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.
FCR Tuning – Adjust the air screw with a digital tachometer – 2022-11-10
I did a light test run today. The purpose is to finely adjust the position of the air screw and pilot screw. There's something I wanted to try that was incidental to this. Until now, we had determined the position of the air screw based on a test run. Of course, I also use the air-fuel ratio meter as a reference. However, the air screw position was basically determined based on a test run. I recently purchased a digital tachometer. The accuracy itself is low, so it's hard to tell if the numbers are correct, but I'm thinking of using it as a gauge, relying on the increase in rpm.
It is indicated by clock hands. 90 degrees = 15 minutes
[Measurement method] ① Return the air screw to 1.0 for each cylinder. The premise is that the screw position is correct above 1.0. ②Lean for 5 minutes on cylinder 1 ③ Find the return number that increases the rotation speed ④Once you find the appropriate return position, return to 1.0 ⑤Search for the appropriate return position with No. 6 cylinder
I decided to match it on the lower side. You can do it on all cylinders, but Basically, it is assumed that there is no 15 minute difference, so The return is the same for all cylinders. There is probably a difference of about 5 minutes between each cylinder. It may be off by up to 10 minutes. Due to work time constraints, I decided to take the average and made the same adjustment for all cylinders. To begin with, I can't hear any changes to my ears. The result is 1.20 minutes back. I tried the pilot screw from 0.45 minutes and set it to 1.00 minutes using the air-fuel ratio meter as a reference. Before adjusting the screw, the engine startability when cold was 1.15 minutes, which was quite good. I will check the engine startability when cold again at a later date and make a decision. There are almost no changes to the screw return before and after. I think the level changes every day depending on the weather and humidity that day. I would like to set the pilot screw back as much as possible from 1.00 minutes to 1.15 minutes. I feel like the screw changes become slower after 1.30 minutes. On the other hand, when the time is less than 1.00 minutes, I feel that the change in the screw is very large. The introduction ended up being a bit sloppy. I will write about tuning etc.
I am changing the jet needle, JN-90FXM#3 and JN-90FTM#1 are being changed based on the idea that they are equivalent. The sense of acceleration is also perfect. When things are not going well, it may be because the accelerator pump is too effective. One of the real pleasures of FCR is being able to effectively use the accelerator pump. I would like to increase my experience value by making various changes.
Impressions from the test run after adjustment
In particular, the ride taste has not changed. The cold start before adjustment was quite good, The low throttle opening was also quite good. It just becomes lean at the moment of acceleration. This is the range that can be accommodated by the gear position. Tomorrow, if I look at the cold starting performance and find that it is comparable to today, I will settle on the current tuning for low throttle opening. Next, select the main jet. You cannot open the throttle fully often. I think that you can only see the acceleration feeling at 1/2 throttle opening or up to 3/4. The main jet hasn't moved much. Take the time to check and make adjustments when you can drive at full throttle.
For FCR beginners – Instruments are necessary for tuning
There are some people who say that you shouldn't try tuning unless you have some experience. Experience is a great weapon, but you can't become an experienced person unless you go through the ranks of amateurs. Measuring instruments such as the air-fuel ratio meter and this time's digital tachometer are tools that are much more useful than those of experienced riders. It is unclear whether the measuring device is showing an exact value, but it will show a value close to the exact value. It is clear how much has changed between before and after. Measuring instruments have a sensibility that exceeds the experience of a veteran. Even amateurs can read numbers. I believe that the more amateur you are, the more you should rely on measuring instruments. If you can tune without relying on measuring instruments, you are already quite an expert. Since you are an amateur or a beginner, you should rely on measuring instruments. If you are no longer satisfied with tuning to the best of your ability, try buying measuring instruments little by little. I'm sure tuning your FCR will be fun.
FCR Tuning – Adjust the air screw with a digital tachometer – 2022-11-10【summary】
This time, rather than determining the proper position of the air screw on a test drive, I worked on the premise that the return position of the air screw was correct when the digital tachometer was raised. It didn't look bad after a test run. However, the engine is already warm by the time you start touching the air screw. I would be very happy if the cold startability is good tomorrow. You will be able to find the correct screw position without a test run. I think it depends on a case-by-case basis, but there are ways to do it that are not that far off. Once the tuning is decided, check the synchronization again. We will clean up and welcome 2023. I hope you all have a fun FCR life! See you again!
*Photo gallery is posted at the bottom.
CBX1000 photo on 2022-11-10
Candy red seems to fade in the evening. There are two sets of exteriors, but for some reason they are red and one is red, so there are many things I should have thought about a little more before ordering the paint. I like red CBX1000. Please find what you like about your motorcycle.
