stalls when full throttle from idle

[jdub03]

Hello, just purchased a 07 250ex and installed a unifilter, no lid or snorkel & a dynojet kit. I installed it as instructed needle 4th position, 106 main. Idled fine everything seemed good except when quickly giving it full throttle it bogs and stalls. I tried lowering the main jet to a 102 and it had the same problem. The tool given to adjust the mixture screw doesn't seem to be working right i can turn it endlessly clockwise to seat it, but it never does. I tried my best to approximate 2 1/2 turns out, but its only a guess right now. Any help would be appreciated. Thanks

[BR16250]

dont just give it full throttle when its idle, work your way up to it and see if the problem continues. or try to warm it up and give it full throttle and see what happens...

[jdub03]

I have warmed it up. I ran it hard for 5-10 min. It runs fine from bottom to top. It just bogs & stalls out when u blip the throttle wide open from idle. This should not happen.

raise the needle by lowering the clip on it. You also may need a jet 1 size bigger but just try the needle.

[jdub03]

I thought the needle controls 1/4 to 3/4 and that part is fine. So your saying I need to be richer. Its not stumbling or sputtering or backfiring when decelerating any where in the rpm band, only off idle when floored does it bog and stall i thought that was a rich condition I could be wrong. The needle in the 4th position is already richer than stock and the stock main was a 95. I have run both a 106 & 102. A 110 is the only richer jet I have left, but that seems a little high. I really dont feel like changing the needle position, but i guess i should give it a try. Thanks for your help. I'll give a try this week.

[250excrf250r]

to start off u shouldnt give it full thorrottle in netral from idle. but u may have but tyhe eclip on the 2nd postion. in other words u went the wroung way with the needle. but thats about all i can think of that could be wrouyng

[ryanh250ex]

I can only help so much because you're using Dynojet stuff. Why people use dynojet when they are not the major brand out there is something I'll never understand...

Secondly, there is NOTHING out there that says you shouldn't or cant go wide open throttle from idle. If you can't you are not tuned properly- no exceptions.

Now regarding your problem, its hard to tell without hearing the bike but if it bogs down that means it is rich somewhere along the fuel curve...if you go to stab the throttle and it makes no sound and just dies then it is lean.

Are you running a stock exhaust?

I'm thinking that it may be the e-clip on the needle...try setting it one notch lower (5th groove from the top, there *should* be 6 grooves)

I need a better description before I can help further.

[jdub03]

Stock exhaust...only mod unifilter & no lid. As stated above it starts right up idles fine. When idling if you roll on throttle there is no problem with the 106, but when you blip the throttle fully open it makes a quick bog noise and stalls. With the 102 once again fine rolling on the throttle, but when blipping the throttle fully open it immediately stalls and I just heard it backfire. Now when driving it through the gears punching it or rolling on the throttle to wot it seems ok. No hesitation, no bogging, power seems about right. It decelerates normal no backfiring or spuddering. I'm gonna move the e-clip down a notch. Thanks for your help. I purchased dynojet because I have used there products before with no problems.

[BR16250]

why do u need to floor it out of idle anyway? i dont see a need for that ever.....

I solved your problem like 5 post ago lol. I had the same problem until I lowered the clip on the needle down 1. Problem solved throttle response better than ever.

[jdub03]

BR16250: Its not that i need to floor it off idle. It's just a sign that its not tuned correct thats all.

FoxHondaRider:
ryanh250ex:
Thanks for your input i'll give it a try when I have a chance.

[ryanh250ex]

Originally posted by jdub03
Stock exhaust...only mod unifilter & no lid. As stated above it starts right up idles fine. When idling if you roll on throttle there is no problem with the 106, but when you blip the throttle fully open it makes a quick bog noise and stalls. With the 102 once again fine rolling on the throttle, but when blipping the throttle fully open it immediately stalls and I just heard it backfire. Now when driving it through the gears punching it or rolling on the throttle to wot it seems ok. No hesitation, no bogging, power seems about right. It decelerates normal no backfiring or spuddering. I'm gonna move the e-clip down a notch. Thanks for your help. I purchased dynojet because I have used there products before with no problems.

