2009 KLX250SF Carb Tuning Advice
#11
"Never remove the airbox lid until/unless the CVK is running a Lidless setup. Never run a lidless setup until a performance slipon or full performance system is installed."
This makes sense, this is what I was confused about at first, I thought it would work to run lidless with the stock exhaust as long as I had a bigger main jet and used the DJ needle.
"If your carb is faulty, or valves too tight, or spark plug bad, etc etc, doing performance setups is counterproductive."
Yeah, I totally agree, I havent been able to find anything obvious wrong though, the splark plug looks good and the spark is strong, I didnt see anything wrong with the carb when I took it apart, the float level is correct, I adjusted the mixture screw using the 'halfway between 2 idles drops method", put in a new air filter and changed the oil.
"You say you rebuilt the carb, so how bout a test.."
I appreciate the test, I consider myself a lifelong student:
1) The holes in the emulsion tube were all clear, I didnt stick anything in them because I didn't want to damage them, but I was able to look through each one using a small flashlight.
2) I didnt lose the needle jet, but I did forget to put it in the first time I reinstalled the emulsion tube, but I noticed it when I wondered why the emulsion tube screwed in further than before.
3) The needle jet has a shoulder in it about 2/3 of the way down it's length, the should should be closer to the bottom side than the top side when it's installed correctly. The needle jet also has one end slightly rounded, that is the end that should butt up against the emulsion tube.
4) The first time I tried to put the cap on the end of the spring when around two of the tangs, but inside the third tang (if that makes sense) so it was not completely centered, I redid it though to get all 3 tangs inside of the spring so it is completely centered.
5) The diaphragm seemed to be very slightly smaller than the groove, but working it into the groove all around was enough to keep it in place as I put the cap on. I didnt use the trick of keeping it in warm water, but it was definitely completely in the groove when I got the cap on. I was able to circumferential seat the cap against the top face of the carb body with only light finger pressure, there were no gaps between the cap and the carb body top face.
Does any of that seem wrong? I'm pretty sure I did the teardown/rebuild correctly. I will try with the "Airbox lid w/o snorkel, DJ124 main, DJ needle on 3rd notch with 2 extra washers above it, DJ Spring, Stock slide (not drilled)" and report back.
One other comment though, the current setup that I have does make significantly more torque at the low/mid compared to how the bike was originally, so if it is wrong there is still something working about it.
Thanks!
This makes sense, this is what I was confused about at first, I thought it would work to run lidless with the stock exhaust as long as I had a bigger main jet and used the DJ needle.
"If your carb is faulty, or valves too tight, or spark plug bad, etc etc, doing performance setups is counterproductive."
Yeah, I totally agree, I havent been able to find anything obvious wrong though, the splark plug looks good and the spark is strong, I didnt see anything wrong with the carb when I took it apart, the float level is correct, I adjusted the mixture screw using the 'halfway between 2 idles drops method", put in a new air filter and changed the oil.
"You say you rebuilt the carb, so how bout a test.."
I appreciate the test, I consider myself a lifelong student:
1) The holes in the emulsion tube were all clear, I didnt stick anything in them because I didn't want to damage them, but I was able to look through each one using a small flashlight.
2) I didnt lose the needle jet, but I did forget to put it in the first time I reinstalled the emulsion tube, but I noticed it when I wondered why the emulsion tube screwed in further than before.
3) The needle jet has a shoulder in it about 2/3 of the way down it's length, the should should be closer to the bottom side than the top side when it's installed correctly. The needle jet also has one end slightly rounded, that is the end that should butt up against the emulsion tube.
4) The first time I tried to put the cap on the end of the spring when around two of the tangs, but inside the third tang (if that makes sense) so it was not completely centered, I redid it though to get all 3 tangs inside of the spring so it is completely centered.
5) The diaphragm seemed to be very slightly smaller than the groove, but working it into the groove all around was enough to keep it in place as I put the cap on. I didnt use the trick of keeping it in warm water, but it was definitely completely in the groove when I got the cap on. I was able to circumferential seat the cap against the top face of the carb body with only light finger pressure, there were no gaps between the cap and the carb body top face.
Does any of that seem wrong? I'm pretty sure I did the teardown/rebuild correctly. I will try with the "Airbox lid w/o snorkel, DJ124 main, DJ needle on 3rd notch with 2 extra washers above it, DJ Spring, Stock slide (not drilled)" and report back.
One other comment though, the current setup that I have does make significantly more torque at the low/mid compared to how the bike was originally, so if it is wrong there is still something working about it.
Thanks!
Last edited by johncconsiglio; 04-28-2021 at 07:58 PM.
#12
Wow.. You're good !
So there should be an even smooth power delivery when holding WOT from 4k rpm, in 3rd gear .. Over-rev starts at about 8000 rpm ( with stock exhaust) - so power will wane from there on up to 10,500 rpm. No sputtering, roughness, or any other such issues are normal ops. Such things indicate a problem.
So there should be an even smooth power delivery when holding WOT from 4k rpm, in 3rd gear .. Over-rev starts at about 8000 rpm ( with stock exhaust) - so power will wane from there on up to 10,500 rpm. No sputtering, roughness, or any other such issues are normal ops. Such things indicate a problem.
Last edited by Klxster; 04-28-2021 at 05:47 PM.
#13
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