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Just jetted crf250x, questions on fine tuning...

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I have an 07 crf250x

It had 130main and 42pilot

I went to a 152main, 45pilot and a Moose air/fuel screw 1/2 turn out.

Airbox, baffle and pink wire mods were done.

Temp is 40-60

Altitude is 800'-1050'

Light humidity, ATL Ga

Woods riding only:ride:

The bike rips mid-top now (I'm really surprised) but off idle just below mid it seems to be a bit weak, doesn't snap as hard as mid-top, something just doesn't seem to be hitting right:bonk: its a mild bog I guess you could say.

My question is, is this my pilot, my air-screw, or a combo of both? Which do you think is off and what needs to be done? When I adjust the air/fuel screw, I'm having to adjust my idle in and out to smooth it out, is this normal? Should I try the 42pilot? I jujst want the snap off idle like the mid-top is:foul:

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I have an 07 crf250x

It had 130main and 42pilot

I went to a 152main, 45pilot and a Moose air/fuel screw 1/2 turn out.

Airbox, baffle and pink wire mods were done.

Temp is 40-60

Altitude is 800'-1050'

Light humidity, ATL Ga

Woods riding only:ride:

The bike rips mid-top now (I'm really surprised) but off idle just below mid it seems to be a bit weak, doesn't snap as hard as mid-top, something just doesn't seem to be hitting right:bonk: its a mild bog I guess you could say.

My question is, is this my pilot, my air-screw, or a combo of both? Which do you think is off and what needs to be done? When I adjust the air/fuel screw, I'm having to adjust my idle in and out to smooth it out, is this normal? Should I try the 42pilot? I jujst want the snap off idle like the mid-top is:foul:

Here's the rule: fuel screw is to be at 1.5 turns out, defined by the pilot jet size. If your is only 1/2 turn out, it's too big. 42 is fine for the 250x.

However, the stock needle sucks. Get a NCVS (off the R model) on the 4th clip, and your transitional issues will go away.

Next is the leak jet, You MUST change the leak jet to a 50 and adjust the accelerator pump linkage if you want snappy throttle response. Can't ignore this, even though it's a pain in the but to tune (you have to remove the shock).

The off-idle snap is all about the accelerator pump tuning. You want to see the fuel squirt out of the apump nozzle, right past the carb and into the head. It has to do this without the stream of gas hitting the slide. If it does hit the slide, you turn in the linkage adjustment 1/2 turn clockwise at a time until it just misses the slide.

You will be amazed at the difference

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tune the fuel screw with the bike hot and idle set low, turn the screw in till it coughs (lean misfire) or dies, then back it out 1.25 to 1.5 turns from there. your in the ballpark.

stk 55 leak is fine IMO, hard pressed to tell the difference in a 50. DO NOT put a 70 in it per the ccc mods.

evaluate the run quality warmed up and riding not twisting the grip on a stand

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Here's the rule: fuel screw is to be at 1.5 turns out, defined by the pilot jet size. If your is only 1/2 turn out, it's too big. 42 is fine for the 250x.

However, the stock needle sucks. Get a NCVS (off the R model) on the 4th clip, and your transitional issues will go away.

Next is the leak jet, You MUST change the leak jet to a 50 and adjust the accelerator pump linkage if you want snappy throttle response. Can't ignore this, even though it's a pain in the but to tune (you have to remove the shock).

The off-idle snap is all about the accelerator pump tuning. You want to see the fuel squirt out of the apump nozzle, right past the carb and into the head. It has to do this without the stream of gas hitting the slide. If it does hit the slide, you turn in the linkage adjustment 1/2 turn clockwise at a time until it just misses the slide.

You will be amazed at the difference

How do I do the linkage adjustment and how am I supposed to see the ap nozzle squirting? I'm very new to these 4stroke carbs and I've only had this 250x 3 weeks and it seems to be all about the jetting with these x's!

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tune the fuel screw with the bike hot and idle set low, turn the screw in till it coughs (lean misfire) or dies, then back it out 1.25 to 1.5 turns from there. your in the ballpark.

stk 55 leak is fine IMO, hard pressed to tell the difference in a 50. DO NOT put a 70 in it per the ccc mods.

evaluate the run quality warmed up and riding not twisting the grip on a stand

Thanks, I will try that. Everyones swore by the 42p except my tuner, thats why I have it. I had a 42 in it, but a 130main, terrible...:bonk:

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How do I do the linkage adjustment and how am I supposed to see the ap nozzle squirting?

THE LINKAGE SCREW IS ON THE RIGHT SIDE OF THE CARB, UNDER THE BLACK COVER (THOTTLE CABLE WHEEL COVER). YOU WATCH THE SQUIRT BY LIFTING UP THE SUBFRAME AND WATCHING THROUGH THE BACK SIDE OF THE CARB.

I'm very new to these 4stroke carbs and I've only had this 250x 3 weeks and it seems to be all about the jetting with these x's!

:bonk:

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Should be fine, hasn't been touched. Its geared kinda high (14t/53t) so I'm thinking that may be why it feels like its almost got a bit of bog to it.. Feels like it takes a sec to really get going, like I'm rolling the throttle on. Mon I'll be putting the 13t/51t gearing and I think that will tighten up the problem. Well see, otherwise I will break down and get a JD Kit...:bonk:

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Be carful not to change to many things at once. Make adjustments to one circuit at a time and test. You may find that the problem goes away by doing the simple stuff first.

Happy Tuning.

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more leak jet question, my crfx 250 after cleaning the float bowl and jets. my gas mileage has been cut in half. could i have changed the adjustment of the accelerator pump and would the that change the gas mileage? the leak jet is shooting a lot of gas when on the bench with gas flowing to it it shoots a strong foot out of the cab. is there also a change from that D type adjustment screw on the X. any bacis place to start these adjustments? thanks

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more leak jet question, my crfx 250 after cleaning the float bowl and jets. my gas mileage has been cut in half. could i have changed the adjustment of the accelerator pump and would the that change the gas mileage? the leak jet is shooting a lot of gas when on the bench with gas flowing to it it shoots a strong foot out of the cab. is there also a change from that D type adjustment screw on the X. any bacis place to start these adjustments? thanks

Re jetting your bike to the correct jetting will cut you down to 25-35 mpg.

Apump stream should be about 1-2' long stream, and never hit the slide.

The 'D' screw? You mean the fuel screw, or the apump linkage screw? The latter has to be modified, but you don't need to adjust it but once every couple of years.

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