I forget which way it goes, the dynojet numbers run either bigger or smaller than the corresponding K&N/Keihin jets...but a backfire is usually a pretty good indicator of a lean condition.

WOT from idle is used in racing or doing stunts. Amazing to see some of you think it's not supposed to be done. :rolleyes:

Let us know if the e-clip change helps.

[BR16250]

when are you ever idle in racing? even in the holeshot your quad is not idle

[jdub03]

Ok, I had a little time to try tuning it today. It was 20 degrees warmer today than last time. I warmed the bike up, rode it around my yard. It was popping a little on deceleration, however the power felt pretty good bottom to top. So I lowered the clip to the 5th position as instructed, but I also put the recommended 106 main in instead of the 102. It struggled to idle and would stall unless i would give it a little throttle If I punched it would hesitate and bog then rev I played with the mixture screw got it the best I could, then turned the idle screw, it had to be completely in for it to idle. I test rode it after warm up. Lost bottom & mid power bogging in the low rpms, . slight loss on top, but no popping. There was a little black smoke coming out the exhaust at idle and when reved. I pulled the air box off and there was a little smoke in it also. I tried moving the needle to the 3rd position. It idled high so i back it off until it was idling good. Still had some black smoke coming out at idle. Power felt weak in the low & mid. Once again top felt the same. So the 4th spot must be the right one. I review dynojets instructions again. (remove slide, squeeze white retainer & remove. Install dynojet needle in 4th groove, using all stock spacers install dynojet washer above e-clip use 106main. I don't remember seeing any stock spacers. The only thing in there was the white retainer, spring,e-clip, non adjustable needle in that order. So instead I tried putting the washer under the e-clip this time there's a groove in the slide that looks like a washer should go there. Started it up idle wanted to die. Had to turn idle screw all the way in to keep it from stalling. Rode it around bottom & mid feel weaker than with the washer in correct spot, but no popping. Top felt better with the 102main. So i parked it and called it a night. I guess I'll flip the washer and run it with the 106 and see how it goes.

[jdub03]

Maybe I'll try and use there recommended jetting with lid on. They say needle 4th 92main. The main seems a little low, but dynojet isn't oem.

[maddmatt02]

first off my man, gthe 250ex isnt gonna be considered a race quad, and there is no clutch to drop when the revs are up anyways, sure you can hold the brake and rev it a bit in first, release the brake and floor it, but again, this is not a race bike. I gues since his is 07 it might have that sportclutch (cant remember what year it came out, think it was 06 or 07) but regardless, most dont. and when do you floor it off idle. think about it, your riing with friends, one wves you down, you cruise over, and stop, talk to him for a minute, put it in first, and you were just idling while talking to him, then you nail the throttle to take off. it happens alot when anyone i know is on one of the 250exs we got down here, not so much on the machines with a clutch, because oull go over backwards if you nail it and drop the clutch, but on a bike you dont have to work the clutch, and doesnt fully grab instantly hen you nail it, it just comes natural.

[jdub03]

07 does have a clutch. I'm not trying to make a race quad. If I wanna go faster I'll hop on my Z. I'm just trying to get a little more to help pull me up hills if i'm on it. I bought it for my girlfriend to ride & friends if they don't have anything. Anyways I just droped the main to 98 its running better overall I'll pull the plug to check it out when I get a chance. I think I'm gonna run it with the lid on. The sucking sound is annoying.

[250excrf250r]

yea u should be at 98 or 102. 106 is for a airfilter w/ air lid on and complete system exhaust with spark arrestor so the 98 or 102 is perfect

[jdub03]

How loud is your yosh.

[250excrf250r]

well with the sparky its like 96-98db but i never use that with out the sparky it is pretty loud not as loud as my dirtbike but the exhaust makes my neigbhors complain and you can hear it from pretty far away and it sounds really good
for a bigger pic go to the "post ur sick 250's' and its on the 8th page last one

[jdub03]

Thanks, I want something as quiet as possible. Supposedly Ac racing has a s/o around 93-95 db's, but I dont know anyone who has used one. Seems like a good quality product.

