Selecting a jet needle for the CBX1000 FCR model – I want to choose something other than the 90FXM

Selecting a jet needle for the CBX1000 FCR model – I want to choose something other than the 90FXM

The current CBX1000 FCR jet needle shipped by BITO is
90FXM#3. I called to ask.
90FXM is a special cut-out with an [X] cut-out.
Normally it is [T]. I would like to change the straight diameter in various ways,
but there are no options.
Even if you order a special order, the delivery time seems to be long for 20 pieces,
so realistically, you cannot choose the straight diameter.
If the cut-out changes, the basic position of the clip steps will change.

90FXM#3 = 90FTM#1

is the same tuning and jet.
In reality, it seems that tuning 90FXM#2 in summer and 90FXM#3 in winter is better for my CBX1000.

The standard stock lineup is the [T] series, such as 90FTM, but realistically, the clip stage will be higher in the summer, so you will only be able to choose the straight diameter in spring, autumn, and winter. If you change the straight diameter of the jet needle, such as making the straight diameter much thinner like 90FTR#2 and changing the slow jet from 42 to around 50, you may have to start over from selecting the slow jet. FCR tuning is the balance of each part, so you can tune it without using 90FXM. My current jet needle tuning is 90FXM#2 in summer and 90FTN#1 in winter. I think it's probably the same jet needle as 90FXN#3.

What if you want to change the straight diameter in the summer?

Alternative Option 1
[Tune using 90GTM#3]
This seems to have been the jet needle shipped by BITO before.
When the taper angle changes, the clip step also changes to a lower position, so the lack of clip step is resolved. However, the taper angle of [G] may not have been compatible with the CBX1000.
If there was no problem, they would not have shipped it with a special cut-up such as 90FXM.
*I called BITO again and they said that the [G] taper felt a bit strange, so they changed it back to the [F] taper and shipped it.

Alternative Option 2
[Tune using 90FTS#1]
This is a method of tuning by shifting the range of the straight diameter in the lean direction.
In the case of my CBX1000, I used to tune it with
JN-90FTR#2
SJ-52
. This was before I called BITO.
After calling BITO, I retuned it using 90FXM.
The disadvantage is that the SJ is larger than expected, but it is unclear whether this can be considered a disadvantage.
*When I called BITO again, they said they had not considered changes such as SJ.

If you want to choose a straight diameter in the summer, option ② seems like it would be fine.

I have not tried the [G] taper in ①, but I can imagine that it may be significantly better depending on the individual differences of the motorcycle. When choosing an [E] taper, start with 90EZM.

Custom Jet Needle

Basically, orders are made in units of 20. For special orders, the price seems to range from around 650 to 1,500 yen per unit (excluding tax). To be honest, it’s not realistic to pay 13,000 to 30,000 yen for something you’re not sure you can use. There are also other options, such as trying Yoshimura's MJN.

FCR may not be for beginners…Tuning with jet needle

My recent approach to tuning the FCR is to focus on adjusting the jet needle as much as possible. The other screws, like the air screw and pilot screw, are easy to access, so I prefer to leave the slow jet alone once I’ve decided on it.

As the title suggests, when you can’t select the straight diameter of the jet needle on a model like the 90FXM, you may need to change the slow jet instead. However, this isn’t the correct method because the slow jet can’t fully compensate for the range covered by the straight diameter of the jet needle.

Setting aside the fact that you can’t choose the straight diameter, tuning by adjusting the jet needle, which is easily accessible, will save time and reduce the risk of issues during installation and removal. If you have a variety of jet needles, you’re likely not a beginner. Tuning by changing the jet needle is also quicker.

Selecting a jet needle for the CBX1000 FCR model – I want to choose something other than the 90FXM【summary】

From a practical standpoint, it may be better to make the SJ larger for the CBX1000 and deal with it with the straight diameter of the lean. If the straight diameter of the jet needle is not perfect, there is a high possibility that the SJ will need to be changed and then retuned. This will eliminate the convenience of tuning just by changing the jet needle.
Today, I called BITO to ask if they have any other lineups besides the [X] cut-off,
and they said they don't. However, they said they will consider responding if there are many inquiries about tuning the CBX1000. It would be much more helpful for users if the agency had stock rather than ordering individually. Either way, carburetors are a dead or disappearing technology, so we can't be picky. I hope BITO will continue to make great products other than FCR. So, everyone, enjoy tuning your FCR without giving in to the cold or snow.
See you again!

CBX1000 Image Gallery

I'll just post a selection of some neatly taken photos from a previous post.