I picked up my 1989 NX125 early in February from a couple who was selling it on behalf of their elderly parents. The previous owner was an old man who has had this bike since it first rolled off the assembly line. He used it primarily as a trail bike and modified pieces of the bike: removed the front fairing, turn lights, and added a footrest near the front of the bike for his granddaughter to ride along with him. He could no longer ride it because of old age and the couple sold it to me for a mutually beneficial price.
It had been sitting for what appeared to be ages. After cleaning out the carb, replacing the spark plug, just the battery was left. I put the wires backwards on the battery and popped the fuse....why me? lol. [Ed: I've done this as well, in an effort to jump start the bike. I attached the jumper cables backwards and ZAP, goodbye fuse] At this point I was frustrated at the work I was doing and not seeing a bit of success, who else knows what this bike had wrong with it. I ran into NXDave’s blog and got to work on it after finding the resources page, where the shop manuals are.
After a short trip to wally world, I put in the 20A fuse into the battery relay, connected the battery, and the bike came alive! I put the choke on, and cracked the bike. It struggled but the starter turned over and stayed on, YES! I took it out for a spin to see what it can do. Top speed I got on it was about 52, [Ed: I've had mine up to 65 but I think that's max.] and it took a while to get there (I hate problems, but at least the bike runs now). I was expecting a little faster acceleration and a bit more at the top speed [Ed: this is the reason that I needed a few more CCs for my new commute]. I examined the engine oil and it was dark as night. I am currently on my way to changing to the oil and make some more adjustments to get this bike in peak shape. For right now it starts and runs well, I can keep up with any car on the streets here in Arkansas and get a nice MPG to boot.