[ryanh250ex]

Sorry I couldn't get it right for ya. That dynojet system always throws me off. Now that I realize the numbers run smaller for them I can tell you that your issue was being rich, not lean. Your description indicated otherwise, initially.

Even the experienced get it wrong sometimes...

Offtopic, but where in NJ are you located?

[jdub03]

ryanh250ex: No problem, its hard diagnose something over the computer. I live in Rockaway in Morris County.

[maddmatt02]

I wasnt trying to give you crap about your 250 and you thinking its a race quad or anything, I was more pointing it towards the guy saying even at the starting line you dont go from idle to WOT, and that its never necessary.

[jdub03]

madmatt02: No problem

Ryan250ex: If you want to add dynojet to your facts list I believe that dynojet #'s run 4 lower than factory. (ex 96dyno-100factory) going by your factory jet facts.

[ryanh250ex]

Originally posted by jdub03
madmatt02: No problem

Ryan250ex: If you want to add dynojet to your facts list I believe that dynojet #'s run 4 lower than factory. (ex 96dyno-100factory) going by your factory jet facts.

Thanks, will do! :D

[nyyankees3511]

Did you ever figure this out? My stock 250 does the same thing. I think mine is factory lean like all hondas i guess.

[jdub03]

Right now, I'm running needle in the 4th w/ stock pilot, 98main fuel mixture screw 2.5 turns out. I am running a lid now. Only mod is a unifilter. I'm 500ft above sea level and it was 40-50 degree's at the time. I will switch to a 96 when it warms up to 60-70's.

What year is your bike. What parts are you running. Whats your current carb setup. Whats your elevation & Temp.

[nyyankees3511]

I have a 2001 its completely stock, i havent touched the carb at all. Its like 50 degrees here pretty much sea level.

[jdub03]

Your atv shouldn't have the same problem as mine unless you changed the jets. Take your filter off clean it. Take your carb apart clean it. Check the jets stick a thin piece of wire though them to get rid of the any build up. Spray it all down with carb cleaner. Make sure all hoses are in good shape in there correct location. no holes, cracks,etc. If you purchased the atv like this check the needle position & jet sizes. You might as well put a fresh plug in. There only about $2-3.
If your using factory jets use the atv performance facts thread by
ryanh250ex: For stock it says 98 main. Stock pilot, Needle in stock location 3rd. That should work for you if its to lean because its 50 degrees than bump it to a 100. If your using dynojets than probably 96main needle in the 4th with stock filter at 50degree's. Keep in mind the 07's don't have an adjustable needle stock but the dynojet kit comes with it. So the needle position between mine and your could be different. Considering you have the older carb I would stick to ryanh250ex's guide.

[250excrf250r]

Originally posted by jdub03
Your atv shouldn't have the same problem as mine unless you changed the jets. Take your filter off clean it. Take your carb apart clean it. Check the jets stick a thin piece of wire though them to get rid of the any build up. Spray it all down with carb cleaner. Make sure all hoses are in good shape in there correct location. no holes, cracks,etc. If you purchased the atv like this check the needle position & jet sizes. You might as well put a fresh plug in. There only about $2-3.
If your using factory jets use the atv performance facts thread by
ryanh250ex: For stock it says 98 main. Stock pilot, Needle in stock location 3rd. That should work for you if its to lean because its 50 degrees than bump it to a 100. If your using dynojets than probably 96main needle in the 4th with stock filter at 50degree's. Keep in mind the 07's don't have an adjustable needle stock but the dynojet kit comes with it. So the needle position between mine and your could be different. Considering you have the older carb I would stick to ryanh250ex's guide.


i agrree wit all that how wever if u do clean ur filter scince its a foam filter u have to buy filter oil $7 but the main reason is it is lean from the factory so just buy a new jet kit and install that, for get about wat the bike havs just replace every thing and honestly just get a new filter. if u don want to spend alot of money the "no toil" air filter off motosport.com is on $20 + u neeed filter oil.