FCR Tuning – Easy way to turn off the acceleration pump

FCR accelerator pump locking clip FCR
This article can be read in about 8 minutes.

FCR Tuning – Easy way to turn off the acceleration pump

All you have to do is clip the push rod of the accelerator pump to prevent it from moving.
that's all. I will also add a photo, so please check the size and position of the clip.
If you are using an older model of CBX FCR, there are two standard carburetors.
You can't reach it unless you remove the carburetor.
I will also write notes and column-like sentences after explaining the photos.

Photo of tuning off the accelerator pump with a clip

The size of the clip is approximately 19mm x 9.5mm.
Lift the accelerator pump rod and secure the accelerator pump with a clip to prevent it from moving.
Try tuning the throttle and see if it falls off.
Although it is not possible to control the total discharge amount or discharge timing of the accelerator pump,
It turns off completely.
Even if it's not a clip, it's OK as long as the push rod doesn't move.
The size of the clip is just an example, so there is no problem with any size, whether it's a little bigger or smaller as long as it meets the requirements of not moving the push rod.

Is an accelerator pump necessary for FCR?

The conclusion tends to be controversial.
But there is no answer.
Logically speaking, it is necessary.
The FCR's acceleration pump feels sloppy to control.
I would like to use an accelerator pump.
The effect that the accelerator pump is aiming for is that the engine sucks in a large amount of air when the throttle is opened.
At that time, there is more air and the FCR shows symptoms of being thin.
The idea behind FCR's accelerator pump is to directly supply fuel to compensate for the increase in air.
The carburetor operates using the suction power of the engine.
It will definitely get thinner depending on how you open the throttle.
The accelerator pump compensates for this.
It's a great feature, but it's a sloppy mechanism.
We have no choice but to live with it as a function of a crude mechanism.
The problem is that YMAHA SR and he use the same accelerator pump on HONDA CBX.
There is no problem with driving even if the accelerator pump is off.
It's a great feature, so I want to make good use of it.

For FCR beginners – I don’t understand the effectiveness of the accelerator pump

Since the accelerator pump gets in the way during tuning, I reduce the total amount of discharge.
It's also a good idea to turn it off and turn on the accelerator pump when you're done tuning.
However, since the tuning is based on the assumption that there is an accelerator pump, the total discharge volume should be reduced,
I'm tuning. I generally don't touch it much.
If the discharge timing is too fast, the discharged fuel will directly hit the throttle valve.
In the case of my CBX, it sometimes hits even with 1.6mm timing.
I'm currently using 2.3mm.
This is an easily adjustable part.
If you feel like it, try touching it or tuning it on and off and enjoy the difference.
This also leads to the idea of acceleration and partial.
It's better to try different things.
This function is necessary from 1/2 to full throttle rather than low throttle opening.
FCR is a racing carburetor.
This is not a repair carburetor.
If you want ease of riding at low throttle openings, tune the car to be a little richer in fuel.
Alternatively, you can counter this by tightening the air screw significantly.
Strict control of low throttle opening is for daytime use.
Relying on trivial functions like accelerator pumps is not compatible.

FCR Tuning – Easy way to turn off the acceleration pump【summary】

You can find out whether your motorcycle needs an accelerator pump by tuning it on and off.
Please check the difference between on and off for each throttle opening, such as the acceleration feeling when suddenly opening from 1/8 to 1/2. I feel like it doesn't need to be about 1/4 throttle opening. Also, I would like to know someday if there is a problem with the fuel being discharged into the throttle valve directly hitting it. Currently, on the premise that there may be a problem, I try to discharge fuel at a time when the fuel does not directly hit the throttle bubble. I've been trying various things to determine the total amount by replacing the accelerator pump diaphragm, but they all make a difference, and it's hard to decide which one is better.
FCR's accelerator pump seems to be incomplete compared to TMR. However, this function was added as an evolution from the CRS carburetor. I will make good use of it and enjoy motorcycling.
I hope you all have a wonderful FCR life.
Well then! See you again!
Copied title and URL