FCR-SJ slow jet-FCR carburetor installation

FCR-SJ slow jet-FCR carburetor installation

I set it up after removing the FCR.
I will post a photo of the FCR installed.
I write the tuning.

[tuning]
SJ
48→40→Test run→48

jet needle
90FTR#2
MJ
118

I changed the slow jet from rich to lean.
I changed the count from 48 to 40.
What I simply wanted to do was
Does opening and closing the PS of only one cylinder increase or decrease the rotation speed?
I wanted to try it.
By making the SJ lighter, the PS will only move in the direction of richer fuel.

As a result, there were no obvious changes.
The verification method is to set the PS to PS1.0 on all cylinders and turn it from fully closed to 3.0.
The increments are about 15 minutes.
I verified SJ with 40 and 48.

When I adjust AS, I refer to the [air-fuel ratio meter] and [a/f meter].
Generally speaking, we prioritize and adjust the following three points.

The first priority is to be able to start when the clutch engages.
The second priority is to be in good condition when starting. There is a high possibility of starting, and to some extent even when it is cold,
I set it back to a level that maintains idling.
The third priority is to ensure that the air-fuel ratio is as expected up to 1/8 throttle opening.
With my current tuning technology, changing the return number for each cylinder means:
It doesn't seem possible.
Although the verification was performed with only one cylinder, by shifting all three cylinders at once,
If I tested it, I might have gotten a different result.
As a result of verification, even if you touch the PS on only one cylinder, it is difficult to notice the change only when idling.

FCR installation-preparation

Adjust the throttle wire, idle stop screw, acceleration pump, etc. as much as possible.
After touching the throttle wire and idling stop screw, be sure to synchronize the carburetor.

The FCR's accelerator pump is adjusted according to the width of the notch.
There are also instructions in the manual.
However, since the shape is difficult to measure, it is difficult to match in 0.1 mm increments.
I don't really understand how to adjust the float oil level and the accelerator pump with high accuracy.
There is a question as to whether a carburetor can be called a precision device.

Even if the vacuum gauge is new, the needle is out of order.
I always calibrate the needle before using it.
Secure the rubber hose attachment port with an insulation lock.
Make sure that the vacuum gauge needle does not move easily before starting the engine.
The vacuum gauge may be damaged.

When using a two-pronged throttle wire, confirm full closure with the top screw. The aim is to start opening at the same time. For full opening, I adjust it with a throttle wire so that it opens fully at the same time. I adjust the play on the throttle side. After placing the tank on top, turn the handle to the left and right to see if it gets caught. When it comes to opening and closing the throttle valve, a carburetor with a two-pronged throttle wire has a huge disadvantage. You can hardly feel the benefit of having two legs. The disadvantage is that the strength of the throttle wires must be the same.
Being able to divide it may improve work efficiency, but there is also a problem with work efficiency due to division. I have never touched an FCR that can be drawn with one stick. However, I think it is better not to use a two-pronged throttle wire.

Impressions from the test run

I felt that SJ48 was better. I don't drive that fast.
My purpose was to verify.
But I added the work of changing SJ.
I keep a history of tunings so I can restore them.
If the throttle opening is low or the speed is low, you can use a screw such as AS.
Even if the tuning becomes impossible to drive, it will be returned to the original tuning immediately.
SJ has a lot to do with screws.
The SJ's role is to determine the range of the screw.
Replace SJ if it is outside the range of the screw.
This is my impression after a test run. I wanted to output power air fuel ratio during acceleration.
I wanted to respond when the throttle was suddenly opened.
I have a large SJ.
But it wasn't my current taste. I changed it back.
A richer air-fuel ratio does not necessarily mean worse fuel efficiency.

FCR-SJ slow jet-FCR carburetor installation【summary】

[FCR] is a highly versatile retrofitted carburetor, so it can be used from other car models.
There are some things that would be better if they were added somehow, so I think there are also aspects where maintainability would be worse.
I wonder if V-type engines have similar problems. I think one of the basic concepts of racing carburetors, including FCR, is that they can be easily set up.
I think the reason I enjoy tuning up the FCR is because of the [air/fuel ratio meter] [a/f meter]. I think that when professionals make adjustments without an air-fuel ratio meter, they prioritize the feeling when tuning, so they prioritize the feeling of driving. However, non-professionals only touch their own vehicles, so I wondered if it was too thin and would damage the engine. I think there is some anxiety, such as not knowing whether things are going well or not. Air-fuel ratio meters can be installed at low cost. I think it would be a shame if you don't touch any racing carburetor, including FCR, yourself.
The reason is that even if you ask a shop to do it for you, you won't know if the tunings are good or bad.
Some people install it as a dress-up.
I feel like it would be a waste not to enjoy the tuning.
At least, I think we are now in a world where even beginners can do something by searching the internet, carefully reading the FCR tuning manual, and looking it up on YouTube.
In the days when the internet was not widespread, there was so little information that I felt I had to consult shops and people in the know.
I am also starting as an amateur who has never done it before.
I think it might be helpful if I explain it from the perspective of an amateur who is stepping up.
Well then! See you again!