JN

The number of clip stages for JN jet needles is listed as #1 = 1st stage from the top. The top is the end where you attach the clip. It also includes taper angle and cut-up. The tapered side is on the bottom. The part number is different for large body and small body.

FCR Tuning - Should the Slow Jet Be Changed According to the Season?...

Tuning the FCR requires adjustments based on the weight of air and fuel. As the temperature drops, the density of the air increases, making the air heavier. In response, it is necessary to either increase the weight (amount) of the fuel or reduce the amount of air.

FCR Tuning - When changing the straight diameter of the jet needle, also adjust the clip position....

When you change the straight diameter of the jet needle, you may need to change the clip position as well, or else the performance can become quite poor. It’s difficult to specify exactly how many steps you should change the straight diameter before adjusting the clip position, but it seems reasonable to think that changing the straight diameter by about five steps would correspond to a change of approximately one clip position.

FCR Tuning - To what extent does the main jet affect the throttle opening range? - 2023-09-19...

I'm describing the effects of changing the main jet, focusing on how it influences throttle positions other than full throttle. After changing the main jet, I went for a test run. My assessment is centered around the changes observed from around half-throttle to three-quarters throttle rather than focusing solely on the full throttle range.

FCR Tuning - Adjusting Accelerator Pump Discharge Timing and Straight - 2023-09-12...

I’m framing this as fine-tuning rather than tuning in the strictest sense. The tuning of the FCR is the result of repeated A/B testing. It’s a process of searching for jets that improve performance, and then finding even better jets from those improvements.

FCR Tuning - Adjusting the Jets Slightly Leaner for Summer...

When discussing carburetor tuning, terms like "rich" and "lean" are often used. These terms can be a bit confusing for beginners.

FCR Tuning - Changing the Straight Diameter of the JN Jet Needle - 2023-05-09...

CBX1000 FCR Setting.Since last month, I have been gradually fine-tuning the settings. The idle and main jet are mostly decided. I’m focusing on the range affected by the straight diameter of the JN (Jet Needle), so this time I will change the straight diameter and take it for a test ride to see how it performs.

FCR Tuning - JN Jet Needle Straight Diameter and Clip Position - 2023-05-03...

Since changing the main jet, I’ve felt a power increase in my CBX1000. I’ve also been interested in trying changes to the slow jet and jet needle. I generally avoid adjusting the SJ (slow jet) when tuning the FCR, unless it’s beyond the adjustment range of the AS (air screw). For this reason, I decided to change the JN (jet needle).

FCR Tuning - 2023-04-12 - Considering the Jet Needle Strategy...

The other day, when I used the CBX1000 to go to a motorcycle event, I spent a long time on the highway. This is a story about checking the FCR's performance in terms of riding dynamics. Although I say I checked it, my overall impression was that the feeling I achieved seemed to be quite rich.

FCR Tuning - For street use, be sure to check the throttle response at the initial opening....

The FCR is a racing carburetor, but in reality, most users spend the majority of their time using it on the street. An important aspect in the street scene is starting. On the street, there are traffic lights, which means frequent stops and starts. On the track, once you start, there is rarely a complete stop.

FCR Tuning - Easily Adjusting for Each Season...

There are various owners when it comes to tuning FCR, ranging from those who want it to be perfect to those who are satisfied with around 80% accuracy. Among them, many owners prefer to adjust the FCR only within the range they can access.

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