Jump to content
Sign in to follow this  

2009 klx250sf

Recommended Posts

I have a 2009 KLX250SF. I live at about 350ft ASL. Snorkel off, Big Gun Evo R exhaust slip-on.I have a 17.5 pilot jet, 130 main, and the stock needle jet and jet needle. Jet needle is all the way to clip 5(lowest clip.) Went for a run today it was about 65 degrees and it stalled along the way. Started back up after about 10 minutes. Took off the tank and checked the sparkplug. White/Grey. Couple dark spots that looked like speckles. I checked the rubber boots and they look to be tight. Am I missing something?

I forgot to add that the carb isn't a CVK34 anymore, it is a TM-36-68 A/P. The main jet came stock at 130, but the idle would drop very slowly when I gave it throttle and my friend owns some Harley's and had a left over 17.5 Mikuni pilot jet that he let me use, it was a 12.5. I thought it was lean because when I went for a ride it felt like it was hauling ass. Lifted the front wheel off the ground a from first to second gear.

Share this post


Link to post
Share on other sites

Do you know how to tune a carb? For instance, have you read any information on carb tuning - either generically or specific to that carb?

This is pretty generic info: http://jetsrus.com/FAQs/FAQ_rejetting_101_how_to_rejet.htm

Why is your needle on the highest position? More does not always mean better.

I'm also curious what made you choose that carb - TM 36mm. I could be wrong but it seems like it may be a bit big for a 250. For instance the race ready KTMs 450s come with a 39mm FCR. I would think a 33 or maybe a 35mm would be a better match.

Share this post


Link to post
Share on other sites

This is my first bike I ever started working on myself. I've read some articles about carb tuning on the internet like the HS40 manual.

I put it on the the 5th clip because it seems to run lean. When I look at my spark plug it's a whitish gray which I hear it should be a chocolate color. It idle's very consistent which makes me believe I don't have an air leak in my intake.

I chose a tm36 because next season I plan to get a 351 kit. I thought the bigger the carb the more air. So just put bigger jets in to match.

Is it as simple as this carb is just to large for a 250cc?

Share this post


Link to post
Share on other sites

No, you can jet it to run ok I'm sure.

Read the FAQ in that link.

Identify what jets you have now.

Buy a fuel mixture screw that you can adjust when the bike is running.

Start with the idle, the idle should start to miss when you are less than 1/2 turn out on the screw. If it does, that jet is good. Back the screw out to a turn or a turn and a half.

Next to the main jet. The easiest way it to go bigger until you notice the bike starts to bog down under full throttle. Then go back down one size and it should run well, but still be a touch rich if not perfect.

Share this post


Link to post
Share on other sites

Hey man I just bought a 250sf, how much if anything did you gain from the exhaust upgrade?

Share this post


Link to post
Share on other sites

I just opened the airbox up and Richened the fuel mixture, no exhaust mods as of yet. This alone made a dramatic difference. From never wanting to start and no snap in the throttle, to pulling quite well out of the hole. I would think an exhaust on this bike would be a dramatic difference over the airbox mod and jetting. I can just fit my pinky finger in the pipe!!!

Get that exhaust!!

Share this post


Link to post
Share on other sites

the exhaust was worth every penny to me. feel of the rumble when i twist the throttle, psychologically makes you think its a new bike. physical realm goes, yes there is quicker response. if i had to go back to the old pipe i would dread it.

Share this post


Link to post
Share on other sites

I have played with the jetting on the stock carb and still get a white-ish color on plug. I would not measure the jetting on the plug alone. Ride the bike and you will feel and hear jetting issues. Surges, coughs and knocks all are jetting problems. My bike always idled great even when it was 3 jets out. Now the bike is jetted correctly and if you pulled the plug, it would be white-ish to grey depending on fuel.

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 Out for a rip are ya bud?
      I have a "new" KLX 140 for sale 
      I say new because it has less than 2 hours on it. 
      I bought this bike new in Brandon for my wife, she is not interested. 
      This bike is the small wheel version, low seat height, electric start. 
      Great beginner bike !
    • By Out for a rip are ya bud?
      I have a "new" KLX 140 for sale 
      I say new because it has less than 2 hours on it. 
      I bought this bike new in Brandon for my wife, she is not interested. 
      This bike is the small wheel version, low seat height, electric start. 
      Great beginner bike !
    • By Southwest ORV
      Hello friends, 
      I have seen some discussion about DRZ400 (DRZ400S, etc) vs whatever other bike, when it comes to power. My riding buddy and I threw down some good old drag races this morning on the way back home after some adventure in the forest. I own/ride a 2002 KLX300R. We ran two heats, one on gravel, then one one asphalt. Who do you think won? See below:
       
       
    • By Southwest ORV
      Hello friends, 
      I recently put a new Kenda Trakmaster II rear tire on my KLX300R. I'm loving the improved grip and overall performance. Here's a little video I put together of the tire in action...
       
    • By Southwest ORV
      Hello friends, 
      Just thought I'd share a short summary video of a 154-mile adventure ride my buddy and I did last week. Northeastern AZ has an unbelievable amount of rural trail/road to explore. My KLX300R averaged 71.5 MPG on this ride. 
       
×