Just got my 05 250 x back on Friday, had a hot cam stage 1 cam installed, replaced the stock piston with a wiseco high comp piston, also paid to have the valves replaced when he was in there, the intake valves showed signs of wear and leakage. Any way when I got the bike back it had all kinds of new low to mid power, but had a terrible off idle bog when the throttle was quickly twisted. So all weekend long I changed different settings and kept getting closer to no bog, finally tonight I made a few more adjustments and was able to finally tune out the bog with the fuel screw adjustments.

Well this is the final settings for a flat out ripping no hesitation at any speed machine    

PJ  40 (stocker)
MJ 165
LJ stock
Needle on 4th clip
fuel screw adj. to 2-1/4 turns out:

Altitude < 1000 , temps 85 and climbing

By the way I have done all the CCC mods, air box cut, pink wire snipped, R header and Pipe (50.00 ebay) , JD jet kit, hot cam, plus the high comp piston, My favorite mod so far is the Rekluse clutch.

The machine just jumps of the face of jumps and whatever now with just a slight blip of the throttle   

whats with all the different needle numbers? i have a nyc-u  told i need a nyc-q . i know its diameter and taper which affects main jet size.
is there a chart that shows dimemsions of ALL the needle jets?
thanks
steve

biggest jet i got from JD was the 162

My brothers 250x has developed a problem since his last time out it is bone stock.
The problem he has encountered is the bike will not idle when it does start it sputters and pops. I have checked the valve adjustment and that is with in specs and while I was into it I removed the carb for cleaning and a re jet. While I am into it should I be looking else where?

I live in the Washington D.C. area and ride in Virginia both in the western areas and the eastern areas. 200ft to 1500ft.   I own a 2006 250x.  The bike is shipped lean.  Here are the mods I have done:

Pink wire mod:  Raises the redline!
Opened the airbox per honda technical
Removed the rear portion of the baffle, cut and spot welded the screen in place. Only for woods riding!!!!

These are my jetting specs:
150 Main Jet
145 Leak jet
Screw 2 1/4 turns out


The bike runs crips and have had no problems.  Big difference over stock and is also quieter.  I ran the bike with no baffle and it ran great but was a little lound hence the baffle mod.   Also the bike starts way easier.   Hope this helps, Missle

I"ve got the CRF250X low end Bog.
I need some help, the Guys at Honda dealer in Reno Nevada (7000') don't know what to advise me. I ride at 6500' to 7500'
2006 Honda CRF250x / Ca. model, All stock, No mods yet! until I get it dialed in.
bought from dealer in Petaluma CA. (sea level). #40 pilot, #130 main.

I ride form 4,000 to 8,000 and my bike runs great! I bought it used with th JD kit but I would try it with the stock needle.

Red needle in the 4th clip, 155 main, 42 pilot, 2 turns and  leak jet # 55
Factory exhaust and air box opened.

The JD instructions  say 150 main for 7,000

6500' Total stock 06 CRF250x Calif smog model.
Major bogg. any good advise?
Brad in Lake Tahoe, CA.

2006 250X

CCC modded air box
removed (completly) sparky and diffuser

160 main
42 Pilot

thinking of switchin to a 155 main.

havnt touched needle clip or fuel screw

I have modified two '06 CRF250X's with great results using the air fuel ratio sensor on a DynoJet  dyno. The main goal was to improve power all over and keep it less than 94 dba and to carburate well from low to high.  After the modifications  both bikes pulled dead even with a '06 CRF250R until the middle of 6th gear. In the woods I love my X allot more than my 05 KTM 450 EXC (which is a great bike that weighs 265 lbs with gas)


Wisconsin and Michigan riding 650 feet above sea level 70 degrees 50% humidity

Here is my list and I believe you need to do it all to get the best results:

Muzzy Ti pipe with quiet insert and spark arrester
Air box mod (cut off top)
Twin Air billet cage air filter kit (very trick and eliminates the screen plus the filter is flame proof)
45 pilot jet
1.5 to 2 turns on Zip Ty fuel screw
Richen needle 1 groove down
155 main jet
Power now rear blade only
Boysen pump cover

Drill 7 holes 5/8 diameter holes across the top edge of the air box door (drill these from the inside of the door between the two ridges of plastic 1” center to center)

Now you can tune your bike to the altitude or conditions with a simple piece of duct tape. When its hot and humid leave all the holes open and lean out the fuel screw to 1.5 turns out. In nice weather (60-80 degrees 40-60% humidity cover 3 holes with tape and set fuel screw to 1.75 turns out.  When its cool out 40-60 degrees and low humidity cover more holes as needed and turn the fuel screw out to 2 turns.


