I have been getting quite a few PM’s lately regarding the Keihin FCR 40mm carburetor and installing it on a Z400. I have taken a few pics and written a small guide to help others with the setup and install.

To run this carb you need a few Honda parts. Order them from the folks at servicehonda for a good deal. www.servicehonda.com

1. Carb: 16100-MEB-671
2. Throttle Cable: 17910-HC5-970
3. You may also want to pick up a variety of jets including 42 pilot, 178, 180 and 182 main jets.
4* Honda thumb throttle Housing and Assembly: 15+ parts (best to buy on eBay)

*You can also use your stock Suzuki thumb throttle assembly by tapping it to fit the 10mm x 1.25 Honda cable.

note - the throttle cable mentioned above will work but needs to be trimmed. You trim the Black Cover and the spiraled metal that supports the cover (NOT THE ACTUAL CABLE) just the cover!!!! You are just increasing the length the cable can travel. Trim it right where above the adjuster bolt! you see where my bolt is all mangled??? thats where!!!! Here is a pic:



Once you get your throttle cable trimmed and installed make sure it pulls freely from all the way closed to throttle stop

The carb comes with a few extra features for the CRF450 that we don’t need or use. I put a vacuum cap over the hot start cable inlet and there will be an electrical connection for the TPS (Throttle Position Sensor) Just leave it alone and unplugged. This picture shows the hot start capped.



You also need to cap the back side of the Fuel Petcock, the vacuum hose that connects to the stock carb is not needed anymore and you don’t want dirt or any foreign objects getting in there. Here is a pic




Once you have your throttle cable and thumb throttle assembly setup and re-jetted the carb for the Z400 you are ready to install it on the quad. A good baseline setup for the jetting is 1.25 turns out on the mixture screw, #42 Pilot, 2nd clip from the bottom (closer to taper) on the needle, and a #180 Main Jet.

1. Remove your tank cover and side plastics.
2. Remove the gas tank
3. Loosen the clamps on the stock carb and remove it and the throttle cable.
4. Remove the rubber head to carb air boot with clamps loosened.
5. Work the boot onto the carb and tighten clamp (I have found this to me much easier to install and leave it on permanently. If you need to remove the carb just loosen the front clamp on the head and remove it with the air boot attached to the carb.
6. Install the carb and tighten the clamp on the head.
7. Hook up the airbox to carb boot, it will be stretch but will work and also will not go anywhere when tightened.
8. Once everything is tightened up good work the carb back and forth and make sure it will not loosen up under hard riding.
9. Now hook up your throttle cable and route it to the assembly if you haven’t already.
10. Install the gas tank and hook up the gas line. The FCR with a stock petcock needs to run in the PRIME position so fuel will fill the carb bowl.
11. At this time I would start it up and make sure it runs good. If everything is well finish putting on the plastics and ride!!!

MODS: Any chance of getting this post made a sticky or adding it to the Z Tech for everyone to use????

The baseline jetting is just a baseline. Once installed on your quad you should check it and adjust for your temperature and elevation.

I hope this helps! Also ... other FCR40 owners please chime in if I have forgotten something!!!

Excellent post! Yes this needs to be a sticky or in the Z tech spot. I have already printed this out and will be my guide for the installation of my carb when it gets here!! Thanx a ton!! :D

:)
Your petcock vacuum cover on the fuel valve is identical to mine right down to the color.

What bike is this from? I didn't see it on the 02 or 03 CRF450. I did see the 16100-MEB-670. Is this the same thing?

And for jets, do you order them from the 2002 450?

I just checked the service honda site and the 03 CRF450 Carb has a different part # ... 16100-MEB-771 and it has a cheaper price too. It also comes with a 42 pilot already, but a 170 main.

you can order the jets from service honda or also pick them up from a local honda dealer, just tell them you need them for a crf450

I thought I saw someone post about the on/off switch, making it have on off and reserve for this carb...add that in to the tech section too if you can find it...

Will a Terrycable throttle work with that cable? Or the Mooseracing one.

uncle, you wont want to have those other throttle cable.... because they are stiff as hell.... unless you like stiff thumb throttle, I would advise against them....

Ya, what he said.

The Terrycable is stiff?

Hey guys, DadsZ400 was able to convert his stock petcock to all for the selection of on/off/reserve!!! very good info!!!

http://z400central.com/invision/index.php?...showtopic=11761

So will the Terrycable throttle work with the cable from Service Honda? And are they really that stiff?

The Moose and Terry Cable are the same thing. Too stiff. Get a Honda 250R thumb throttle

I modded the honda cable that norcal gave the part # for. I pulled the end off at the lever end and cut 5/16" to 3/8" of the sheathing off with dremmel tool. Be real careful not to nick the cable inside. Cut the black plastic cover back a 1/4" from the same end and reinsert into the adjusting end. You can use a coax crimper to re crimp the end on the cable. I tapped the stock throttle assemble with a 10mm x 1.25 cutter after predrilling with a 11/32 bit. Use grease on the tap to collect the metal filings. Make shure to get all the metal shavings out of the tapped throttle assemble so they don't end up inside the cable. Connect the cable at the carb end first, then screw the new cable into the thumb throttle assemble and adjust. This worked real well and I didn't have to buy a honda assembly.
The carb came with a 45 PJ and a 175 MJ. I installed a 42PJ and left the 175 main in. With my set up it the carb worked pretty good . No bogging good throttle response and pulls real hard on upper end. The main jet still needs to be determined and I am going try moving the needle in different directions to help the mid response.
FYO: I have both cams, port and polish head, full yosh sys, K&N filter, no lid, stock bore and ride at seal level.

