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jrafter
12-24-2006, 05:23 PM
After a lot of trial and error i have finshed the jetting on are 250ex.Ive worked on it off and on for the last couple of months not really knowing what i was doing.So i read eveything i could and went back and started from the beginning.

Let me start by stating some of the misstakes i made when i first started.

I add a K&N air filter hoping to get a little more throttle respond like i did with my 400ex...a 250ex carb is not the same as the one on the 400...my first misstake.

after adding the K&N i bumped up the main jet from a 95 to 97.5 keihin jets. i had done this on my 400 and i worked great...... no real change and it was now bogging down mid throttle.

tryed to adjust the fuel screw.....didnt have the right tool so i pulled the carb and adjusted it off the bike 2 1/2 turns put it back together.......still bogging down.

at first i thought i might be hitting the rev limiter but that wasnt it.then i just started changing jetts going bigger,smaller with out really knowing what i was doing or with out any thought as to how i was riding.

first off it almost never see full throttle so changing the main wouldnt have any effect...... since it came with a 42 pilot i thought that was just right because thats what i had to put in the 400....like i said the 250 carb is not like the 400.

i ended up with a 50 pilot jet and i started to see a good respond.I also got a fuel screw from and 04 250ex that i could adjust when it was runing with out any problems and that seemed to help.

IT was running real good but i still had some bogging at mid throttle than i went back to the how-tos on rejetting and there it was......i needed to rays the idle when adjusting my fuel screw get that set and than lower it again.

i ended up with a

50 pilot
needle is stock
97.5 main
fuel screw is 2 /12 turns
K&N

There was a big learning curve for me but it was worth it.
Hope this helps someone else.I know adding just an airfilter isnt much but i have to say on both the 250 and 400 airfilter and the right jetting have add a lot of pep.

also if i had thought about it could have pulled out my fuel screw and cut a grove in it but i went to the dealer and they ordered one for an 04.....getting that set was the bigest pain in the *****

ryanh250ex
12-26-2006, 11:08 PM
50 pilot is HUGE. I'm running full exhaust, UNI, no airbox/snorkel/choke and i'm still on the original 38 pilot. I am however having some light off-idle stumbling, so i will have to up it some, but 50 seems to be excessive unless you live at sea level (i am at 150 ft elevation) and it is extremely cold.

jrafter
12-27-2006, 06:03 AM
you might might be right.....yesturday was the first time i had a chance to ride it all day out on a lot of trails.

it was running rich.......but it ran great.

im still in the learning curve.....im going to try a 45 and see how that works.

I should have added that im 99% done working on it....but

ryanh250ex
12-27-2006, 07:17 PM
Originally posted by jrafter
you might might be right.....yesturday was the first time i had a chance to ride it all day out on a lot of trails.

it was running rich.......but it ran great.

im still in the learning curve.....im going to try a 45 and see how that works.

I should have added that im 99% done working on it....but

try this:

42 or 45 pilot
e-clip one notch below factory
fuel screw turned out some.

jrafter
12-28-2006, 03:21 AM
im going to dont just today......i finally collected all the jets that i needed.

jrafter
12-28-2006, 04:06 PM
Originally posted by ryanh250ex
try this:

42 or 45 pilot
e-clip one notch below factory
fuel screw turned out some.

i kinda feel dump posting how i rejetting and and everything was great and here im am still adjusting.

i took your advice and went back to a 45 pilot.

than it seemed to be running lean but i did see water in the air box that seem to of come in throught rubber boot for the snorkel.

air leak ...so i sealed up the boots for both the snorkel and the carb and the ideal drop off adjusted fuel srcew and it seem to run a lot better offer the whole throttle range.

ryanh250ex
12-28-2006, 04:20 PM
Originally posted by jrafter
i kinda feel dump posting how i rejetting and and everything was great and here im am still adjusting.

i took your advice and went back to a 45 pilot.

than it seemed to be running lean but i did see water in the air box that seem to of come in throught rubber boot for the snorkel.

