I am the owner of a Honda motorcycle [CBX1000] who lives in Hiroshima City, Japan. I am posting about FCR carburetor and CBX1000 customization. I also post about things other than cars and motorcycles. We will post information that will make bikers around the world happy.
The surprising moment when I tuned my FCR by myself – for beginners – Good things
It's been about two years since I started tuning the FCR of the CBX1000 in earnest. It's a new year. There have been times in the past when I was tuning the FCR that I was impressed with. I'll write about some of the surprising moments from the past. This blog post will mainly focus on the good things. Riders who are thinking about starting to tune their FCRs in earnest should use this as a reference. For beginners, tuning the carburetor is more frightening than making it better, as it can cause problems. I think I was the same at first. If it goes bad, who's going to fix it?... A small thing won't stop it from running or cause the engine to burn out. There are many predecessors who will teach you on social media. If the demand for FCRs increases, the lifespan of disappearing technology will be extended, which will benefit all FCR users. If you're in trouble, someone will surely help you or at least provide you with information. Please feel free to disassemble the FCR. The things I'm going to write about from now on are all things that are easy to imitate and the changes are easy to understand. Now, I'll explain the surprising points of FCRs for beginners.
First, the first thing a beginner should do is change the number of clip stages of the jet needle. The parts that are easily accessible to the FCR are the pilot screw, idle stop screw, air screw, and acceleration pump timing adjustment plate. The number of clip stages of the jet needle. The easiest tuning of the above is the idle stop screw. It only changes the idling, so you won't be impressed or surprised. For motorcycles with two-pronged throttle cables like my CBX1000, I don't even want to touch the idle stop screw. It's a little more difficult. Next is changing the number of clip stages of the jet needle. Disassembly is included. There is no need to worry about not being able to put it back. Changing the jet needle itself is also a low hurdle. However, selecting the jet needle is difficult. Just changing the number of clip stages by one stage can make a surprising change. Change the position of the clip when the seasons change. If something seems strange, just return it to its original position. Once you get used to changing the jet needle clip, you'll want to try changing the straight diameter next. Changing the jet needle is just expensive, but the hurdle is low. The good thing about changing the jet needle is that you can quickly return it to its original state. The initial straight diameter will probably be [M]. You should initially purchase [N] or [P]. This is in the lean direction. If the jet needle is not too far off, any slight deviations can be covered by adjusting the air screw. Purchase rich and lean, one size at a time, and learn how to adjust the air screw. The pilot screw only needs to be touched when changing the slow jet. If pre-tuning is done, you don't need to worry about it too much.
②The moment the main jet number was decided
The acceleration feeling at 1/2 to 3/4 throttle opening has improved like nothing else. The main jet may not be the only cause, as it also depends on the jet needle. When I started tuning it myself, the number was 105, but I gradually changed it to richer, and I noticed a change at around 130. I realized that the main jet has an effect even when it's not just at full throttle. Before changing the main jet, I changed the slow jet from 35 to 52, and did many test runs, adjusting the screw every 5 minutes.
③The moment the slow jet size is increased too much
I was surprised when the throttle response improved when the slow jet was increased from 45 to 52. I had set the jet needle quite lean, so perhaps the slow jet should have been set in the richer direction. Maybe I had tuned it in the wrong direction and it ended up being tuned properly. That was the moment I realized how much of a difference a slow jet can make. At the time, I had an air-fuel ratio meter attached to the CBX1000, so I tried to set the air-fuel ratio at idling to 12.9, even though I didn't know what to do. No matter how many times I tried this, the screw position that gave good starting and smooth starting was when the air-fuel ratio was around 12.9. The sense of power improved significantly when the throttle was opened slightly from the fully closed position, about 1/8 to 1/4.
④The moment the acceleration pump discharge timing is changed
After tuning the accelerator pump discharge timing to a state where it was almost ineffective, I was surprised when I turned it on and compared when the accelerator pump was working and when it was not. I was surprised twice: when I realized how much acceleration the engine could achieve when the accelerator pump was effective, and when I realized how much damage the engine could cause when the accelerator pump was too effective. Either way, there are times when checking the effectiveness of the accelerator pump can surprise you in either a good or bad way.
⑤I wasn’t surprised that the synchronization worked so well…
I think it's a difference in feeling. Even though the synchronization was perfect, it didn't surprise me as much as the other items. When the synchronization is correct, there is a change in the idling sound and the way the rotation drops. Although the points are slightly off, what surprised me the most was that the new vacuum gauge was out of sync. Carburetor synchronization is an item that you should have experience with when it comes to maintenance. Until you are used to it, it's no problem to use a taper gauge or check visually.
Other mechanical changes
I have AS Wotani SP2 installed on my CBX1000, and through tuning the FCR and performing other maintenance, I have become more aware of changes in other parts, such as changes in the driving feeling when changing the ignition timing and the feeling when changing the brand of tires. I changed the plug wires and adjusted the plug gap because I didn't want it to malfunction, but I haven't compared the before and after clearly so I'm not sure, but since I started tuning the FCR, I have become more aware of the before and after.
FCR for beginners – Trying out an air filter
This is written for beginners, but it is even more beginner-friendly. I think about half of the motorcycles of owners who have aftermarket carburetors installed have them pre-tuned and installed at a shop. The red Velocity Stack probably remains attached at that time, right? Even if you don't touch it yourself, we recommend installing a Foam Air Filter Sock or a K&N power filter. Either one will not affect the tuning in the big picture. The Foam Air Filter Sock will get your hands dirty. However, you don't need any special tools. We recommend installing it as a DIY project.
The surprising moment when I tuned my FCR by myself – for beginners – Good things【summary】
I have written mainly about what I have noticed and discovered in a good way while tuning FCRs. Those who are just starting to tune FCRs will probably think in a similar way and make similar discoveries. One thing is certain: a motorcycle will not break even if an amateur touches an FCR. It would be more accurate to say that many people have not tried to tune FCRs or maintain motorcycles, rather than that they cannot do so. I think you may be worried about whether you can restore it yourself even if you disassemble it. Please consult a motorcycle shop about maintenance methods. If you ask a motorcycle shop where you should try to touch for DIY beginners, or if they will come and pick it up if you touch it yourself and it doesn't work, or if they will inspect it again after you touch it yourself, you should feel less anxious. Motorcycle shops are also in business, so I'm sure they won't be unhappy if you say you'll pay them. I think the best thing is for the popularity of motorcycles, including FCRs, to increase. If I receive a consultation, I may lend information and tools to those whose identities are clear. We would be very happy if people who have never done DIY or FCR tuning would take the initiative to try tinkering with their motorcycle themselves. So, we hope you all enjoy the fun of motorcycle DIY. See you again!
