to 45 mph for a few miles and then slowed back to 40 mph for most of the way home. I adjusted the left mirror down so I could see the trailer lid and the end of the LED brake bar just aft of the lid. That chrome LED bar told me a lot about how the trailer was tracking behind the bike. It was solid and stable behind the bike at the speeds I was going. Temps were just a little over 50F, sunny with 15 mph winds. I only rode about 14 miles.

I was told to expect this mono-wheel trailer to act like a passenger who was attempting to "help" me go around curves and turns leaning into them. So I was expecting that effect but was pleasantly surprised that the feeling was very slight. I could tell it was there but if I wasn't told about it I might have missed it. Having pulled pop-up campers before I knew what to expect with the performance of the bike. But all influences were VERY subdued compared with pulling a camper even with my current bike weighing so much less than those other bikes that were pulling those heavier camper trailers. I could tell it was back there... most of the time... as expected. Stopping on a level road was like stopping while going downhill without the trailer. Accelerating on a level road was like accelerating uphill without the trailer. Otherwise the performance was totally normal as it would be without a trailer. I did do a few hard stops and there was no dive or lifting of the rear. Any emergency stopping while turning is expected to be the same as with any trailer on a bike and should be avoided as much as possible. I count this first test as a success and proof of concept for the trailer hitch as built for this one trailer.

I am planning another test ride tomorrow (likely) or Saturday on some faster roads up to 70 mph. Maybe I'll bump it up to 75 while out there just to see what happens. My wife told me she would follow me to watch what the trailer is doing from that vantage point. I know some owners of this trailer have taken it up over a ton, but that's not me. I likely won't be riding past 75 mph with the trailer in tow. Besides, the tire speed rating is "L" which is 75 mph.

Put it all together today. Temps in the garage were just barely 50F but I put on an extra sweatshirt and went to work. I torqued the bolts on the receiver to a tight 3 finger mechanics tightness... actually 4 fingers tight with my hand close to the ratchet head. Then I installed the square tubes on each side. There was a bit more adjusting to do with the flat bar on the ends of the square tubes to be tight and flush with the spacers AND the bike frame. The bolts to the bike frame were also torqued same as the receiver bolts. Since these nuts and bolts are a metric 10.9 grade hardness I could tighten them even just a little more without worry of them being over torqued.

Then came time to mount the end plate on the ends of the square tubes. The holes at the ends of the tubes were not perfectly aligned so I inserted my round file in my drill and filed them a bit to enable the bolts to be pushed in without too much pulling in on the tubing ends. There is still barely a little stress on the tubing ends pulling them inward just slightly. Since the end angles of the tubing was about 1 to 1.5 deg off I added a washer to the bottom bolts between the end plate and the square tube ends. When all the bolts were tightened I put a vertical level on the end plate and found it was less than 1 deg forward at the top. This is where I wanted it to be since that will level out with a little extra sag on the rear of the bike when loaded in the storage box and in the trailer. I will leave the extra length of the bolts alone for now since the long receiver bolts are behind the mud flap. The end plate bolts are well outside the rear tire so no worries there.

In the picture where the trailer is hitched to the bike I put a board under the rear wheel same as is under the front wheel of the bike to level it. That shows close to how the trailer will sit behind the bike. I'm sure a little more sag in the rear suspension will have the front of the trailer down just a little but it looks like I might not have to adjust the trailer tongue down any. I have the receiver 2 inches lower than the original owner had it. Will see when I have a test load in it. Also in that picture the single safety chain (all that is needed for this type of trailer) is just hanging. I am waiting for a special threaded quick link that will be used to hook the safety chain to the receiver. While the trailer was hooked up and the electrical harness plugged in I tested all the lights and everything works as expected.

With all the bolts tight I grabbed the end plate of the hitch and wiggled it up and down, left and right, forward and back as hard as I dared. This hitch as it is so far, without the hanger bar, is the strongest stiffest sturdiest hitch I've had on any bike... maybe my old Gold Wing hitch was about the same but that one was bolted directly to the frame under the saddle bags. Other hitches, like on the ST1100, had more wiggle than the hitch I just installed on the AK. I could wiggle the entire bike but the hitch itself did not wiggle at all separately from the entire bike. The bike and hitch frames are one unit. I really don't think any way of adding a hanger bar will make any difference in the sturdiness of this hitch.

The next thing I plan to do is to put some load in the trailer and in the storage box on the bike and go for a few test rides so check how it tracks behind the bike. Once that is done, if all goes well, I will be removing the hitch parts again and cover all the parts with a rubberized coating. Then I'll install the hitch frame permanently.

https://photos.app.goo.gl/qFYFNSExMpwee3278