[Dezchik111]

Hi All, Just bought the 07 250x. I am planning on opening up the airbox, and removing the exhaust baffle. Anyone have any suggestions on what jetting to use. Must admit I'm not too jetting savvy and mostly rely on others expertise in this field. I changed the needle and main jet on my 04 and it seemed to make a huge difference. I know the 07's are quite a bit different than the 04's as far as porting and such. I typically ride between 2,000 and 8,000 feet elevation. Also has any one eliminated all the emissions junk on their 07. I have heard rumors of plug up kits that may be available. If so any advise on this issue???

[Halen]

My advise to you is this... check out the previous posts from the hundreds of fellow riders in the 'jetting' section as well as the CCC mods. Tonnes of great information from some very reliable people.
later... Van

[crf~rob]

i went 162main 42pilot on my 06. I also opened my airbox and installed the twinair filter...she runs like a champ!

[ibiro]

Hey Guys

Read Dezchik111 post before you answer. 07 IS different from the rest of them. Valid question Dezchik.

[crf~rob]

Thx Ibiro
I did, thats why I posted that my ride is an 06. I'm just offering up what worked for me , but honestly I'm not sure what the differences are between the 06 and 07 models.

[Dezchik111]

I checked the jetting forum before posting and didn't find any info on the '07 model. I havn't opened up the airbox yet, but on the first ride it seems to really want to backfire everytime I let of the gas. I don't know if that has anything to do with all the emissions BS that comes stock on the new bikes or not, but I'm guessing it could be part of the problem. Still looking for the so called "plug up kits" I have heard rumor of.

[Asmith]

The 07 has very little differences over the 06 on the 250X.

The stock jetting is:

NLBU #2, 132 mj, 42 pj, 55 leak, 2 1/4 fs

We ride similar elevations 1500'-4000' regularly and up to 8000+ on occasion.

Do the CCC mods.

1) cut the airbox
2) remove back fire screen and stock air filter.
3) install Twin Air Powerflow flame retandant filter.
4) install CRF's Only fuel screw.
5) install JD jetting kit set up as recommended ( red needle 5th clip, 158 Main jet ).
6) do the AP mod with the O-ring.
7) install White bros or Applied smog block off kit OR do the JB weld trick and leave the AIS in place (for the Rangers).
8 ) remove baffle from exhaust, cut discs off, drill 1/2" hole and reinstall.

adjust the fuel screw out 1 3/4 to 2 1/4 to eliminate decel pop

[ibiro]

My 2007 250X is made for the European market. No emission control junk fitted. The head is not even drilled for the emission fittings... lucky me.
Stock as follows:
Carb id: FCR14A
Main #132
Jet needle NKKT
Clip pos #3rd from top
Fuel screw 1 7/8 turns out
Pilot #42.

What amazes me is that with this stock setup, the beast STILL runs RICH after the baffle was drilled to 11/16". Not one pop ever on deceleration.

This is what makes me think there is a huge difference in the 2007 carb to the rest of them.

See this link
www.rickramsey.net/CRF250Xjetting.htm#carb07

Thanks for the input guys. We all learn