Need help jetting my FCR carb?

[400exBro]

I just recently picked up a 03 CRF 450 40mm FCR carb with the noss adaptor, the guy before me had a full hmf system, with a hrc style air box lid.
I am currently running a full sparks pipe, sparks air filter kit, and a open air box lid. My jetting on the stock carb is a 190 main, sparks needle on the 3rd grove and a 50 pilot jet.
What do you recommend jetting the FCR carb to?

also any tips that you suggust i do, or anything i should watch out for when putting the carb on.? I have never jetted an fcr carb, i have heard they are difficult to get perfect.

thanks

[BSTURDIVANT]

We ran a 170 main and did fine with a full Sparks and HRC lid!

[chad502ex]

Originally posted by 400exBro
I just recently picked up a 03 CRF 450 40mm FCR carb with the noss adaptor, the guy before me had a full hmf system, with a hrc style air box lid.
I am currently running a full sparks pipe, sparks air filter kit, and a open air box lid. My jetting on the stock carb is a 190 main, sparks needle on the 3rd grove and a 50 pilot jet.
What do you recommend jetting the FCR carb to?

also any tips that you suggust i do, or anything i should watch out for when putting the carb on.? I have never jetted an fcr carb, i have heard they are difficult to get perfect.

thanks

id say for you about 175 or so, 48 pilot. The accel pump adjust is a bit tricky not getting the back of the slide wet.

here's a link on fcr boring
http://www.exriders.com/vbb/showthread.php?s=&threadid=164087&perpage=15&pagenumber=2


hope this helps

chad502ex.com

[400exBro]

what is the stock pilot on the crf carb?
I don't have it in front of me right now, it is suppose to be shipped some time this week.
Also do i need to use the CRF hot start cable? i have read elsewhere that the stock hot start cable will work as well?

Also what is a good clutch lever and hot start perch set up?

[chad502ex]

Originally posted by 400exBro
what is the stock pilot on the crf carb?
I don't have it in front of me right now, it is suppose to be shipped some time this week.
Also do i need to use the CRF hot start cable? i have read elsewhere that the stock hot start cable will work as well?

Also what is a good clutch lever and hot start perch set up?

I use the crf perch with hot start setup and crf hot start cable. the crf hot start cable is 90 degree bend into the carb and fits perfectly.

[R3Concepts]

We use a YFZ setup on the FCR carb, looks good with the little GTYR thumb lever HS also..The stock pilot is a 42 and wouldnt stray far from that, maybe a 45, depending on altitude. Like a 170-175 main is where are usually at with them. Middle clip on stock FCR needle.

[400exBro]

i am about 1000 feet above sea level.

Just to clarify, the stock TRX hot start cable will work as well?
I will get the crf cable when i decide to buy my lever and perch set up. i am tight on money cause i start University in September.

[400exBro]

Okay i put the FCR carb in with no real problems at all...
Start and idles nicely.
Do you think that a 185 is to rich? it seemed to pull fine on top with no back firing or the engine trying to die out.? I will ride it some more and make sure that is fine, i will then try a 170 and 175 just to make sure.

Another problem, how do i adjust the accel pump? i have a bogging problem when going from a low idle and just punching the throttle wide open? I almost think it may be getting to much fuel? ( that is what it feels like)
Also where abouts is the air fuel mixture screw located? there is a slight amout of poping on decel and would like to richen up the slow circuit.
thanks

[motox450]

Right now I am running a 180 main and a 50 pilot 2 turns out on the air screw. I think i may be a little rich on top, but I am still getting some popping on decel so i think I need to go another half turn out on my airscrew and if that doesn't work I am going to a 52 pilot. I am running a stage 2 hotcam, free HRC kit, and Dr D slip on. I have an 02crf carb so jetting may be a little different. Also I am at sea level. Hope this helps.

[400exBro]

Do you know how to adjust the timing on the Accel pump? i think my squirt time is to high.
Also where abouts the fuel mixture screw, about the same place as the stock carb?

I think a 175 main may do well for me then, 1000 feet above sea level.

thanks for the help.

[cals400ex]

the fuel screw is on the bottom of the carb, like on the stock carb.

[400exBro]

After riding the 450 for a while with the fcr at the setting i had mentioned above, it will pull really well there is no missing or back firing when i roll on the throttle to WOT, the 185 main seems to work well. (is there away to find out if the main jet is to rich?)

the only problem i am having is when going from a low idle to WOT fast it will die out on me or hesitate. I am sure this is the AP shooting to much fuel? into the engine at once. So how do i get rid of it. If i really have to i will take the carb back off, but is there away to fix it without having to go through all that hassle again??

other then that, this carb seems to improve the torque, or the acceleration of the quad, front end likes to come up a lot now, next will have to be a 13:1 piston and cam.

thanks for the help

[400exBro]

so no one knows how too?

[RobRacing]

You can't adjust the accelrator pump. You could try the boysen quickshot. The stock 450r carb had the same bogging issue you are talking about. Just learn to roll the throttle on and you shouldn't have any problems.

[R3Concepts]

Originally posted by RobRacing
You can't adjust the accelrator pump. You could try the boysen quickshot. The stock 450r carb had the same bogging issue you are talking about. Just learn to roll the throttle on and you shouldn't have any problems.

Holy old thread. On an FCR you CAN adjust the AP. Also the QuickShot is a big waste of money. It has more to do with the leak jet.

[400exBro]

ya old thread...

i have the problem fixed now, she runs strong.
only bogs a bit but i have a larger pilot jet coming.