FCR Tuning – Cold Startability – Air Screw and Pilot Screw Adjustment – 22/11/01

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FCR Tuning – Cold Startability – Air Screw and Pilot Screw Adjustment – 22/11/01

The other day, I adjusted the air screw while watching the idling with a digital tachometer.
I tightened the pilot screw to the lean side.
I'm also checking the air screw without returning it for 15 minutes after setting it back to maximum rotation during idling.
The reason is that I have an air-fuel ratio meter attached, so I wanted to see the situation based on when the oil temperature was high.
So today, I checked the startability when cold.

This is the result.
It's only slightly good. I know that I can start the engine a little more easily.
I adjusted the air screw and pilot screw slightly to make it richer before the engine warmed up.
① First, tighten the air screw in the rich direction for 10 minutes.
② Adjust the pilot screw in the rich direction so that the air-fuel ratio is approximately 12.5 to 12.9.
It takes about 5 minutes because I do it while watching the air-fuel ratio meter.

So the idling is low, but it idles tenaciously.
Recently, the pilot screw has become a little rich, but I don't think there is any problem with it.
I don't know what the disadvantages are, but fuel efficiency gets worse, gasoline smells worse,
It becomes difficult to start and maintain idling.
On the other hand, lean will result in a lean state with no sense of power when starting.

CBX current FCR tuning

[Current tuning]
SJ-48
AS-1.20 minutes
PS-1.05 minutes
JN-90FXM#3
MJ-130
Acceleration pump diaphragm KLX250
Acceleration pump discharge timing 1.6mm
AS Uotani SP2-Ignition [1]

Compared to when I changed the slow jet from 42 to 48 a while ago, I tightened the screw considerably. It is different if the pilot screw is abnormally rich, but if it is within the normal rich range, there is no problem. It's gotten much colder over the past week.
Changes in screw adjustment are also affected by the cold.
Winter in Japan affects tuning.
There is no problem with just looking at past history and making predictions that may be slightly better. If you adjust it to lean, I would like to see the start and acceleration feeling.
I keep repeating these steps to check the startability of the engine when it's cold.
If you replace the jet, you'll have to start over from the beginning, so it doesn't make much sense...
And it feels good when the engine starts well.
If the engine starts poorly or the battery is weak, the plug may become fogged up in the winter and nothing can be done about it.

For FCR beginners – rich or lean cannot be seen in the plug

I've heard that the color of the plug is black and white.
When tuning, it is nonsense to tune by looking at the color of the plug.
Where and how much of the plug changes color? How far should I drive?
It's not clear.
Plug rich or lean is average rich or lean.
To be honest, I don't know in what area and how much the color of the plug changed.
You should judge by actually driving rather than by the color of the plug.
If there is no comparison target, the only option is to compare with the previous history.
Increase the accuracy of the current tuning by comparing whether it has improved or worsened.
The shortest way to tune your car is to equip it with an air-fuel ratio meter.
That way you can easily tell if it's rich or lean.
If you are interested, please consult your local custom shop.

FCR Tuning – Cold Startability – Air Screw and Pilot Screw Adjustment – 22/11/01【summary】

I have touched the idling stop screw a lot, so I would like to check the synchronization.
At that time, use the digital tachometer to adjust the screws for each cylinder in either 5 or 10 minute increments. It is also important to repeat the work.
By writing a blog, I have acquired the habit of thinking and working.
I can do more things now than I did a year ago.
I will continue to tune FCR until I hate the work.
I hope you all have a fun FCR life.
See you again!

*Today's CBX is listed at the bottom.

Today’s CBX gallery

The air fuel ratio meter has just woken up.
It's around 5pm in the evening, so the contrast of the colors is a little off.
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