I also installed a 51 tooth rear to smooth out the gear ratio’s a bit. And I installed a Recluse clutch (great product).

The bike is a blast to ride in the woods and you can ride much longer with less rest stops, because the bike is so light and smooth.

For Ice Racing  go to a 160 main jet and install Fredette tires and Moto Missile fenders and go have fun. Check out the web site below for more info on ice racing.

Joe Koenig  
www.dieseljo.com

"After the modifications both bikes pulled dead even with a '06 CRF250R until the middle of 6th gear"

i hope thats a big typo.

Hawaii-Rider said:

Where is the pink wire?
what does it do?

The Pink wire allows the bike to rev higher, removes the rev limiter for the most part. I personly wouldnt bother with removing it.

04 CRF250X, sea level, 90F, 49 state
Air box cut open, drilled air box under battery, Exhaust baffle drilled out
145 main
42 pilot
zip ty
Stock Needle clip down 5 from top, 2 more than stock
Air screw out 2 turns

Added a Pro Circuit muffler and Twin Air Kit, so I changed the jetting :
160 Main
42 pilot
Zip ty out 2 1/4 turns
55 leak Jet
Neddle recommended in the Closed Course Mod 4 down fron top

Added an 05 "R" cam, no change in jetting


Runs great

Runs great, front wheel comes up on a twist of throttle

Hey guys, i got a 06' CRF250X completely stock and have not done any adjustments.  Im getting the bog everyone is talking about and it is driving me up a wall.  I have no idea what im doing so anyone please help.  Im at 150'.  Thanks,

John

Kx65crazy said:

   my settings are on the bottom.i ride sea level to about 5000 ft no bog.
after jetting i had to fine tune the air screw.in the end i think thats all it was
the quick shot was probably unnescary. do a search for the AP mod i never did it cause i got rid of my bog before guys started talking about this mod.

I have a couple of questions. Is it the bigger the number of the main jet, the leaner it will be? If so, i see a lot of people with around a 150 main jet at about 1000 feet and are getting great improvements.  I'm at 150 feet, and the weather is around the mid 50's and getting colder. Should i go to a 140 instead or something? i dont have any mods to my CRF250X.  Also, can you buy individual jets, if so, were at?  I have already tried adjusting my pilot screw but im still getting a bog.  its at about 3 turns out and is running fine.  Thanks,
John

I am pretty sure the bigger the main jet the richer..
My 05' 250X came with a 140 stock main.. With my JD Jet kit I have upgraded to a 162 I think for winter I should be at a 165.
But I have also cut my airbox removed the air filter screen and removed the diffuser out of the exhaust.
What I havent done yet but am going to do soon is upgrade to a 42 pilot from a 40 and get a 55 leak jet..
also look into doing the AP Pump Mod... then your bog should be all gone..
If you dont want to modify your airbox There are other people on here with settings you can go off
Good luck
oh yeah im at the same elevation as you

The JD kit includes 5 main jet sizes; 150, 152, 155, 158, 162, and two needles (one for cold weather) The JD needles are a good mod as they are tapered slightly different than stock and therefore react a little differently. Do an airbox mod and airfilter and get ready to fly
05 CRF250X
42 pilot
162 main
(no need to change the leak)

How should I jet my 06 (california model) 250x?

I have the Dr.D exhaust, airbox mod, JD jet kit, leakjet kit, power surge, emissions block off and will be installing a hotcams stage 1 cam this week. I am between 1000-3000 ft in SoCal.

  Thanks, Jason