Jetting for 416ex, FCR CARB

[HingeDisc07]

Hello I need some help with jetting my 39 fcr carb. Heres the specs:

Elevation 840 ft.
Mods: je piston 416, stage 2 hotcams, hmf muffler, fmf powerbomb header, lid off.

Whats a good spot to start? thanks

[underpowered]

i would start at about a 50-52 pilot, and a 175 main.


i have a 41mm on my 426 and run a 55 pilot and a 180 main on it.

[HingeDisc07]

Im sorry this is probably a stupid question but, does the fcr carb have a fuel screw and a needle? thanks

[underpowered]

yeah, the fuel screw is kinds up in a cave on the back of the bowl. if you look, many people sell a longer mixture screw for the FCR carb because it is a pain to get to on the bike.

and the needle is under the top cap of the carb, take out the three screws on teh top of the carb and the needle is under there.

[HingeDisc07]

Whats a good spot to start with the needle and fuel screw? thanks

[underpowered]

on mine the needle is a stock YFZ needle, on the very bottom clip. the fuel screw is about 2 1/2 turns out.

[HingeDisc07]

Is there any difference between yfz needle and a fcr needle?

[underpowered]

idk if there is any difference or not. i got the carb used and when i took it apart to clean it i had the stock needle laying around and put it in. it was the same as teh needle that came out of the carb other than it was aluminum instead of brass, but idk if the other needle was stock either.

[HingeDisc07]

hey underpowered, thanks for all your help! Going to mess with jetting tommorow.

[underpowered]

no problem, i try to help where i can

[HingeDisc07]

I need some more help here:

When I try to install the 52 pilot screw into the carb, it doesnt want to screw in. Is it the one located to the right of the main? thanks

[HingeDisc07]

Heres the pic:

[Ginxd00]

STOP, STOP, STOP, DO NOT use that pilot your trying to use. FCR carbs use specific pilot jets. DRZ pilots will work. Call Carb Part or Sudco to get the right pilot jet. If you try to use the one you have you may damage the threads in the carb and then your SOL.

[HingeDisc07]

Hopefully I ordered the right jets from this web site.

http://www.jetsrus.com/main_page.htm

KEIHIN
SLOW JET N424-25

[Ginxd00]

Originally posted by HingeDisc07
Hopefully I ordered the right jets from this web site.

http://www.jetsrus.com/main_page.htm

KEIHIN
SLOW JET N424-25

Thats the one, I would if it were me order a 50,52, and 55 just to be safe. I am using a 55 in the colder months and 52 in the warmer. I dont like running my fuel screw out more than 2 turns. I had it vibrate out on me before.

[HingeDisc07]

thanks alot. I just ordered a 50 and 52 pilot jet. Whats your needle set at right now? and will this fuel screw work?:

[Ginxd00]

Depends on you bike. remove your needle and check the letters on the top it should be either a OCEM-R or OCEM-P I run the OCEM-P on the 3rd groove from the top. The OCEM-R is a leaner needle than the OCEM-P. The fuel screw you pictured is what I am using. I try to keep my settings between 1 1/4 to 2 turns out.

[awsomeaussies]

I have a fcr with my 416 too. Should I also get the 50, 52, and 55? I ride between sealevel - 800ft.

[awsomeaussies]

Originally posted by HingeDisc07
thanks alot. I just ordered a 50 and 52 pilot jet. Whats your needle set at right now? and will this fuel screw work?:

What site did you find that fuel screw?

[HingeDisc07]

I got it off ebay. Got it pretty fast to.

[awsomeaussies]

Originally posted by HingeDisc07
I got it off ebay. Got it pretty fast to.

Sweet! Thanks:)