FCR tuning – jet needle clip stage number change – 2022-10-16

FCR tuning – jet needle clip stage number change – 2022-10-16

This is about CBX1000 FCR tuning.
I am very satisfied with the current situation, even though I will do some tuning.
Changed for my knowledge.
The number of clip stages has been changed from [2] to [3].
Very good.
I was planning on putting it back together soon.
However, the number of clip stages will be set to [3] for the time being.
If you change the number of clip stages across seasons or after a while, you will often notice a big change in the ride quality and feel that it has gotten better.
It may not actually be getting better.
It's easy to feel the changes.
The range of throttle opening is around 1/4 to 1/2, so this is an area that is often used.
Changing the number of clip stages on the jet needle is an item that makes it easy to enjoy FCR tuning.
Finally, I changed the return of the air screw and finished today.
Other than that, I tried to advance the discharge timing of the accelerator pump by shortening the claw by 0.3mm, and I also tightened and loosened the pilot screw to see what happened.

CBX1000 FCR tuning

[Current tuning]
SJ-42
AS-2.00 minutes return
PS-3.00 minutes return
JN-90FXM#3
MJ-125
Acceleration pump diaphragm KLX250
Acceleration pump discharge large ring 1.6mm
AS Uotani SP2-Ignition [1]

Last time, the tuning was not very good.
After changing the number of clip stages of the jet needle from [2] to [3],
It feels like I touched the screw accordingly.
The feeling of acceleration, or rather the speed of the engine, changes depending on the timing of the accelerator pump.
My CBX1000 is equipped with an old model FCR.
There are two accelerator pumps.
The accelerator pump diaphragm has a lower total discharge volume.
When I looked at the air-fuel ratio meter and looked at the value indicating that the accelerator pump was working, it was in the 10.0 range. It only takes a little while.
This requires some consideration.
I will consider whether to change the MJ to around 130 for the winter the next time I drive at high speed.

working photos

I use roads in the back mountains with less traffic as my tuning courses. Although it is not possible to drive at full throttle,
At least this is an area where nearby residents have not been reported.
Also, I rarely meet other riders, so I enjoy tuning my FCR by myself.

For FCR beginners – Tuning is based on acceleration

I try to tune based on what happens when the throttle is suddenly opened from a stable air-fuel ratio.
Open the throttle an additional 1/4 way.
My CBX1000 is equipped with an air-fuel ratio meter, so I can see the partial air-fuel ratio in a stable state.
Don't get caught up in the air/fuel ratio.
However, I am concerned about numbers.
When I tune the engine, I think about whether the response is excellent when I open the throttle, which means that the engine accelerates smoothly and comfortably.
Even if you are able to maintain 12.5 in partial mode, if you open the throttle suddenly, the acceleration may feel unsatisfactory. If you turn on the quick throttle and open the throttle too quickly, the car will accelerate slowly or stall. The partial air-fuel ratio is generally around 11 to 12.0. If you do this, you will be able to ride the motorcycle comfortably. Try to see if it feels good when you open the throttle from the current throttle opening to a certain throttle opening.
For example, the engine speed increases when the throttle opening is suddenly increased from 1/4 to 1/2.
Please take a test run to check the correct gear tuning.
You can find the tuning that satisfies you. There are criteria to judge rich or lean, air-fuel ratio, burnt plugs, etc.
At the very least, it is a safe guideline to base your car on whether or not the feeling of acceleration is excellent.
If the tuning is so lean that it will break, it will not run properly.
Or being extremely lean only when the throttle is fully open is dangerous.
If it's a CBX1000, you can put 125-130 in the main jet and it won't be too lean and break.

FCR tuning – jet needle clip stage number change – 2022-10-16【summary】

To be honest, the previous clip stage number [2] didn't feel bad,
[3] felt better on the day I tuned it.
In any case, it is important to try it out if you are interested.
I consider FCR tuning to be an AB test. This means selecting the better one from the previous and current tunings. Actually, it is preferable to keep adjusting the number of clip stages until it gets worse.
We may make predictions based on past history, or we may decide to try it next time due to time constraints.
This time, I was thinking that changing the number of clip stages might improve the tuning. The current tuning is already in good condition.
I predict that if I set the number of clip stages to [4], it will be too heavy to run.
I try to consider whether to replace the jet by referring to past history and the values on the air-fuel ratio meter.
You really have to test it until it gets worse.
If you lower the number of clips any further, there will be no point in touching the top of the clip.

90FXM#3=90FTM#1
Comparison of FCR-jet needle cut-up. Let’s take a look at the thickness of the small standard 90FXM and 90FTM.

Changing the number of clip stages changes the driving feeling to the extent that it can be selected by feeling rather than by the air-fuel ratio. It is best to find the number of clip stages that you like before tuning.
I hope you all find the best number of clip stages.
See you again!