Work at the rental pit on 2023-03-27 – Synchronization of the FCR carburetor and spark plug replacement were completed.

Work at the rental pit on 2023-03-27 – Synchronization of the FCR carburetor and spark plug replacement were completed.

Recently, I finished replacing the front tire of the CBX1000. Today, I completed the synchronization of the FCR carburetor and replaced the spark plugs. After that, I performed synchronization once more. I also prepared for an oil change, including replacing the oil filter and draining the oil.

The next tasks are to replace the clutch outer with a later model and to change the countershaft seal. These tasks cannot be done without draining the oil. I don’t have the concentration to finish all the work in one day, so I will proceed slowly, step by step. There is a lot to do, including removing the engine guard from the CBX1000, loosening the chain, and removing the clutch cover.

I find it easier to focus on FCR carburetor tuning. For my CBX1000, I perform an oil change once a year. Due to focusing mainly on maintenance and FCR carburetor tuning, the mileage hasn't increased much. For me, the time spent disassembling and cleaning is longer. I’ve made some new discoveries during this work, which I will write about.

So, let’s get started!

I feel like I made a new discovery during the synchronization of the FCR carburetor.

I perform synchronization of the FCR carburetor once a month. Sometimes the accuracy is not very high. I've noticed something this time. Before starting the work, I replaced the vacuum release plate. Replacing the vacuum release plate necessitates synchronization work because you have to remove the synchronization screws and nuts.

The synchronization seemed to settle quickly this time. I'm not sure if this is due to the new vacuum release plate. Usually, I would do synchronization work based on the previous adjustments. This time, I reset everything: the synchronization screws, synchronization nuts, throttle cables, and idle stop screws, before performing the synchronization.

Surprisingly, the synchronization was completed quickly. If there is significant deviation, it might be more efficient to adjust the synchronization nuts and screws to the standard values first.

This is true not just for motorcycles, but tasks that turn out to be easier than expected often provide good cost performance and quality. Previously, it was possible that issues with either the vacuum release plate or the lip seal were causing difficulties with synchronization. The lip seal didn’t appear to be very degraded visually.

It’s possible that the lip seal was a factor in why past synchronizations were difficult to achieve. The next synchronization should be much easier to get right.

Spark plug replacement completed.

The spark plugs have been replaced with iridium plugs with the gap adjusted to 1.3mm.

I found two important things in this task:

1. Remove components around the spark plugs, such as the engine guard and ignition coil, before starting the work.

2. Use a blower or similar tool to thoroughly remove any debris before proceeding.

Regarding the first point, not removing these components can lead to human errors like stripping the plug hole or failing to properly tighten the spark plugs. Although it adds a bit of extra work, it doesn’t significantly increase the total time due to improved efficiency.

The second point concerns debris falling into the plug hole, such as washers or nuts. While small particles that can be burned off aren't a problem, losing a washer or nut into the plug hole can be disastrous. Make sure to clean thoroughly with a blower to avoid such issues.

I may have dropped an aluminum spacer into the plug hole…

During the recent work, I was extremely anxious because there was a possibility that an aluminum spacer fell into the plug hole. I found 3 out of 4 spacers that had fallen from the ignition coil, but I couldn’t locate the last one. I removed all the spark plugs, inspected the plug hole with a microscope, and hand-cranked the engine to move the piston and check. There were no foreign objects inside, but just the suspicion was unsettling.

According to a motorcycle shop, if foreign objects fall into the combustion chamber, you can usually hear abnormal noises right away. In the past, a 6mm washer was found embedded in a piston. Objects that can be attracted to a magnet are easier to recover, but aluminum and similar materials are much harder to retrieve. Please be cautious.

mportant things should be written twice: Exercise the utmost care when removing and installing spark plugs.

Since it is important, I will write it twice: Be very careful about foreign objects falling into the plug hole.

To ensure I don’t make the same mistake, I’m writing this out to stimulate my memory. Falling objects into the plug hole are entirely a result of human error due to neglecting proper precautions. There are no elements of chance or bad luck involved; it can be prevented entirely.

I recommend thoroughly checking your work area and your clothing pockets, and taking your time with the task to avoid rushing.

FCR Beginners: Is a Fan Necessary for Synchronization Work?

This time, since I was working at a rental pit, I used a fan for the synchronization work. Normally, when I perform synchronization in the mountains, I don’t use a fan. Instead, I monitor the oil temperature and stop the work before it reaches around 80°C.

There is a difference between 80°C while riding and 80°C while stopped. For me, if I want to achieve high precision in synchronization work, I use a fan. Even though air-cooled engines are durable, maintaining high temperatures during idle is not pleasant. Additionally, when the oil gets too hot, its viscosity decreases, which is not ideal.

It’s challenging to determine exactly how much caution is needed and in what manner. However, if synchronization becomes too difficult, it may be necessary to wrap up the work reasonably. Although synchronization work rarely leads to the inability to ride, it can sometimes cause difficulties in maintaining idle speed. In such cases, adjusting the idle stop screw to lower the RPM can help.

For outdoor synchronization work, it’s best to complete it before the oil temperature rises too much.

Work at the rental pit on 2023-03-27 – Synchronization of the FCR carburetor and spark plug replacement were completed.【summary】

The remaining tasks are oil-related:

・Replacing the countershaft seal
・Upgrading the clutch outer to a later model
・Installing the dashcam

If there are no issues, I will complete the work with a test ride and final adjustments. However, if any problems arise, additional work to remove and return to the original state may be required. I will proceed calmly and carefully to avoid mistakes and complete the tasks successfully.

There is a motorcycle event next Sunday, so I will work to finish everything in time.
See you again!

CBX1000 – Work Photos

I haven’t been able to take photos of everything, but I will share photos of key points. Please refer to the captions for details about the content.