Keihin FCR jetting diagram

[dimora]

I thought some of you might like to see this if you haven't seen it before:





Note: "Fuel Screw" and "IMS (Idle Mixture Screw) are the same thing. Keihin uses the terms interchangably depending on what information you are reading.





Part numbers for different needles:



Sudco Part numbers:



Main jet part numbers:



Here is a great webpage detailing the location of all the jets and adjustments on FCR's - I'll do the same with my bank of 39's (with better pics, of course) when I pull them apart next time (should be next week - I'm going to skinny up my slow fuel jet just a bit and give them their annual cleaning).

http://www.ducatitech.com/2v/inside_fcr.html

Since this is stickied now ...here are some shots of the innerds of the beasties (Keihin FCR39 flatslides)

Underside of carbs with bowls removed...you can see the emulsion tubes (8MM unscrews them) and the main jets (6MM unscrews them). The lone silver rod is the accelerator pump actuator.



In this shot, the brass is the main nozzle tube with a main jet screwed into it.

Other holes (in relation to brass you see) are the pilot fuel jet at the 7:00 position and the Idle mixture screw at the 3:00 position. There is no jet in the hole at the 12:00 position. The float needle is at the far left.



Another shot of same with flash so you can see the pilot (slow) fuel jet. I have already removed the Idle Mixture screws in this shot:



Here is a shot of the top of the carbs where the needles live:



Close-up of screw that holds needle in place:



Screw removed, showing top of needle and the C-clip. Notice - no plastic spiders, springs, rubber diaphragms, or other crap to mess with. Simplicity at its best. I LOVE FCR's.



Here is a close-up of the pilot (slow) fuel jets. Location documented in above shots.



Closeup of the main nozzle tubes (these screw into the carbs, then the main fuel jets screw into these). Main fuel jets partially in view at top of shot.



Closeup of the main fuel jets. Emulsion tubes partially in view at bottom of shot.:



I use small needlenose pliers to remove the needles:



Like this:



Here they are removed:



Here is a view of the back of the carbs...you can see the red plastic intake trumpets, and two brass jets at the base of each spigot. The brass thing on the left base of each is the slow air jet (it is a spring loaded screw) and at the right base location is the main air jet:



Close-up. Again, slow air jet on left (adjustable spring loaded) - main air jet on right (choose a fixed number):



Accelerator pump actuator rod:



A ball-socket allen wrench is a must-have to undo the screws that hold the trumpets on - that or you can Z-bend a normal allen in your vice. 4MM is the size:



Close-up of slow fuel jet removal:



Close-up of main air jet removal:



A can of carb soak for making all those giblets I removed look new and clean again:



All shiny and sparkly again...now I just shoot carb cleaner from a can through all of them before re-installation.





Here are my aftermarket stealth racing adjustable Idle Mixture fuel screws:



As far as cleaning the carb bodies themselves...I jam the slides open with a screwdriver, protect the bike's faster green paint with lots of towels, and then spray carb cleaner into all the holes:

1) Main jet/main nozzle tube hole
2) Pilot fuel jet hole
3) Idle mixture fuel screw hole
4) Slow air screw hole
5) Main air screw hole
6) Other hole next to main jet / main nozzle tube hole that doesn't have a removable jet that lives in it.

7) I make sure I see a nice stream of carb cleaner come ouf of the two holes that are in the base of the carb throat.
8) I dis-assemble the accelerator pump and clean it as well, being careful not to lose the two rubber O-Rings or the spring. I have contributed to another thread with lots of pics on accelerator pump mods here:

http://zrxoa.org/forums/showthread.php?t=168688

Avoid getting carb cleaner on your FCR39 logo - it will destroy the paint and you will have to have Giannis make you a new custom one. Ask me how I know this.

[beantown]

Great

[dimora]

My first post modified with LOTS of new pics I shot yesterday.

[dimora]

Shamelessly stolen information compliments of Seth (SCS) from this thread:

http://zrxoa.org/forums/showthread.php?t=163418

58 pilot jet 3 or more turns on the air screws
55 pilot jet 2-2.5 turns on the air screws
52 pilot jet 1.5-1.75 turns on the pilot screws
50 pilot jet 1.25 turns on the pilot screws
These were my observations when setting up fcr39's

I wanted to stick it here so this can kind of be a "reference" thread for diddling these things - and Seth is the man when it comes to diddling FCR's.

[scs]

Shamelessly stolen information compliments of Seth (SCS) from this thread:

http://zrxoa.org/forums/showthread.php?t=163418



I wanted to stick it here so this can kind of be a "reference" thread for diddling these things - and Seth is the man when it comes to diddling FCR's.

i like to diddle other things too

excellent thread Shane

[dimora]

Parts diagram and part numbers from Sudco.

For what it is worth, I order all my FCR parts from Buzz at Dynoman.net








I got it all from here (Entire Sudco catalog in .pdf)

http://sudco.com/vol34/sudco34cat.pdf

[scs]

Parts diagram and part numbers from Sudco.

For what it is worth, I order all my FCR parts from Buzz at Dynoman.net

+1 for Buzz

[sillyhillbilly]

do you know of anybody who can translate these OEM pages, I really would like to know what extra things they may( or may not ) tell us





















there are over twenty pages in all

[sillyhillbilly]

please does anyone read japanese?

[rxrated]

I don't Marvin but I wanted to give a big thank you to Shane...Excellent work on this thread..ESPECIALLY since I put my FCRs on the bike this afternoon
*Thread elsewhere..*

[dimora]

I don't Marvin but I wanted to give a big thank you to Shane...Excellent work on this thread..ESPECIALLY since I put my FCRs on the bike this afternoon
*Thread elsewhere..*

Outstanding!

Now, you MUST add the stealth racing accelerator pump mod. It virtually eliminates bogging down low when you turn the throttle too quick.

[rxrated]

:LOL: Lemme get up to speed first ...
( I saw that in your thrread) Dang mods just NEVER end

[SKIDMARK]

Spray carb clean or spray brake clean and item 22 don't get along.

[mudnducs]

Spray carb clean or spray brake clean and item 22 don't get along.

Did you "melt" something Charlie?

[retcol]

That was one of the very best pictoral presentations on the layout of carbs that I yet to see - excellent presentation, now I know where all the jets are located. Honestly, before seeing your photos, I really didn't quite know where the jets exactly were. Thank you for going to all the trouble of taking and posting those great photos.

[SKIDMARK]

Bill I didn't have a melt down but the seals got all wrinkley and expanded to magnum perportions. Luckly there were spares in the misc parts bag. Saved my bacon.

[mudnducs]

Bill I didn't have a melt down but the seals got all wrinkley and expanded to magnum perportions. Luckly there were spares in the misc parts bag. Saved my bacon.

You must be charmed.

Sure looking forward to seeing you again this June Bubba.

[bacaruda]

Do you have a picture of how the carb vent's are routed on your FCR's?

[SteddyTeddy]

Just run them down along the frame rails or up under the seat. No biggie.

[flying dave]

Edit: Disregard. I figured it out....

Shane, thanks a ton for taking the time to do pics and whatnot in this thread.

[dimora]

Do you have a picture of how the carb vent's are routed on your FCR's?

I tuck mine into my Ted's battery "GET THE F*%& OUT" kit...you want to protect the ends of the vent hoses from vacuum (IE direct air stream as you ride the bike) as that can cause surging. In fact, on ANY podded bike, regardless of carb type, that is the normal cause of surging - vent-tubes being exposed to the airstream.