300ex stumbling problems

[justhavinfun]

...hi guys..great site you got here ...guess i'm the fng...i just bought an 02 300ex and after climbing a small hill or running a trail on and off the throttle..i get a dead spot when i first hit the throttle..like it runs out of gas for a second..pull in the clutch ...rev it up and then its fine again...as far as i know its all stock except a k&n filter..dont know if it was rejetted but wot it runs great...i'm new to the quad thing but have been working on cars all my life...is it possible the float is bad or needs adjustment?..or do they even have an adjustment?

[zeppelin]

did you try cleaning tour carb yet, maybe your fuel/air mix is way off, does it back fire, is your filter clean, what does your spark plug look like, i kinda doubt its the float, i would at least check all these things and post the results before worring about the float

[justhavinfun]

..hav'nt cleaned the carb yet...filter is clean and the plug shows it burning a tad lean...other than the dead spot every once in awhile when getting back on the throttle it runs great..wasn't sure on the float it just acts the same way a car would with the float level to low

[zeppelin]

k then, when you take your carb off to clean it look and see what size the main jet is, im not sure what the stock size is right now, but im sure someone on here knows, and also richen your fuel screw when you have the carb off your bike

[justhavinfun]

..thanks...i'll get the carb off tomorrow after work

[Sjorge450R]

the main jet on the 300ex is a 122. After a K&N filter is put on you are supposed to rejet. (I never did.) You have to rejet because when you put that filter on it is giving the bike more air flow and you need to richen the plug. One size up on the jet is perfect. My dealer told me that the next size is a 127.5

[bwamos]

Make sure your accelerator pump is working.

If not, sometimes on the 300ex carbs, the compression arm will slip off of the needle. You will see it under the black plastic sidecover. Bottom-rear.

[justhavinfun]

pulled the carb off today everything is nice and clean..and the acclerator pump is working fine..i see were it could slip off the needle thanks...it does have the stock .122 main jet..i'm going to stop tomorrow and get the next size bigger...should i also put in a larger pilot jet?...

[hondardr4life]

Don't touch the pilot. And I see your from SR, PA. I live in Prospect. Im a sophmore at the high school. I'll PM you, I probablly know who you are.

[justhavinfun]

..ok i'll leave the pilot alone..and i probably graduated high school around the time you where born...lol...

[hondardr4life]

Oh, lol I figuerd you were a kid in my school.

[justhavinfun]

...lol...i wish i still was!!!!!! high school was a blast

[bwamos]

Your main jet really only affects you above 75% throttle (it has secondary effect everywhere, but mainly in the top 25%.

Air Screw/Pilot (idle/25%), Needle (25%-75%), Main (75%-100%)

Try turning the air screw out a 1/2 turn if the dead spot is right at the bottom of the throttle. If it's between 1/4 and 1/2 throttle where it's hitting the dead spot.. try moving the needle up one spot. (clip down 1 notch).

You probably are already familiar since you had it torn apart.. but just incase, you access the needle from the top of the carb, in the slide. It will have several notches in it.. and a c-clip retainer that is used to adjust it's position up and down.

[justhavinfun]

...well i put a .125 jet in today and turned the air/fuel screw out half a turn...runs great now...no dead spot and runs even better at w.o.t....thanks for all the help..i'm sure i'll have more ?'s in the future...thanks again

[Sjorge450R]

No problem. If it wasnt for this site I would have spent $600 for a rear shock, instead I got a $150 raptor shock... would have never known to do this.... This site is better than calling a shop or dealer ship because you get more responses from different opions. If you would have taken your quad to the dealer ship it would have costed you big time.... :rolleyes:
Steve

[bwamos]

Glad to hear you got her running good.

Carb tuning is a pain until you learn how to read the symptoms. After that, it's easy as pie.

[justhavinfun]

...definatly a great site and there's nothing better than talking to ppl with experience and have tried different things...now knowing that the air/fuel screw controls the first part of the throttle i probably could have gotten away with just turning it but it was running a tad lean anyway plus wot it runs better than it ever did..i never figured when changing a jet that you would notice the power gain...but i was wrong...like i said this is all new to me...if it was a 4 barrel holley i could have tuned it with no problem...lol...thanks