FCR – Adjust the diaphragm of the accelerator pump

HONDA CBX-FCR acceleration pump FCR
This article can be read in about 21 minutes.

FCR – Adjust the diaphragm of the accelerator pump

My CBX is FCR specification. There are two accelerator pumps and two throttle wires. This time, we replaced the standard diaphragm of the accelerator pump with a diaphragm for KX250.
By replacing the diaphragm, the overall discharge volume of the accelerator pump will change.
There are many ways to adjust the accelerator pump. There is also a way to turn off the accelerator pump.
The adjustment method written in the manual only controls the timing at which the accelerator pump starts working, but does not seem to include detailed adjustment methods or specific measurement methods.
When adjusting or tuning multiple items, touch only one item as much as possible.
It is safer to compare before and after.
In other words, there are many parts of FCR that are invisible to the naked eye, so this is the basic adjustment method. Until the other day, we had an accelerator pump as standard, but this time we decided to use an accelerator pump with a smaller discharge volume than the standard one.
Utilizes the diaphragm of the acceleration pump for Kawasaki's KX250.
Currently, the only two types of diaphragms I have on hand are the FCR standard and the Kawasaki KX250.
Recently, I've been enjoying the feeling of acceleration by adjusting the tunings.
It felt bumpy when I did rough throttle work.
This time I will try changing the accelerator pump.
Sloppy accelerator work is like suddenly closing the throttle halfway and then opening it again when driving at high speed. Is it because of the throttle work that you don't like it? Is it a seasonal issue and the discharge amount of the accelerator pump does not match? I just wanted to try it for the sake of knowledge.
Currently, it doesn't bother me at all unless I do some rough throttle work.
There may or may not be a change in terms of ease of riding.
You may be able to ride the motorcycle more comfortably by changing the size of the accelerator pump between summer and winter.
It may depend on the throttle opening, but the engine runs well in the summer,
Is it better to make the accelerator pump smaller than the standard size? That's what I think.

How to adjust the accelerator pump

@Diaphragm replacement
・FCR standard (large) 1201-055-2102
・For KX250 (medium) 43028-0001
・For KX400 (small) 43028-0006
It looks like you can control it by rearranging it in these three ways.

@Use a washer
You can understand this by looking at the photo of the accelerator pump diaphragm.
There is also a way to control it using a washer etc.
I don't know if it works properly as I have never tried it.

@Fix the push rod
There is a push rod that pushes the diaphragm.
If you control or lock its movement,
It is possible to limit the movement of the accelerator pump or turn it off, but since the CBX has accelerator pumps attached to the 3rd and 6th carburetors of the 6 cylinders, it seems difficult to control, so I decided to do this. I have not. There seems to be a way to fix it with a clip or by covering the push rod with an aluminum pipe.

@Use exclusive products
The best method may be to use a special product, but even in uncertain areas that cannot be measured,
Please consider whether the cost performance is right for you before purchasing.
Currently, I am trying to control the timing of discharge start by using different diaphragms, large, medium and small.

FCR-diaphragm replacement work

[Note] Please be sure to refer to the photo.  
Even though it is called a replacement work, the work is just replacing it, but there are a few things you need to know about gasoline leaks and other problems.
There are some good points to keep in mind. The replacement process is just to remove 3 screws and replace, so I will mainly write down the precautions.
・O-ring and U-ring are available. They are facing the same way and are easy to lose.
Rather than having two O-rings of different sizes, the larger one is the O-ring and does not have a front or back side.
The smaller one is a U-ring and has a front and back side. The one that is flat is the one that is curved on the cover side.
It's on the body side. If you think about it calmly, you'll understand that the shape is to press the seam between the body and cover, so the side that will be crushed should be in contact with the seam between the body and cover.
Also, it is a part that is easy to lose, so be sure to check where it is from the beginning.

・The diaphragm has a direction.
According to FCR standard, the side with the stamp faces the seam of the body and cover.
The engraving is on the bottom, facing the ground.
The diaphragm for KX250 has a protrusion in the center, which faces the joint between the body and cover.
It's hard to see the stamp, but it's there. Point the engraved side toward the seam between the body and cover.

・Diaphragm lifespan
There are various judgment methods. The discharge of the accelerator pump was working well,
If it doesn't work, it's the end of its lifespan.
The diaphragm is shaped so that it sticks to the body and is sealed.
Even if it can no longer be sealed, it has a service life.
You can visually check whether the accelerator pump is working properly.
If you feel that it is not working properly, please replace it immediately.

・How to tighten the cover
There are three bolts, but make sure to remove any dirt from the mating surfaces of the body and cover.
After temporarily tightening the three, tighten them evenly. There may be variations in the amount of force applied,
If you tighten only one part first, it may lead to gasoline leakage.
Please note that the same can be said about float chambers.

・Check push rod
When the float chamber is removed, the push rod of the accelerator pump is inserted into the specified hole.
Please check if it is included. This is an item that rarely occurs when you notice it midway through and have to disassemble it again.

