Jump to content
Sign in to follow this  

Please help, jetting a stock 250X

Recommended Posts

Hello, and right off the bat let me ask apologies if this information had been covered. I am one of the unlucky few who has dial-up internet, and search times are getting longer and longer! :cry:

I own a 2004 250X, live at sea level (about 1.5 hour drive from Atlantic City), and have a terrible bog off-idle. (It will downright stall out if I try to hit the throttle hard from a dead stop, and it also does this with the bike in neutral).

I am interested in the JD jetting kit, and would appreciate a nudge in the direction of the right jets to try starting out with. The carb and rest of the bike are still completely stock. I am not yet interested in cutting the airbox, or modifying the exhaust -- I'd like to do this in steps, first getting rid of the bogging problem with rejetting (if possible).

Can someone help this new-comer jetting for the first time?!

Also, will I need any jet wrenches? What size (6 or 8 mm) and what shape?

One last question: JD kits don't come with any leak jets it seems. Is this an important jet to change when rejetting?

Thank you very much, I appreciate this web site and your information.

I wanna get this thing ripping and roosting!!! :cry:


Southern New Jersey (lots of woods here).

Share this post

Link to post
Share on other sites

The first mod I did to my 2004 was the JD kit and I love it. I have only cut the top of the air box and followed the kit instructions and it worked great. I have since installed a 42 pilot and it helped even more on the bottom end. If you have a problem or question JD will answer you on the Jetting Forum.

Share this post

Link to post
Share on other sites

Would you recommend also changing the main jet? Or should I just change the pilot jet for now? :cry: How about the leak jet -- is that one that matters much?

I was thinking of going to the next size up on each jet, so long as I'd already have the carb apart. The leak jet, though, taking it up a size will mean "less" gas is applied to the intake from the accelerator pump... at least I think...

Is that right?

Thanks for your time,


Share this post

Link to post
Share on other sites

I have a CA bike and run at about 3,000 to 3,500 foot in elevation at about 50-70 degrees. Right now I am running a 155 main, 42 pilot, JD blue needle on the 4th position and 2 turns out on the fuel screw. Lower altitude and/or warmer calls for richer jetting, higher elevation and/or colder calls for leaner jetting. JD's kit has excellent recommenddations for all conditions.

Share this post

Link to post
Share on other sites

Does anyone have the instructions for moding the airbox and for rejetting instructions online for the crf250x

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

  • Similar Content

    • By Nicturner
      Hi fellow thumpers,
      firstly if there is other threads on this topic I apologize.
      i have a 2009 KTM 450 exc. I live at 5500 feet. I have a keihin carb. I currently have it set up with 
      green needle (jd kit) @ 4th from the top
      main #175 
      pilot #42
       in setting it up for some desert riding I plan on doing next month (LAB2V). Right  now I’m getting a bog if I rack the throttle a few times. I’m reading this is semi normal as the accelerator pump has a hard time refilling.
      i have put a new diaphragm, spring, lean jet is at #40 and air fuel acre 1 and 1/8 out.
      im planning on going back to 172 main, red needle 5th from the top and #45 pilot.
      i normally ride the trails around lake arrowhead and Big bear in California. The trails are single track from 5000-10000 feet.
      Anyone see any issues with either set up?
      how about the big if I get on it a few time ( not really noticeable when riding)
      sorry for the questions. This is my first carb I’ve ever worked on. 
      Thanks in advance 
    • By SNORE125
      Anyone else have 130 main and 38 pilot jets already in the carb I took the wifes ttr 230 carb apart to add the bigger jets and this bike from 05 that I bought new already had them in it? I was reading that they came with a 125 main and a 36 pilot.
    • By Charles Joseph Miron
      Hello all.  Need a helping hand here..  
      I bought an older TT225 and am not about to spend almost $600 on a new carburetor for it. So I'm hoping someone can help me out with an idea of what (other than original carburetor) style, type and brand I should go with..  I'm also having a bit of trouble finding info on this bike.  It's a 1986 Yamaha TT225.  
      Thank you in advanced
    • By Br0ck
      Hey guys, I went on vacation all summer and let my bike sit (2002 CR250). When I got back I ripped it apart and cleaned carburetor and put it back together and it started fine and ran alright, but idled really high. I adjusted the idle screw and realized it was a ridiculous amount of turns out. I can't remember exactly how many but id say 6+ turns out. My killswitch was a POS and didn't work anymore so I replaced it with an oem replacement. My last ride I crashed the bike pretty bad and I was off the bike for 2 weeks. I can't get the bike to start ever since I got installed the new killswitch. I think I wired it right I just replaced one wire at a time and it looked pretty straight forward. I verified it by testing spark while holding it in I was getting no spark but with it in running position it would spark. 
      Anyway I am just looking for some base settings for the Mikuni TMX to get my bike running again, my carburetor has a 35 Pilot and 380 Main jet which appear to be stock. I am located in Edmonton, AB, Canada which is about 2500ft and usually ride between 10-25 celcius.
      Thanks for any replies. 
    • By Goon Rides
      Hey guys... so I have a problem... I took the bike at Cal City, broke it in, and while I was doing so, the bike was bogging in first gear (Yes, first gear). Also it doesn't idle at all. I have to keep blipping it otherwise it'll stall. So I adjusted the screw circled in image 1. Well I was listening to the sound of the of the bike, yet the rpm's weren't increasing, and it was still stalling. So then, I unscrewed the screw in image 2, well I found out that it was fully twisted to the right. So then, I twisted it to the left, still nothing; it was still stalling... where's the idle screw? I am sure that the screw in image 1 is for the air/fuel mixture screw, and the screw in image 2 is the idle screw, just broken? I don't know, any and every help would be appreciated.