FCR Tuning-Test run and screw adjustment-22/10/25

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FCR Tuning-Test run and screw adjustment-22/10/25

I got a break from work.
It's around noon.
I did a test drive mainly to check the low throttle opening.
All you have to do is adjust the air screw and pilot screw and adjust the idling height.
My CBX has a two-pronged throttle wire.
There are two idling stop screws.
Changing the idling will cause a slight loss of synchronization.
It's only numbers 1 and 6, but I'm adjusting the idling stop screw while checking with the vacuum gauge.

Tuning with adjusted screws

[Current tuning]
AS-1.30 minutes
PS-2.00 minutes
Acceleration pump diaphragm KLX250
Acceleration pump discharge timing 1.6mm
AS Uotani SP2-Ignition [1]

It may be rich when idling.
Tighten the PS while adjusting the idling height and checking startability when cold.
Regarding the accelerator pump, I am currently planning on setting it to 1.6mm, but it starts discharging at around 1/4 of the throttle opening. It probably depends on how you open it quickly, but it doesn't feel like it's going to be fully opened, but it's only going to be 1/2. If you open it quickly and quickly, it will still be ejecting even when it is fully open.
It is better to visually check how you are blowing.
Driving feeling is also important when adjusting the accelerator pump.
Individual differences in throttle operation also have an effect.
The feeling of throttle operation will be consistent if the same person measures in the same way.

Impressions from the test run

The theme this time is to use low throttle opening and not use the accelerator pump.
Also, confirm that there is no problem even if you start with the shift position set to [2].
I did a test run of the motorcycle.
The above two themes have been cleared.
The acceleration feels good when the throttle is wide open.
During this tuning and test run, I didn't notice any bumps when the throttle was suddenly opened due to the accelerator pump. I will spend a little more time running it and fine tune the screw adjustments.
With the current tuning, the acceleration feeling is good.
During my next test run, I will be conscious of how to open the throttle and how effective the accelerator pump is.

For FCR beginners – What to look for when test driving – Partials and acceleration

Partial is a state where the throttle opening is fixed and the tachometer is stable.
If you are concerned about acceleration or partial performance, it is better to pay attention to the feeling of acceleration when tuning.
The great thing about a racing carburetor is that it accelerates comfortably when you twist the throttle.
In order to accelerate, you need to tune the accelerator pump well.
There are various ways of thinking, such as whether to make the partial rich in order to have a good air-fuel ratio during acceleration.
Opening the throttle increases the amount of air.
FCR is a racing carburetor.
I want to fully enjoy the feeling of acceleration.
My CBX has an air fuel ratio meter installed.
When I first started tuning FCR, I thought it would be good to have a partial air-fuel ratio of 12.5. Currently, I don't really care about the partial air/fuel ratio. I think 11.5th place is just right.
The reason for having trouble determining the air-fuel ratio when installing an air-fuel ratio meter is the air-fuel ratio during acceleration and the partial air-fuel ratio.

You won't be fooled if you tune only by feeling without looking at the air-fuel ratio meter.
However, if you have an air-fuel ratio meter, you should use it for tuning.
When you take a test run, be aware of how the acceleration will be.
Also be aware of how you open the throttle.
You should be able to find great tuning.

work photos

I have a vacuum gauge, but I use it to adjust the throttle stop screw.

FCR Tuning-Test run and screw adjustment-22/10/25【summary】

Lately, I've been trying not to complete test runs and settings in one day.
I try to split up the work.
There's also the fact that I'm used to the work.
If you write a little more specifically, you can now read the working time.
There is also a history of FCR settings.
It's now easier to make predictions and make settings, so I don't have to rush through the work.
A year ago, I was working while anticipating trouble.
I couldn't stop working in the middle.
I was working with plenty of time to spare.
It is very important to write down texts and leave notes.
Memos and history often improve the accuracy of work.

As a postscript, there are less than 100 days left this year.
The time to ride comfortably on the bike is running out.
Please spend this year without any accidents or violations.
Well then, see you again!
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