I'm new to the forum (second post!) but I wanted to share what I've learned and what I've done to my K-Pipe.
The first thing I did when I got it home was remove all the EPA mandated crapola. While this didn't lighten the bike up all that much or improve it's performance it definitely greatly simplified it and improved it's appearance. The engine and fuel tank now breath to the atmosphere.
During the break-in process I studied the bike and it's carburetor. Unfortunately it's another EPA mandated goodie that doesn't allow you to adjust the mixture screw or the carb needle. After discovering this I installed a Mikuni ($40 from eBay) that I've run on my other horizontal motor bikes removing the extremely restrictive air box in the process. It now breaths through a K & N although I may end up running a foam element on it. I also matched the intake manifold to the new carb which required a tiny bit of aluminum to be removed, maybe ten minutes' work. The jetting is still a work in progress but it's close. Going with this carb eliminated the cable operated choke.
I saw the Delkevic mufflers on eBay but didn't want to drop that much money especially if I found I couldn't live with the noise. As a cheap alternative I bought a pit bike muffler ($20 delivered!), shimmed it with a piece of thin wall aluminum pipe and installed it using a home made aluminum bracket. I rode it around the block and found it screamed "LOOK AT ME!!!" so it came back off. As I plan to ride the bike long distances I just don't think I can live with the noise.
As mentioned on my other post in another thread I recently installed the heel/toe shifter that originally came on the bike, doing away with the linkage. It now shifts backwards from every other new bike in American other than those set up for road racing. That's a big adjustment for me especially when riding my other bikes but it shifts so much better the linkage isn't going back on. Maybe KYMCO reversed the pattern on the 2017 K-Pipes with a different shift drum but so far no one seems to know. If anyone does please let me know.
I hate the phony blinkers in the tank covers and thought about ordering up OEM units for the non-U. S. models to replace them until I saw the price. Right now the whole cover/phony light assemblies are off the bike and other than the wiring hanging down really doesn't look all that bad. I'm not sure what I'll do to replace them if I leave them off but the bike is a lot narrower without them.
The stock handlebars were terrible to me with way, way too much sweep back. I ended up swapping them to a set of generic Honda TRX-450 ATV bars that are a lot more comfortable.
The seat is terrible to my tender bum, too and for now an Airhawk pillon pad is strapped on it. Eventually the seat will make it's way to Sargent for a redo.
Overall I really like the bike. The hybrid manual/automatic clutch setup is wonderful and after several years of riding hot rod step throughs with kickstart motors having an electric starter is like dying and going to heaven. It's a lot heavier than my step thorughs--around 238 lbs. wet as it is right now--but there again it has mag wheels, wider tires and a disc brake, something they also lack.
The blinkers are terrible. When you go to change a bulb you'll see what I mean. I bought a set of Honda XR-L replica blinkers which while bigger and ugly are stone reliable and will accept auto parts store bulbs unlike the expensive and hard to find bulbs that came in the stockers.
One other thing I learned was that this bike uses a DC powered CDI unlike most of the other horizontal motors that use AC powered units. I experimented with several DC units I found on eBay without any noticeable improvement. Keep this in mind if you go to hot rod the bike and get tempted to try one of the many units available for the pit bike market.
I'm really glad to have found someplace where I can share information about these bikes. They're not selling all that well around here and I've never seen another one yet.
Oh yeah--I have a link to a shop manual, too. Holler if you'd like to have one for yourself.