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CBX FCR tunings. I mainly tried the MJ main jet.
It's not in bad condition now, and when I drove on the expressway, the air-fuel ratio was 12.5 at full throttle and partial.
It is unclear whether it is accurate at full throttle because it is difficult to measure the air-fuel ratio during partial and acceleration, and it is difficult to maintain the throttle opening for a long time.
This time, I assumed that I would change the MJ in the direction of making it richer, and I wanted to see the change in the hit between 1/2 and 3/4 of the throttle opening.
There seems to be no problem even if MJ is still on the richer side.
You should be able to adjust the acceleration feeling a little more at the throttle opening of 1/2 to 3/4.
The current tunings are fine, but I'm looking for a way to create a better sense of acceleration.
It feels a little strange when the throttle work is sloppy, so I would like to improve that as well.
I think the expected result will be a rich tuning.
If time allows, it would be a good idea to set it up including the number of JN clip stages.

work photos

I haven't taken the tank down, but after removing the FCR, I removed the drain bolt at the bottom and replaced the MJ main jet. Please note that the photo of the main jet is only out of focus.

FCR-MJ exchange

Current tunings
AS-1.30 minutes
PS-1.15 minutes

AS-1.30 minutes
PS-1.15 minutes
@I only rode it a little, but the feeling is better with a larger MJ

AS-1.35 minutes
PS-1.15 minutes
@I get the impression that it has become richer overall,
I feel like the discomfort I had when opening the throttle suddenly has been alleviated, but around 1/4 of the throttle.
It feels heavy, so it may be necessary to consider lowering SJ or changing the straight diameter of JN.
I might be able to finish it by just adjusting AS, but I would like to try adding a little more information about MJ. Around 138 would be appropriate, or the current 132 would be appropriate. The feel itself is also good.

FCR-For Beginners-MJ Exchange

This is a story for beginners, so there are professionals who can set up using Dynojet,
Analog tuning professionals who have their own theories are not eligible.
When replacing MJ, it is better to replace it with a value of 10, 7, or 8 and see how it goes.
Also, you may choose by looking at the effect at around 1/2 to 3/4 throttle opening.
In the end, there are very few opportunities to try the full range. If the throttle opening is set properly around 1/2 to 3/4, the MJ's full opening range will not be that far off.

The piston did not melt even if I drove at full throttle for about 1 second with MJ102.
This is a story about tuning a limit at 9200RPM with CBX.
I currently have the limit set at 10200RPM and have not tried anything below 115.
Once you have found a good tuning, you may want to set the MJ at full throttle again. tuning at full throttle is difficult for less experienced riders without an air-fuel ratio meter or dyno jet.
If you don't have an air-fuel ratio meter, you won't be able to get a numerical answer. Amateurs like me have no experience on circuits or other machines. Since I don't have a feeling to guide me, I set the tunings that can be called the correct answer.
Even if you arrive at it, it will take a long time to realize that it is the correct answer.
You need to set the richer side to a tuning that is intentionally removed, and the leaner side to a tuning that is intentionally removed. It's the same even if you have an air-fuel ratio meter, but the level of difficulty in doing the same thing is completely different.
Equipping yourself with an air-fuel ratio meter is the first step to becoming a beginner.
We recommend that beginners consider installing the product.


There is one thing I should reflect on this time.
Regarding MJ exchange, I regret that I should have tried 138 or 142 before heading home.
Obviously MJ132 was good, but there was room for it to be better.
I didn't pass the exam because I went home without trying it.
The next thing I did was replace MJ, so I felt like I was just taking a break along a straight road with no forks. I thought the correct answer when to stop today's work would be to change the jet to the point where it seems no good, or to take time to consider the next change.
Maybe he was unconscious because of the heat. I would like to utilize this experience in ways other than tuning.
I hope you have a good FCR life.
See you again!
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