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Fuel/air screw irregularities

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So all was well with my wr250f, and i got the JD fuel air screw for easy access, and also because their jetting kit was awesome. I was all dialed in as bike was great. Well today I put it in, and also dropped the needle a clip (now on 3 instead of 4) cause I was pretty rich when I checked the plug the night before, and I couldn't set the screw per the regular procedure. When I seated it all of the way, idle never changed. If I backed it out to around 3, idle went up. Went back to the 2t for standard setting, set the idle to a regular "earshot level" and rode . Bike was great. Mid and top end was great, and low was nice too. I did notice some irregular idling, and also revs being a bit too high for too long after pulling in the clutch without throttle applied. I went back to the old clip position, and same deal. Did I mess things up when I was playing with the idle screw? Cause I did mess a lot with the idle screw. I notice that I have more slop in the throttle before it engages as well. I'm kinda confused on this one. But something tells me it's a combo of idle screw and new fuel air screw setting. Or maybe I got some crap in the carb while swapping needles. Have made a lot if needle changes, and never had this happen. For info, it's a 185mj with YZ exhaust, all free mods, 71f, sea level. The power was great, things just felt a bit "off" with the idling circuit. Or coming down to the idle from high revs.

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You didn't say what year.  I have 04 and 05 and have done jetting changes as well.

 

I would guess your main jet is too rich and I would go back to the 180. 

When you change the main, it can have affects to the pilot circuit as well, just my experience there.

Only other thing could be the o-ring on the fuel screw... they will crack and not seal properly.

 

I was having issues with the 05 bike, and I dropped the needle and cleaned up throttle response and idle.

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My thoughts were exactly the same as yours. But it just doesn't make sense why would the stock fuel or screw everything's fine but the JD fuel air screw I need to change my main jet. The screw side-by-side look identical.

I plan on trying out the 180 main tonight. And also swapping back the Stocks screw and see what the results are. But something else seems off.

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Try backing off the idle screw a bit sounds like you have lifted the slide away from where it should be which is why the fuel screw is having little effect. I've had this before if I set the idle before the bike was warm enough. Idle hangs in gear just a bit too long then settles.

 

MM 

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Hey Marty, not to hijack this thread so I'll stay on topic here.  That's the first time I've seen someone link throttle slide height to hanging idle, but I think its valid. 

 

And Lima, I agree with your comments as well, but I think you may have jumped too far in your adjustments.  Only 1 change at a time is best policy to stick to.

 

JD makes specific recommendations in their documentation and seems to have done their homework pretty well.  My first and second JD kit setups were per their documentation and I didn't have to adjust anything but fuel screw and idle. 

 

Then I tried the Dynojet kit and was disappointed... lesson learned.  I may back-track and get the JD kit just to clear up frustration factor.

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