FCR Tuning – Adjust and synchronize air screw and pilot screw – 22/10/27

HONDA CBX-FCR Synchronization FCR
This article can be read in about 9 minutes.

FCR Tuning – Adjust and synchronize air screw and pilot screw – 22/10/27

I worked on the FCR synchronization and adjusted the engine startability.
Check startability when cold. The air fuel ratio is about 13.5.
Adjust by turning the pilot screw.
Once the engine has warmed up, check startability again.
Open and close the throttle at a slight angle.
This work also includes situations where the engine is cold.
I need to see how it goes over multiple days.
After a few days, if the starting performance is not bad and there is no problem with starting, the adjustment around the pilot screw is complete.
Once the engine has warmed up, synchronization work will begin.
We have confirmed that the CBX carburetor is synchronized to some extent.
Rather than synchronizing from the beginning, it is a matter of checking and fine-tuning.
I tried lowering the idle a little to get it in sync.
It is not a good idea to idle too low.
My personal experience is that it's a little lower than usual.
I adjusted the throttle stop screw to the extent that I could keep the engine idling when I started it when it was cold. The throttle should be slightly opened when it is cold.

FCR current tuning

[Current tuning]
AS-1.35 minutes
PS-1.15 minutes
Acceleration pump diaphragm KLX250
Acceleration pump discharge timing 1.6mm
AS Uotani SP2-Ignition [1]

I tightened the pilot screw from fully open.
I feel that there is no problem with rich when the throttle opening is slightly opened from fully closed.
Being too rich doesn't feel good either.
When the engine is warm, the air-fuel ratio should be below 13.0. When I didn't have a carburetor driver and couldn't adjust the pilot screw properly,
I repeated test runs while attaching and detaching the carburetor to determine the degree of throttle reduction.
The air/fuel ratio will be similar each time.
A good air-fuel ratio is around 13.0 when the engine is warmed up.
I made adjustments to keep it around 13.0.
Even if you tune multiple times, the air-fuel ratio will remain the same.
It can be said that the air-fuel ratio is appropriate.

Impressions from the test run

Currently, the accelerator pump becomes effective from about 3/8 of the throttle opening.
Therefore, the jet up to 1/4 is made richer.
I set the slow jet to 48.
In my opinion, it accelerates to the point where it's a little scary to open the throttle.
It feels like when you open the throttle, it accelerates as much as you open it.
Up until now, the accelerator pump was too effective.
My CBX is equipped with a quick throttle. The fuel that used to be discharged slowly
It is being ejected vigorously.
Lately, I have been consciously operating the throttle sloppily.
If you open the throttle roughly and accelerate with little stress, you'll get a nice boost.
The problem of the air-fuel ratio showing a rich value when opening the throttle suddenly and slowing down the engine's engine speed has been resolved.
Next time, I'll do a test drive with the intention of running at full throttle.

FCR – For Beginners – If you think something is wrong with the instruments, there is a problem.

My CBX is equipped with an air-fuel ratio meter. CBX is equipped with an analog voltmeter by default.
If I've ever encountered a problem where I thought something was wrong with the meters, it was likely that something was broken or something wasn't working properly. Here are three examples.

①The voltmeter drops strangely.
The generator was broken. I sent it in for a rebuild, so I don't know where or how it was broken.
②Air-fuel ratio meter shows abnormally rich when opening suddenly
The acceleration pump was too effective due to the quick throttle effect. It's not a tuning issue.
③ Even if you synchronize with the vacuum gauge, it is strange
The vacuum gauge was not calibrated for each cylinder.

It may not be directly related to FCR tuning.
However, the gauges give a hint that something is wrong.
If you are concerned about the meters, there is a high possibility that something is wrong.
Even if it's not a big deal, you may find out the cause later.
If you feel that the meter movement is strange, remember it and you will be happy.

works photos

Once you get used to it, it won't take long to synchronize.

FCR Tuning – Adjust and synchronize air screw and pilot screw – 22/10/27【summary】

We have the rare opportunity to hear stories and opinions from professionals.
There are some professionals who say that you should synchronize, but you don't need to synchronize frequently.
I also feel like I don't have to worry about it that much.
The master who repaired my CBX engine said that synchronization is important.
I try to ensure synchronization whenever possible.
As you work, you will make various small discoveries.
I hope everyone has a fun FCR life!
Then see you again!
Copied title and URL