・Check the operation of the accelerator pump
Please check operation before installation. It is definitely a good idea to get into the habit of checking the operation of the accelerator pump before installing it. If there is a problem, it is almost always due to improper installation or a misaligned diaphragm. If you install it without checking and notice a defect while driving, the only place to check will be the accelerator pump. This will cause you to waste unnecessary time.

FCR-For Beginners①-Is an accelerator pump necessary? Unnecessary?

This is about CBX.
Is it better or worse to have an accelerator pump? That being said, it's definitely better to have one.
It's included because it's better to have. It is not necessary for SR etc. as the discharge volume of the accelerator pump is too large.
Rather than saying anything like that, you just need to make adjustments so that you can supply the necessary amount when you need it.
This is where the story becomes vague, or rather, where differences in thinking begin to emerge.
It's really fun to think about things like this.

There is also the idea that it is better not to have an accelerator pump during tuning.
It seems like it takes a long time for the air-fuel ratio meter to show partial when the accelerator pump is working.
I think FCR should have an accelerator pump, but at full throttle or in a high speed range,
It can be a little difficult when looking at numbers.
It depends on how you set it up, but you can compensate for the missing parts with an accelerator pump. Opinions vary depending on the individual, such as tuning it up assuming that there is an accelerator pump.

Another reason why it is unnecessary is how to use FCR.
I believe that motorcycles should be fast.
The reason why other people use FCR is that the normal carburetor cannot be used for some reason.
There are some riders who use FCR and don't chase performance, so they just need to keep moving even if things aren't going well.
At least in my current way of thinking, it's not something you'd be bothered to have, and it's something you might be in trouble if you didn't have.
That's how I think about it.

FCR – For Beginners ② – Is FCR for CBX? Is it CRS?

If you want to touch it yourself, it's definitely FCR. It is easy to set up.
And there is a lot of information out there.
I will write about the looks of the carburetor.
CBX has a matching tail cowl and is old, but it's not an extremely old design, so
FCR doesn't have any damage to its image. If the old one looks better, use a normal carburetor.
I feel like it would be cooler to wear it. CBX has extremely poor maintainability, so if you use an air cleaner box, you have to tilt the engine forward every time. For this reason, a power filter may be installed. Since it is not a normal look at this point, is it classic to wear CRS? Is it closer to normal? In that sense, it is difficult to understand the meaning.
Regarding the price, it seems that CRS can be purchased at a lower price, so it seems that there are people who purchase it for that reason. Considering the price, if you don't handle it yourself, you will have to pay for the labor, so you will need to consult with your motorcycle shop about what will happen in that regard.
As for the difficulty of tuning, I have never touched CRS, so I am not sure.
FCR wins because it is easy to set up and has a wide variety of tuning parts.
For those who request a custom shop to install and set the carburetor and then ride the car as is.
It doesn't really matter if it's easy to set up or not.
The easier it is to set up, the lower the labor cost.
It appears that CRS may be used when FCR cannot be used due to race regulations.
I heard this from someone else, but it makes sense.

Considering performance and ease of tuning, FCR should be used.
Regarding looks, I like the design of CRS rather than FCR destroying the image of CBX.
I feel that choosing CRS is the correct choice.
FCR was the first in the lineup that was usually easy to obtain in Japan, and I feel like I've started to see CRS installation kits recently.
If it's your first purchase, it's unlikely that you'll feel like you made a mistake by buying FCR.
You may regret that you should have bought CRS and changed to FCR.
Also, if you can choose one considering your budget, but if you have TMR in your tunings, TMR is a later carburetor, so its performance is definitely better.
Another possible reason to choose CRS is if you own CRS tuning parts for other motorcycles and have high asset quality and knowledge.
Choosing a CRS without a clear purpose is likely to lead to a sad outcome.
I don't want to worry about other people's views or opinions, but I still don't want to worry about people's opinions or opinions.
I feel sad when people say that it's uncool.
Uncool is something that is unnecessary for running or maintaining beauty.
When choosing CRS, it is important to have a clear sense of purpose.

FCR – Adjust the diaphragm of the accelerator pump【summary】

I intended to write about accelerator pumps, but the comparison between FCR and CRS turned out to be too long.
There is a big difference in whether or not there is an accelerator pump, and the FCR is the successor to the CRS.
I have never seen a CBX equipped with [CRS].
I hope for the day when I can actually see it.
I always worry about the orientation of the accelerator pump's diaphragm.
There are many people who have come before me who have provided explanations in places other than my blog.
It only takes a little time before starting work, so it is very efficient if you do some preparation before starting the work.
For those who just want to try out FCR for themselves, it will make you feel like you've touched it,
It's not a bad item. Since it is an item that cannot be clearly visualized, the person riding the vehicle
If you like it, it's perfect.
Then I'll take a test run.
Well then! See you again!
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