air leak ...so i sealed up the boots for both the snorkel and the carb and the ideal drop off adjusted fuel srcew and it seem to run a lot better offer the whole throttle range.

air leaks are common if you are fiddling around with jetting i.e. removing/reinstalling the carb constantly.

i'd drop the e-clip one notch if you find that your quad is cutting out when you are at low rpms and crack the throttle.

jrafter
12-28-2006, 07:17 PM
Originally posted by ryanh250ex
air leaks are common if you are fiddling around with jetting i.e. removing/reinstalling the carb constantly.

i'd drop the e-clip one notch if you find that your quad is cutting out when you are at low rpms and crack the throttle.

Changing the needle is the only thing i havent done......im not sure how to take it about......

ryanh250ex
12-29-2006, 09:13 PM
Originally posted by jrafter
Changing the needle is the only thing i havent done......im not sure how to take it about......

pretty simple stuff.

1) remove throttle cable from top of carb

compress spring (kind of hard) so you can push the slide (cylinder-shaped shaft) upwards so you can remove the throttle cable from the slide

from there i think you pull the plastic collar holding the jet needle in place

you want to move the e-clip (it's shaped like an e and is attached to the jet needle hence the name) lower onto the needle.

removing and reinstalling that stupid collar is the biggest PITA ever, ask me how i know....

hope i've helped
-Ryan

jrafter
12-30-2006, 06:09 PM
Originally posted by ryanh250ex
pretty simple stuff.

1) remove throttle cable from top of carb

compress spring (kind of hard) so you can push the slide (cylinder-shaped shaft) upwards so you can remove the throttle cable from the slide

from there i think you pull the plastic collar holding the jet needle in place

you want to move the e-clip (it's shaped like an e and is attached to the jet needle hence the name) lower onto the needle.

removing and reinstalling that stupid collar is the biggest PITA ever, ask me how i know....

hope i've helped
-Ryan

Thanks im back to work now for the next 4 days and i will try it when i get off wednesday.

ALEXANDERJASON
03-08-2007, 10:00 AM
Originally posted by jrafter

i ended up with a 50 pilot jet and i started to see a good respond.I also got a fuel screw from and 04 250ex that i could adjust when it was runing with out any problems and that seemed to help.




IS THIS A LONGER FUEL SCREW THAT YOU CAN ADJUST WITHOUT ANY TOOLS?? I AM HAVING SUCH A HARD TIME GETTING TO THAT STINKING THING, AND ALL THE AFTERMARKET SCREWS NEVER LIST THE 250EX AS ONE OF THE BIKES IT WILL WORK WITH. I HAVE AN '07 250EX.

stew2010
03-08-2007, 04:29 PM
u should be able to find one thats compatable with your carb..theres gotta be one that fits it

shleprock
03-08-2007, 04:32 PM
I adjusted the main on mine witch i sugjest and if something isnt the way you want it after putting the jets in then its 85% of the time the jet your using dont mess with everthing else just the jet your messing with cause after you mess with all that crap you dont know whats wrong at least this way you know its the jet

ALEXANDERJASON
03-08-2007, 07:33 PM
Originally posted by stew2010
u should be able to find one thats compatable with your carb..theres gotta be one that fits it

I THOUGHT SO TOO, OR AT LEAST I THOUGHT OF THE THOUSANDS OF PEOPLE THAT BROWSE THESE FORUMS, SOMEONE WOULD CHIME IN AND TELL ME WHERE AND WHAT TO GET. I HAVE EMAILED A DOZEN DIFFERENT EXTENDED FUEL SCREW MAKERS, AND I EITHER DON'T GET AN ANSWER, OR I GET THE SAME ANSWER IN THE DESCRIPTION (AS IF I COULDN'T READ IT).

ANYONE HAVE A CLUE OR HAVE ONE ON THEIR 250EX???

stew2010
03-09-2007, 12:51 PM
i forget what kind of carb it is but there has to be a dirtbike or motorcycle that has the same carb, but do they make a fuel screw ?.....i'll do some researchin' probly post again tomorrow