That's a sweet idea. I will probably be selling my Terrycable now, because I like the stock thumb throttle. Thanks for the tip!

Where did you get the blue and white caps from?


Lori

Any auto parts store should have the vaccum caps. I got mine from Pep Boys, but I dont know if you guys have that on the east coast.

bump

Whats the deal with the 4 vaccum lines? Can those just be plugged. I checked the one outlet on the left side of the bike and notice no air coming in or out of it. I've got all mine capped right now but don't know if it's causing me a problem.

When free reving i'm getting a strange hicup when i first slam open the throttle that will nearly stall the motor. When the motor in under load as in riding it's not really a issue.

It also feels a little flat up top and I have a 180mj in there. I think i'm going to try a 182mj and see if it helps any.

will add to Ztech/stick it in the performance section :)

Vaccume lines??
I think your mistaking vent lines... they drop out the bottom.

Free revving bog is caused by the accel pump puking to much fuel into the carb on rev. On a bigbore its not a problem, but with a semi stoce ont your better off to take a brass ball from a fan chain and pull the pump jet and drop the ball in their (making the jet a 0)
If it doesn't affect you while riding then don't worry about it.


Try messing with the needle before you try the MJ, that might be better for you.

Ok I put those lines back. Sure did look cleaner without them and just being plugged. Oh well, back to my problem.

I think your right in saying it's the accel pump causing me the problem. As long as I have the rev's above 2-3k and go WOT it's fine which in most cases where you are riding unless you really goofed.

I tried the needle all over the place and even went up and down mj sizes to no avail. I haven't tried anymore WOT runs since I had the mj at 180 but it felt a little flat up top with it. It wasn't stumbling or popping but it didn't feel even as good as the CV36. The mid rpm power felt GREAT, feels like i picked up a ton of torque.

You think I'm to lean there or to rich on the mj describing my condition above? I can obviously try both directions but rather go with a educated guess into which direction to go.

I was running a 175mj on the CV36 which is huge compared to what most run with it but it loved it with my mods. Any smaller and it just didn't have the same pull.


EDIT: Just reading on YFZcentral.com and those guys are complaing of the same issue even with a 439cc. So I guess it's "normal" and you have to live with it unless they make smaller jets for the accel pump.

I think your lean, but pull the plug and see, I'm running a 180 in mine, and its a nice brown color.

its not the accelerator pump although you can adjust it, they call it the "BK mod" over at thumper talk.

remember that with the FCR you are controlling the slide with the thottle cable and when you whip it from idle to WOT it will bog. Call James Dean or look for his posts around the net and he will say whatever you do it is not possible to eliminate the bog on a pumper carb.

you can snap the throttle open on the stock CV carb because the slide is actuated by vaccum and wont cause that bog. but it also revs alot slower and doesnt have the same performance of the FCR.

hold it a touch above idle and then pin it WOT and it will be perfect. the bog will never effect while riding or even at launch, just in your driveway ;)

i started out with a 182mj but plug was barley turing a lite brown so went to a 190mj but havn't done a re check but it ran sweet at both settings also went from second to third on needle from bottom i'm still at 1 1/4 on mix screw i'm in new hampshire at sea level if this helps anybody thanks to all for the help on carb settings and gas tank mod

You can shim the accel pump witha washer to make it pump less. Alot of carbs come set up that way (Sparks set mine up that way).
There is a aftermarket accel. pump cover you can get that will lean it out even more than a washer. see below...
There is also an adjustment on the wheel where you can change the leverage of the linkage to the accel. pump. Make sure you are at the smallest setting there first.
FACTORY RESEARCH & DEVELOP
13825 ALTON PKWY
SUITE # A

IRVINE CA 92618
Telephone 949-206-0894
They have a website, I am not sure what it is.

Would all of this information be relevant to the FCR 39? A simple yes or no will work. I tried to search for this info but itwont let me for some reason...thanks,

Jamin

Does Sevice Honda also sell a 39mm FCR? I so and you know the P/N please let me know. I have a 13.5:1 pistion w/intake cam and wood race....I believe the 39mm is the way to go to keep the low end on this set up right?

Anyone have a photo of the FCR 40 installed? I want to see the set up and how you ran the lines. Trim the vent lines?...leave them and run around something??

