FCR tuning – Acceleration pump adjustment – If it is too fast, it will hit the throttle valve.

HONDA CBX-FCR-Idling Biker&Others
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FCR tuning – Acceleration pump adjustment – If it is too fast, it will hit the throttle valve.

This is an example I found the other day.
The fuel injection from the FCR's accelerator pump hits the throttle valve.
The fuel is not being sucked into the engine, but is instead hitting a door called the throttle valve.
There may be conditions such as opening the throttle and quickly retuning it while the engine is running.
I don't want my behavior to change due to unexpected conditions.
Currently, the discharge timing of my CBX acceleration pump is 1mm.
I noticed the change when I tried speeding it up a little.
I don't want the fuel to hit the throttle valve, so I'm currently changing the discharge timing to 2.3.

It's not a good thing when you're doing tuning to have different operations occur, such as hitting the throttle valve or being sucked in without hitting the throttle valve.
Things that are not intended cannot be said to be under control because they are out of control.
There is a possibility that it is the same whether it hits the throttle valve or the fuel is directly sucked into the engine.
In my current thinking, I cannot think of them as being the same.
Perhaps the design philosophy is that it doesn't matter because it's a rough idea to begin with.
In my case, it's street use. I often use up to 1/2 throttle opening,
Throttle operation is rough.
The discharge port of the accelerator pump hits the discharge at around idling. It's about the extent that it hits even when the throttle opening is 1/8.
It will hit if you close the throttle suddenly while discharging.
Accelerator pumps are not quick, so they may continue to be discharged for a short time even after the throttle is released.
If the discharge timing is too early, the discharged fuel will directly hit the throttle valve.
The FCR throttle opening and throttle valve opening are not directly proportional.
When the throttle opening is about 1/2, the throttle valve will open about 1/4 by visual inspection.
Visually, when the throttle opening is about 3/4, the throttle valve will be about 1/2 open.

Appropriate value for accelerator pump (appropriate range)

This is based on this post.
There is nothing in the setting manual that says that fuel hitting the throttle valve is a problem.
My subjective opinion is that if fuel hits the throttle valve, it will be bad.
0.6mm or more and less than 3.0mm.
0.6mm is the default condition when shipped from FCR.
Based on the story in this post, 1.2mm or more might be better.
By the way, even with 5.0mm, it was being discharged at about 3/4 throttle opening.
If the timing is set too early and the discharge time is too long, fuel may hit the throttle valve directly when the throttle is released.
In this respect, I think that a discharge timing of 1.2 mm or more and less than 3.0 is appropriate for FCR.
Of course, it depends on things like how quickly you open the throttle, so it's hard to say for certain.
At least I wrote this with the point in mind that it should be at a height where the fuel does not hit the throttle valve.
The tuning manual states that if you tune to discharge from the idle opening, please be careful as the idle rotation may become unstable.

FCR throttle operation

I don't want to worry about throttle operation, but I think that continuous operation of suddenly opening and closing the throttle should be avoided.
When I test drive, I intentionally operate the throttle sloppily.
What I have learned is that when you open and close the throttle suddenly, the fuel hits the throttle valve directly. In the first place, if the discharge timing is too fast, it will hit the throttle valve directly from the beginning of opening.

For beginners to FCR – Try adjusting the amount of acceleration pump.

The total amount of discharge can be adjusted by changing the diaphragm of the accelerator pump.
This is probably a part that was officially released after the FCR tuning manual was written.
You can order the diaphragm as a genuine Yamaha or Kawasaki part.
I won't go into detail here, but please keep in mind that there are such parts.
↓Past articles will open↓
FCR tuning-Acceleration pump adjustment-22/07/06

I haven't felt much improvement or deterioration since using the accelerator pump.
The feeling of acceleration is different when you switch between on and off.
When changing the discharge amount by changing the diaphragm,
I feel like things have changed and gotten better.
On the other hand, even if you reduce the discharge amount and take a test run, you may feel that the engine revs up better.
When there is a change, the placebo effect also comes into play.
I consider touching the accelerator pump to be the last stage of tuning.
If you tune with the accelerator pump, it will be difficult to judge.
During tuning, it is better to reduce the effectiveness of the acceleration pump or turn it off and not make any adjustments until the final stage.

*Precautions when replacing the accelerator pump
When changing the accelerator pump diaphragm, there are two O-rings.
The diaphragm of the accelerator pump has a direction.

FCR tuning – Acceleration pump adjustment – If it is too fast, it will hit the throttle valve.【summary】

It was a great day as I discovered something new about FCR.
I didn't notice any problems until I noticed it.
It may not be a big problem for FCR settings.
In my opinion, I don't like it when fuel hits the throttle valve.
For the time being, the discharge timing of the FCR acceleration pump will be 1.2 mm or more.
Thank you everyone for taking time out of your busy schedules to read to the end.
I hope you have a wonderful FCR life.
Well then! See you again!
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