I mentioned previously that I was a little dismayed to discover that there is no factory tachometer on the NX's dash. I decided to procure a digital tachometer (and hour-o-meter) from Trail Tech. For just under $40 (incl. shipping), I now have a tach for the bike. The tach is powered by an internal battery which is supposed to last for about 10 years. Additionally, it displays the hours the engine has been running when the engine is turned off. While I prefer an analog tach, this is about as affordable as it can get. I prefer analog simply because it can be glanced it and your mind will register (approximately) what revolutions the engine is turning, based on the location of the needle in relation to the tach face. With digital, your mind has to see the numbers and then 'convert' said numbers. It similar to switching from an analog to digital wrist watch.
I wrapped the red wire tightly and secured it with some electrical tape and another zip tie. I used additional zip ties to hold the tach wire to the throttle/choke cables. When the throttle cable branches off, the tach wire continues to follow the choke cable where it goes thru the dashboard and the extra wire is contained within the cover.
Finished and ready to go!
Addendum: I forgot to mention that, with a little help, I finally discerned the red line for the Honda 125cc four stroke SOHC engine; it's 10,500 rpm (!). Maximum horsepower is made @ 10,000 rpm. I don't know about you but my ear isn't good enough to "hear" that red line, hence the need for a tach.