HA I'VE GOT THIS SAME SETUP BUT I WENT A DIFFERANT WAY
I USED THE STOCK CABLE & TOOK OFF THE END OF THE CABLE THATS ON THE CARB SIDE AND USE THE STOCK CABLE END OFF THE CRF450 CABLE, BUT TOOK A LITTLE FILE TO OPEN THE HOLE A LITTLE. SO, I GOT THE STOCK CABLE WITH THE END OFF OF THE CRF450 CARB AND THE BRASS RETAINER OFF THE STOCK Z CARB. THE BRASS RETAINER GOES ON THE CARB CAM. IT THREADS THE CABLE.


BUT THE TRICK THING I GOT WAS THE AIR BOOT OFF A 400EX.
JUST CUT THE AIR INLET OFF THE BOOT, & CUT OUT THE HOLE IN YOUR AIR BOX
IF YOU COMPARE THE TO AIR BOOT ( Z, 400EX) YOU WILL SEE THAT YOUR STOCK BOOT RESTRICK ALOT OF AIR.

So what filter did you use with the 400ex boot and how did you hook it up?

Is someone have picture of the 400ex air boot installed?

Do i have something special to do for installing the boot? Do i need to modify the stock air box?


Thanks! :)

anyone have a picture of this installed so i can see where all the lines are going?? and a picture of your throttle cable on the handlebars... thanx

I just bought this FCR 40mm carb and I am soon to purchase a bare performance aluminum airbox. What hoses do you guys use from the carb to the head and from the carb and from the other side of the carb to the bare performance airbox. thanks


ryan

are they the same thing...? besides the jets that they come with?

Update!!! I highly recomend getting the Honda cable from the Trx-450r pt num 17910-HP1-000. This setup works the best IMO. It fits perfectly in any Honda thumb throttle assembly. If you go this route you do not have to cut any cables or re-drill throttle assembly. I had the previous cable but it was a little too long and always stuck up out of the top of the handle bars, plus If you mess up when cutting it your screwed and have to buy another cable anyway.

Service Honda

da%@#$% I already bought the previous cable that I have to modify...
What does the previous cable ## actually fit?

I also have the '03 EX air boot, DRZE boot, the carb is a -771, JD jetting kit for a '03 CRF450, and a Kientech stainless extended fuel screw. I am going to the dealer to pickup a few pilot jets and maybe one or two pilot air jets.

I would like to replace the valve on the gas tank with an shorter profile non-vacuum aftermarket one with reserve, on, off?

The previous cable fits the CRF-450 and the carb you bought except that it has to be modified to allow for more travel. The cable I just posted does not.

i am going to get the FCR40 but i got confused reading all the things i need...


so what do i need and how much are they?
Carb-$300
trx450r-cable?
400ex-Thumb Throttle?
anything else?
what about the air boot?

Carb is $353 or so, cable is $15, and '03 Suzuki DRZE boot to cylinder head is optional as the stock one can be fitted but that is $15, then the 400EX boot '02 or earlier for about $15, then the thumb throttle is maybe $10 used or drill and tap the stock Suzuki one.

My test fitting:
I have an '03 EX airbox boot that I am trying, I recommend on using the '02 or earlier as this one is a PITA. If someone can show a picture of the earlier boot I can explain the differences. The only thing that is making the boot "workable" is the Houser Airbox spacer for the LT rear swingarm, this allows the boot to not kink as bad and you can angle the airbox for a better position. Another solution is to make a mod on the airbox side or with a small pipe section that will give you that extra 1/2"-1" that will allow you to use the stock intake hose, you can stretch it to reach the FCR40 but run the risk of it popping off the box. Later on I might try to fab up my own intake pipe between the carb/box out of aluminum. I don't know if any of ya'll noticed this but the FCR40 was hitting the top engine bracket mount, this can be solved in two ways. The first one is to grind down the engine mount bracket, this is easiest. The second would be to toss the OEM mount and to fab up another that takes up less space and would be a bit lighter, this requires a little more use of the brain matter and is a bit more difficult.

so if I buy a FCR39 off a YFZ, and I don't want to mod my throttle......

do I have to buy a YFZ thumb throttle? Or will a honda (450R or 400EX) thumb throttle assembly work as well???

Yes, you can use a Honda thumb throttle off a 400ex, 450r, 300ex, 250x, recon, etc .... i think any 4 stroke will work.

So, do you just zip up the hoses. No one has answered about what to do about these. :wtf

Those of you who bought a honda throttle assembly, how much did it cost. Im trying to price it and was just curious. Thanks

I got a YFZ throttle for like $30

What i noticed about the FCR40 is how stiff the return spring is. Its a real thumb killer and i need a solution to make it soft like stock. I am a dune rider and spend many hours cruising the dunes- i dont want a twist throttle.

i purchased the carb from service honda (waiting for mail)

i'm buyin a Motion Pro twist throttle for the 2004 trx450r kit.

it should fit??? any modifications??

it might fit but the 450r doesnt use an FCR. But i think twist throttles are universal.

got my 40mm FCR

mods i have:

full yoshi titanium
ESR Air box eliminator kit

(hot cams later)

i'm going with 1-1/2 turns out
42 pilot
180 Main
Needle 2nd from bottom

does this sound correct?? at sea level??? i just dont wanna blow the engine up from being to lean.

thanks guys this post helped me big time!!!