Friday, August 26, 2011

Choke, the finer points of

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.

1 comment:

  1. i ride a 1988 nx125 in north nevada and have found that full choke to start up and half choke after 10 sec. and then ride for 1/16 mile turn off choke and it is fine rest of the day same weather cold or warm, this engine has 14000 miles on it and sat for over ten years engine would not turn over when i got it but with a little work it broke free and runs very well average about 45 to 50 mph.