FCR carburetor – lip seal replacement

FCR-Negative pressure outlet nipple CBX
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FCR carburetor – lip seal replacement

I replaced the parts of the FCR carburetor that I was concerned about. Around the lip seal and accelerator pump.
CBX is based on riding, so I try to avoid long-term immobility.
Either you can finish it in one day, or you can remove the cab as an assembly, fix it at home, and reinstall it as an assembly. Since it is stored in a rental garage, it cannot be left unattended. In other words, it cannot be left in a state where it cannot be pushed or pulled, or in a dangerous state, or in a state where there is a possibility of it falling off. Basically, I rented a rental pit for a day when changing the oil.
Work diligently.
This time, I touched the FCR carburetor when I rented a rental pit, so I will post about it.

FCR-For Beginners-Lip Seal-Synchronization

Replacing the lip seal requires synchronization work. I don't have a synchrometer. There are high hurdles for beginners, such as not having a vacuum gauge. I took this opportunity to purchase a vacuum gauge, drilled a hole in the spigot, and installed a negative pressure extraction nipple...the hurdle was a bit high.
You can also put something between the throttle valves and time them to release at the same time, or you can measure the height of the slide valve with a tapered ruler. People who don't have equipment usually don't run in perfect synchronization, so just getting them roughly in sync can make a little difference. It will never break.
If you want to be perfectly in sync, collect the goods and take on the challenge.
If you're going to buy tools, it's better to buy specialized ones rather than half-baked ones.
As an example, I was working by connecting four vacuum gauges,
Currently, I bought two 4-unit vacuum gauges and converted them into a 6-unit vacuum gauge.
The price has doubled, but the work efficiency and accuracy are completely different.
The frequency of use of the vacuum gauge is high if you set it up yourself.
If you are a beginner, you should touch the carburetor a lot until you get used to it.
Tools and jets are a big expense.
Once you have everything together, the range of tunings that can be made with the FCR carburetor will expand.
Operation check of new lip seal of FCR carburetor
FCR-Taper Gauge
FCR-Taper Gauge
FCR-Taper Gauge
FCR-Taper Gauge
Before I start tuning, I check the approximate height of the slide valve and make sure it's not too far off. This d is also quite different. It would be nice if the error was within 0.5mm, but a gauge like this cannot measure with such precision. Measure roughly.

FCR carburetor – lip seal replacement main part

I have never replaced it, so I will replace it. The manual says to replace this part fairly quickly, but I've never replaced it.
There are probably many riders who have never replaced it.
At first, I thought it was a part that didn't need to be replaced.
However, once you begin to understand how the FCR carburetor works, you will realize that it is a part that should definitely be replaced.
This is an important part of the FCR carburetor.
There is a direction, so be careful.
FCR-Lip Seal
FCR-Lip Seal
This is a photo that I kept for my own work.
This direction is probably correct, so
If you are unsure of the direction, please use this as a reference. The small O-ring (correctly speaking, the U-packing?) of an FCR carburetor also has a different orientation, and the diaphragm of the accelerator pump also has a different orientation, so make it a habit to check and take photos before disassembling them. It might be better to keep it.

FCR Carburetor – For Beginners – Accelerator Pump Diaphragm

The acceleration pump adjusts the firing timing with a notch in the main body. The amount is adjusted with a diaphragm.
There are many other theories and theories as well.
At first, please adjust the notch with a 1.2mm signage gauge and set it to the default value.
If you touch the accelerator pump carelessly, you will not be able to set it.
It's not that you won't be able to set it in a physical sense, but that you won't be able to set it with the human eye.
If you want to turn it off, you can do so by using a stationery clip or the like to avoid pressing the push rod.
There is no need to change the amount of application unless you are a single person.
Once you decide, we don't recommend changing it until you get used to it.
Think of the accelerator pump as a seasoning after tuning is complete.
Changing the accelerator pump will increase or decrease the time it takes to reach the partial air-fuel ratio from the accelerated air-fuel ratio.
However, there is no need to stick to partials for the initial tunings, and there is no need to be fooled by the numbers. If you follow the numbers, you will be concerned about the partial air-fuel ratio, and you will end up with a tuning that has a low acceleration feeling in the eco mode specification. By the way, I reduced the amount of application from the accelerator pump and paid close attention to the partial air-fuel ratio numerically, making it an eco-spec motorcycle, which I'm really reflecting on lately.

Acceleration pump diaphragm replacement

FCR-Acceleration pump diaphragm
FCR-Acceleration pump diaphragm
FCR-Acceleration pump diaphragm
FCR-Acceleration pump diaphragm
FCR-Acceleration pump diaphragm
FCR-Acceleration pump diaphragm
The side with the stamp on the diaphragm will be on the ground side when installed.
Please note that there is an O-ring on the lid side as well.
By the way, this is a photo of me replacing the diaphragm with Kawasaki's KLX400 and KLX250.
The application amount of the accelerator pump is reduced.
I have been tuning up this accelerator pump for the time being. It is now the standard.

Negative pressure outlet nipple

It is attached to the spigot as an afterthought. Rather than capping or removing the nipple,
It is used as a balance pipe. I don't know how effective it is.
I'm sure it will be effective.
This is a combination of 1 and 6, 2 and 5, and 3 and 4. I don't really know what to do with the 3 cylinder carburetor.
When you order an FCR carburetor from Bito, you should probably be able to have all spigots processed like this from the beginning. In my CBX, negative pressure extraction nipples were installed on Nos. 3 and 6 from the beginning.

FCR carburetor – lip seal replacement【summary】

This photo was taken when I didn't know much about FCR carburetors.
Please take a look at the photos and use them as a reference when doing your own work.
Well then! Have a good FCR carburetor life!
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