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.
About taper angle and FCR tuning – MJ confirmation from test run – How much does MJ influence? 2022-08-20
Today is Saturday, so I wanted to ride on the CBX1000, but unfortunately it looks like it's going to rain. To shake or not to rain? Anything else? It was a subtle sky pattern. I ended up doing a test drive around my house while checking the weather forecast on my smartphone. So, I will be doing a test run mainly to see how the MJ looks after changing the tunings from last time. In conclusion, there doesn't seem to be any particular problem, so I'm putting the MJ change on hold. Current tunings SJ-42 PS-2.20 minutes return AS-2.10 minutes return JN-90FXM#2 MJ-128 Uotani ignition timing [1] Acceleration pump diaphragm is KLX250 Discharge timing is 10mm
It becomes. It gets leaner in the winter, so I'm thinking that I can keep the SJ as it is, or change it from 42 to 40, but I want the jet to be as rich as possible, so I'd like it to be as rich as possible. uses 42.
MJ’s influence range
FCR-MJ renge
Looking at the range of influence in the manual, it says that it only affects up to 1/2 of the throttle opening, but it feels like it affects up to about 1/4 every time. When you change the first position, it seems like there is about a 15% change from the previous time, but in my experience, I rarely feel a big change. Maybe it's a placebo or I'm too scared to twist the throttle all the way, but it's hard to feel the difference when driving at full throttle.
Change at about 1/2 throttle opening
It is easy to feel that if you make MJ extremely large or small, it will greatly affect the increase in throttle work at about 1/2. It is not a good idea to set the throttle opening to around 1/2 using only MJ, but you may enjoy the change to an interesting degree. It may be a good idea to set the throttle opening to about 1/2 to 3/4 at MJ, assuming that you will not open it fully on public roads. This needs to be considered in combination with the number of clip stages, so if you increase MJ, you may need to try raising the number of clip stages upwards. It is written in the influence range of the manual that you can adjust the change with the JN taper angle, but even if you change only the taper angle, the appropriate clip position will also change. Overall, the tunings feel like they need to be redone. When touching the taper angle, you need to keep in mind the number of clip stages, and also check whether it is within the range of standard stock in the manufacturer's stock. For large bodies, rather than choosing the taper angle, it is better to adjust the number of clip stages. It reads as implied by the manufacturer. If you are using FCR, you will definitely have trouble when choosing a JN jet needle, so please take a look. Especially if you are using a small body FCR, there may be cases where you cannot get the JN of the desired count. It appears that BITO, a KEIHIN distributor, has changed the initial shipping JN about 3 times for CBX1000. At present, only BITO probably has JN in stock. 90FXM#3 should be installed as the initial value. *It looks like it was 90FTM and 90GTM in the past.
The following is my guess after actually measuring the thickness of JN. It is unclear whether this is correct or not.
90ETM#1 = 90FTM#3 = 90GTM#6
If you only look at the low opening, it will probably be about the same.
There is no need to consider changing the number of clip stages for straight diameters. There is a difference of about 1 clip stage for a straight diameter of about 6 stages.
When selecting a jet needle, please take into account the limited lineup of standard stock that can be cut up. It's a rough measurement, and the thickness of JN varies depending on the height. Recently, I have been mainly thinking about changing the taper angle by changing the number of clip stages. I think it would be difficult to change just the taper angle, and it would affect the overall feel of the JN. I have not thoroughly tried various taper angles, so please understand if the information is incorrect.
CBX1000 Photos
Whenever I feel like it, I try to touch it or go for a run, but lately I've been feeling a little sluggish, probably because of the heat, so I'd like to try riding early in the morning or in the evening in the summer.
For FCR beginners – JN clip stages and standard stock
If you change the number of clip stages without getting caught up in numbers such as air-fuel ratio, your motorcycle will change into something different in an interesting way. It's an easy-to-understand area of influence, so please give it a try.
The number of clip stages can be selected from a total of 7 stages.
If you can find a position where it will not blow up at that time, please remember this as the lower or upper limit of the number of clip stages. From now on, you should be less likely to touch anything above that clip level.
When changing MJ or straight diameter, it may exceed the upper or lower limit, but it should not exceed it by much.
Then, if you check the standard stock of JN, you should be able to find the appropriate taper angle and cut up for your JN. Judging from the tuning manual, the straight diameter can be adjusted to some extent by combining it with SJ.
Start with the pre-tunings shipped by the manufacturer or the tunings provided by volunteers who have published their data on the web, and perform AB tests one by one to determine the best tunings for your motorcycle. When you purchase JN, you will purchase several bottles next time. Just be sure to check what number the standard stock is. It's definitely helpful.
↓The active jet needle page will open in a new tab. ↓
About taper angle and FCR tuning – MJ confirmation from test run – How much does MJ influence? 2022-08-20【summary】
The story has gone off the rails quite a bit, but MJ is the only one touring, so I'm sure you'll have a lot of fun even if you change it up. Nowadays, it's good to ride alone, but it's better to ride with two or three bikes because it's easier to compare whether your motorcycle is doing well or not.
There are many new things I notice when I ride with other riders. When I run alone, I try to check various things.
I'm sure everyone is busy tuning up FCR.
Please be careful of heat stroke and enjoy FCR life.
See you again!
