Question for all 300 EX riders

[cain73]

I have an 01 300 EX. when ever I hit the throttle real hard on the bottom end it will bog down and die, but if I ease into it then hit it it will perform o.k. does any one else have this prob? is it with all 300 ex's or is there a prob with mine, and if so how do I fix it?
Any suggestions are appreciated since I am new to this and looking for knowledge. Thanks

[300exOH]

Is it stock or does it have any mods? If there are mods you may need to jet it. Have you checked the plug? Need a little more info to be of any real help.

[Maxxed out]

Hey Its probably normal.:huh

[Maxxed out]

well now that i think about it.. it could be jetting.. or pretty much anything! we need more info.

[jokerman_28]

sounds like a dirty carburator. clean your air filter more often also. and clean your carburator. check your carb every 4 months or so. clean your air filter after every 2-3 hours. or every 1-1/2 hours in dusty conditions.

[cain73]

here is more info so hopefully you can help me.

enginge is stock for now.
air filter is cleaned often and frequently inspected to make sure that's not a problem.
I haven't cleaned the carb yet.
the plug is burning fine, so the air/fuel mix is good.
any other ideas or info needed please let me know.

[jay's 300]

Sound like your jetting's off. Mine never done that stock. :D

[300exOH]

Could even be electrical. Maybe the stator or the CDI? Your jetting could still be off. The plug can look fine after normal riding but if you check it properly your problem may show up. Try testing it with a warm engine and put a new plug in and test it at idle, 3/4 throttle and full throttle. There's a good article about jetting in the tech articles taht may help you test it.

[300EXrider02]

well I read all your opsts and some are close

I had the same problem

first check your plug, it will tell you what happening to it

I did many things and now its working pretty darn good

usually that means your fuel/air mixture screw is running way to rich, turn it down about a full turn or more

possibly go to a 40 or 42 pilot jet...

it might also be that your needle jet is running fat, if the other thing doesnt work, put your clip one up on the needle

[josh330ex]

Well i put a Dg full exhaust and k@n air filter in my 300 ex it hurt the speed i think the torque is better but speed is killed a 450 foreman about out ran me thats sad do i need to jet my carb would that help

[pimpin330ex]

josh330ex u deffinetly have to rejet if you dident allready

[300exguy125]

hey i have a 2000 300ex and it is normally for them to do this they bog because they get to much gas when you hit it fast i thought it was not normal to until i read about it in atv action that most fourstrokes bog when you hit the gas fast also my friend has a 2002 300ex and he thought there was somthin wrong with his i told him it was normal befoe i knew it was normal i tried to fix it by idleing it up with the idling screw it worked but i dont no if you want to do that or live with it

[krt400ex]

if ur bike is still cold then it is normal. warmed up means that is has run for 5min. at about 1/4 throttle. those bikes take for ever tho warm up. it could be ur plug or else ur pilot sounds lean, but it could be ur main too. when i put the pipe on mine, it started to stumble like that and all i did was put in a bigger main and that cured it. it could be a number of things, u just need to test everything possible to find out what it is.

[krt400ex]

Originally posted by 300exguy125
hey i have a 2000 300ex and it is normally for them to do this they bog because they get to much gas when you hit it fast i thought it was not normal to until i read about it in atv action that most fourstrokes bog when you hit the gas fast also my friend has a 2002 300ex and he thought there was somthin wrong with his i told him it was normal befoe i knew it was normal i tried to fix it by idleing it up with the idling screw it worked but i dont no if you want to do that or live with it

it happened to me a couple of weeks ago. if it gets idling to low then it will stumble bad. u don't want it to idle too high though, just turn up the idle till it stops stumbling when u hit the throttle.

FYI ATV Action was way off there. four strokes only stumble like that if there is something wrong. i never liked ATV Action. they do not always get there facts right. have u read the test off the ltr 450?

#1 they were the only mag that said that the ltr has gobs off torque and no top end.

#2 that is wrong, i have yet to talk to a owner of an ltr that has not agreed that the ltr is very soft off the bottom. magazines do make mistakes but i have found that it is too often for atv action.

[81 clark racing]

clean ur carb and adj ur jetting also who ever said its normal ur wrong. only unless its when u first start it when the motors cold my 300ex never did that so looks like a few of u got that problem

[jonboy]

When I first got my Lakota it did the same thing. I took it to the dealer and they told me they just adjusted the air/fuel mix screw. When you hit it hard it is getting alot of air at once and the fuel cant catch up in time,which starves it out and kills the quad. Might be some food for thought

[bwamos]

Originally posted by cain73
I have an 01 300 EX. when ever I hit the throttle real hard on the bottom end it will bog down and die, but if I ease into it then hit it it will perform o.k. does any one else have this prob? is it with all 300 ex's or is there a prob with mine, and if so how do I fix it?
Any suggestions are appreciated since I am new to this and looking for knowledge. Thanks

List us every motor modification you have. Filter, pipe, airbox lid off, air box lid punched, cam, etc... anyhting that could change air flow.

We can give you a pretty close guesstimate on what your jetting should be.

Also, pull the black plastic cover off of the side of the carburetor. Check to make sure the compresion arm didn't slip off of the accelerator pump needle. Common problem. They fab'd it kinda funky. Looking at the side it will be on the lower left. (bottom rear).

[josh330ex]

I can barely see the cracks but there on it so its losein air anyone know where i can buy a housein or would a 400 ex carb work i have one.......