Sorry for the lack of posting recently. Not much has been happening with the NX and I'm on a big push to get the TransAlp re-assembled before it gets too late in the riding season. With any luck, I plan to get the factory rear rack on the NX in the next few weekends, time permitting.
I have recently noticed that the NX doesn't require as much carburetor enrichment as I previously thought. First, let's revisit my old Reflex (TLR200) which was exceptionally cold-blooded. Not only did it require choke, to start, but took forever to warm up. In retrospect, it need some attention but I never figured that out. The NX doesn't seem to require that much choke, to start, nor does it require it for very long. I only apply about 50% choke to start the engine. It will immediately idle at about 1000 rpm. That's a little low so I usually assist, with throttle application, so that the rpm reaches ~1700. It will only take about half a minute and I'll hear the engine note increase and the rpm will also increase to about 2000 rpm. At this point, I'll reduce the choke to about 30% and repeat the procedure. Once I reduce the choke again, the NX is ready to go. By the time I reach the main road (about three blocks distance, inside my housing development), I can reduce the choke once again (so that it's now at about 10%). When I accelerate onto the main road, engine response is pretty crisp. Previously, I would encounter some bog (rich) which would take about 1/2 mile to clear out after reducing the choke by quite a bit. Since traffic moves briskly on this road, I need to have the NX running properly (or risk being "consumed" by rush-hour traffic). By the time I'm two miles from home, I can fully remove any choke and the engine will be idling @ 1340 rpm (+/- 50 rpm).
Of course this is all predicated on ambient temperature. In the morning, temperatures are now about 60º F. Daytime highs are at about 80º F. I have a heated garage so the NX's engine should never be colder than 55º F, in the morning. Afternoons will be a different story as we get into Autumn, especially late Autumn. Since the power-plant is relatively small, I'll be curious as to how quickly it warms when temps are in the 30º-40º F range. Naturally, more choke will be needed but for how much and how long will be the key. I'd prefer to avoid rich conditions (fouled spark plugs) so that I don't have to encounter tailgaters.