Keihin FCR Choke Details

Because the Keihin FCR carburetor has an accelerator pump Keihin feels that a choke mechanism is not neccesary.

Heres why.

First of all a choke is a feature that creates a rich condition. This can be created by:

• Blocking off the air flow (Choke Plate)
• Increasing the fuel flow (Enrichment Circuit)

The accelerator pump is a feature that activates by actuating the throttle mechanism which in turn pushes down a bellows diaphragm with fuel behind it and is fed through a very small orifice to be squirted down the throat of the carb and mixed in the venturi. This accelerator pump when "nursed" will be enough to keep the bike running while cold till it gets to operating tempurature just like a choke would. However you will have to nurse the throttle a bit to keep it running. More so the colder it gets.

The FCR's Enrichment Circut (if available) opens a passage that allows a bit more fuel to be introduced and stays on until that passage is closed by disabling the "choke".

If you really want a choke on a multi cylinder carb you have three choices.

1. Use a choked carb and an unchoked carb. This would be an easy inexpensive for a twin carb bike. However for a 4 cylinder it would not be effective enough to wake it up and you would still be nursing the throttle. Understand that with the choke on only that cylinder would run rich and it would sound uneven until full operating temperature was realized and the choke disabled.
2. In theory (this is a BIG disclaimer) looking at the FCR with choke photo below I can see that "IF" you used a Keihin CVK carburetor with the same spacing as the FCR spacing you are building for your application, and used some good machining skills there seems to be enough similarities in the FCR's castings to be able to mount the CVK multi cylinder choke assemblies from a side pull choke from that CVK. Please understand that these Choke parts would be totally OEM only and we offer NO support in finding these parts to make it work, racking of this solution etc. Again.. this is theory.
3. Give it up! Cant be done.

This is how a choke type Keihin FCR Single would look like. This one happens to have a vacuum port that can be used for synchronization, and or a vacuum petcock.
Heres an example of a built rack of FCR's with the choke bosses exposed.
Stock Keihin CVK Choke Assembly from a ZX10 Ninja. Many 90's Kawasakis use the CVK carb with this choke mechanism. You could go to kawasaki.com and dig your way down to the parts drawings and find a carb with the right carb/choke parts. That info could then make you feel comfortable in finding a salvage carb in the salvage, used, forum environments. Good luck!