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Just got my JD jet kit!

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Well I just got my JD jet kit for my 07 250sx-f and I will be installing it tonight and testing it this weekend. I am very excited to see the difference it makes.

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I don't know about the 250, but my 450 is like a new bike after the JD kit. Way more bottom end power, and instant throttle response! It ate rear tires before, but its only going to be worse now. Can't wait for the update.

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Just got done installing my JD jet kit and it was very easy with the instructions that came with it. There was no guess work at all on what to do or which jets and needle to use. The directions even came with pictures and a leak jet and O-rings for the O-ring mod. I have never even taken a carb off before and I didn't have any difficulty. It is about 50 degrees here right now and I started it up in my basement and it sounded perfect right away with the recommended fuel screw setting. I have NO bog at all when cracking the throttle wide open really fast. I will post more info when I actually take it out to ride this weekend but for right now I'm very happy with the results.

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Just got done installing my JD jet kit and it was very easy with the instructions that came with it. There was no guess work at all on what to do or which jets and needle to use. The directions even came with pictures and a leak jet and O-rings for the O-ring mod. I have never even taken a carb off before and I didn't have any difficulty. It is about 50 degrees here right now and I started it up in my basement and it sounded perfect right away with the recommended fuel screw setting. I have NO bog at all when cracking the throttle wide open really fast. I will post more info when I actually take it out to ride this weekend but for right now I'm very happy with the results.

Your house must have been rumbling!

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Well I took my bike out today for about 2 hours but it was like 45 degress here. I have my bike jetted for 70 degrees plus for summer. When I first tried to start it, it didn't want to start unless I used the hot start. When it finally did start it had a pretty bad hesitation on bottom end then picked up pretty good. I think that its running like that because it is so cold. What do you think? I am running the 185 main jet, stock pilot, #60 leak jet, o-ring mod, and the red needle on 4th clip.

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use the Blue needle....low alt and 50 degrees with some overage in temps.

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Well I took my bike out today for about 2 hours but it was like 45 degress here. I have my bike jetted for 70 degrees plus for summer.

Cold air makes it lean particularly if you're jetted for warmer air temps. Re-jet for 45* and try again.

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The only thing the directions in the kit says to change for below 70 degrees is to move to the 5th clip

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the blue needle have the same straight diameter as the oem needle . the red one is step thikker ,so leaner . the blue is 2,73 mm the red is 2.74 mm

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Well I took my bike out today for about 2 hours but it was like 45 degress here. I have my bike jetted for 70 degrees plus for summer. When I first tried to start it, it didn't want to start unless I used the hot start. When it finally did start it had a pretty bad hesitation on bottom end then picked up pretty good. I think that its running like that because it is so cold. What do you think? I am running the 185 main jet, stock pilot, #60 leak jet, o-ring mod, and the red needle on 4th clip.

The stock main on that bike is a 175, are you really running a 185?

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Yes I am running a 185 because that is what jd recommended for 70 degrees and above. I don't really want to change the needle because I'm bot really going to ride it again until it gets warmer because I almost froze my nuts off in the 45 degree weather. So I may just leave it as is and test it when it gets to be 70

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You're not going to notice *too* much of a difference in performance between 45 and 70 degree weather. I don't change my jetting for those temps - the only change is my fuel screw which needs some major adjustment.

Have you properly adjusted your fuel screw?

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Cold air makes it lean particularly if you're jetted for warmer air temps. Re-jet for 45* and try again.

If he needs the hot start just to get it started (when engine is cold) its likely that his idle circuit is overly rich. At higher temperatures with less dense air, that's only going to be richer.

Go with JDs recommendations as a baseline I don't know about the 250s, but for the 450s the baseline works for low elevations at all temps up to 95 degree weather - only in extreme heat does JD recommend the red needle (leaner).

Try adjusting your fuel screw. If you're still baffled, call JamesDean for support. From what I hear he's very helpful.

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