Test run with FCR-MJ throttle fully open2020/06/04

HONDA CBX-FCR float chamber FCR
This article can be read in about 10 minutes.

Test run with FCR-MJ throttle fully open2020/06/04

This is my impression when I drove FCR's main jet MJ at full throttle.
The other day, I went on a slow-paced tour with a senior who rides a KAWASAKI Z1000J.

Old folk house cafe Matsubaya in Masuda City, Shimane Prefecture
This is a story about going on a tour. Please use this as a reference when planning your course. Suitable for people living in Hiroshima or Yamaguchi prefectures. It starts from the Hiroshima Kita Interchange in Asakita Ward, Hiroshima City, Hiroshima Prefecture. The course is to visit three locations and then return home.
I didn't run it especially for the tuning, but for touring I took the expressway alone on the way home, so I was able to test MJ at full throttle. I will write as much as I can remember as a history, including reviews at that time.。

FCR current tunings

AS-1.40 minute
PS-1.15 minute
This is the tuning.

My impression is that it seems to be able to reach the maximum speed, and although it takes a little time to reach 200km/h, there are no problems.
spin. Should we make MJ bigger? I felt that if I made it smaller, I would be able to feel a little more acceleration and be able to easily reach 200km/h, but with my current sense, it was impossible to get a feel for it in a test drive.
As I wrote in the article about touring at the beginning, there is a relationship between the rotation speed limit and the rev limit, so I can't make a general statement, but the rev limit should either be set without a limit or set at a slightly higher rotation speed. I understand that there is.

Also, if you return the throttle halfway when the throttle opening is around 1/2 to 3/4,
For a moment, I felt like I was being hit. By the time I got back up to twist the throttle to full throttle,
Is the throttle operation incorrect? Is the accelerator pump too effective? Check it consciously.
I have to keep it in moderation so I don't die, so I don't know if I have the guts to try it again. I'll probably try it though...
HONDA CBX-FCR float chamber
HONDA CBX-FCR float chamber

FCR’s next tuning changes

You need to immediately set the AS Uotani rev limit dial to either [9] 11000 or [A] 11200.
You need to compare the accelerator pump's diaphragm to larger or smaller.
Generally, check the throttle opening from 1/2 to 3/4 to full throttle.
Let's compare rough throttle work and careful throttle work.
Sloppy throttle work involves retuning it halfway and then suddenly opening it fully.
Careful throttle work can be done by stopping the throttle until it is fully open, but try not to let it go back up as much as possible.
The accelerator pump will eject once more when you release the throttle.

FCR-for Beginners

It is better to buy MJ as a set than to buy one by one. I feel that the price is quite low.
The accuracy is not low even with products other than KEIHIN products.
Sold as a set, you get 1.5 jets instead of one jet, which is a good deal, and it also comes with a case.
Also, I have posted the manufacturer's URL link below.
If you buy from Amazon or a shopping mall, the price will be a little lower.
If you buy them individually, MJ and SJ have 4 numbers in the 1's digits: 0, 2, 5, and 8, but it may not be a problem to have them with only 0 and 5. The number simply represents the size of the hole.
For MJ-125, it is 0.125mm. You need to compare the before and after tunings.
With MJ, when the number changes by 10, it feels like the air-fuel ratio changes by about 1, and the range of influence varies by about 1/4 depending on the throttle.
For SJ, we believe that the appropriate range of AS changes by about 10 minutes on the clock every time you change the number.
Even if you change the number 10, the return number will not change by 1 rotation, and the air-fuel ratio will not change dramatically.
The appropriate number of AS returns is getting more and more deviated.

About set sales
For MJ (main jet), there is no problem if you purchase a 6-stage set of 100-112 and a 6-stage set of 115-128. You need to buy 6 pieces in a 6 piece set.


I purchased and am using a set of 6 POSH.
I bought 6 pieces of SJ each time from 35 to 55 and tried them out. At first, I thought it would be okay to touch on it a little.
In the end, there were 54 pieces in 9 stages, 6 pieces each, from 35 to 55. I don't know the price right away, but even if it costs 300 yen each, it's 16,200 yen.

SJ can be adjusted with screws as long as it's not too far off, so any size is fine.
If it is about 40-55, AS will fall between 0.5 and 2.5 rotations.
They are sold in sets of 3, so if you purchase them so that 42 or 45 will fit in them, you will generally have no problems.
I need to buy 6 sets of 3 sizes.


If SJ's 35 is a CBX, the AS will be around 0.25 rotations, so I cannot recommend it.
However, I will run. There is no problem with starting the engine.
Also, with a low throttle, the throttle opening is very severe from idling and clutch engagement to about 1/8, but with a high throttle, it can be run even with slightly rough tunings such as starting with a wide throttle opening. There may be no problem. The more you turn the AS back when idling, the lower the engine will be and the less power it will feel. The larger SJ is, the larger the appropriate number of AS returns will be.

Test run with FCR-MJ throttle fully open2020/06/04【summary】

In the end, I ended up posting something that didn't have any photos to post.
I write it every time, but I do so because I think it would be good to deepen my knowledge by putting it into words. I hope this will be helpful to someone who reads this, not just for myself.
Regarding the carburetor, I will continue to touch it until the CBX breaks.
If I were to write about FCR next, I would probably write about the results of replacing the accelerator pump's diaphragm.
If you are interested, please check back regularly.
Please enjoy a wonderful FCR life.
See you again!
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