back fireing

[Honda10]

ok I had a 115 keilm main jet in my 05 250ex with HMF,k&n, and open airbox. I was backfireing and drowning in gas, so much that it just shut off. So now I put the 112 main in also keilm and it still backfires but it is not drown. I have the clip on the 3rd out of 3 positions. What do I do?

[250excrf250r]

try going down a postion or 2 if that doesnt work then go to a 110 main

[Honda10]

I am running a full pipe filter and open airbox. would the top(first position) be the point of the needle or the opposite side. Plus was I suppose to get an aftermarket needle that has more positions, cause stock only has three.

[ryanh250ex]

put the e-clip down one notch, and back down your main to a 110 or 112. Its also possible that your main jet has vibrated itself loose- this happened to me twice.

Unless they made a revision later on the stock needle should have six slots, not three.....

[Honda10]

I have an 05 and it only has three slots and it is no the one closest to the point and have the 112 main in, I do not havea 110 main i have to order it. But Is that needle c-clip position right.

[Honda10]

bump

[Honda10]

I just put the clip on the bottom slot, the leanest part of the needle Furthest from the needle point. I have the 112 main in, and I tested it and reved it and it still backfires, I dont understand. Do I need a piolet jet, adjust the fuel screw, or get a new needle that has more the 3 clip slots. Sorry for bugging you guys about this, but can someone awnser my question?

[250excrf250r]

change yopur spark plug and put needlde on all 3 and try iut

[Honda10]

Originally posted by 250excrf250r
change yopur spark plug and put needlde on all 3 and try iut

what do you mean by putting the needle on all three.

[250excrf250r]

Originally posted by Honda10
what do you mean by putting the needle on all three.
yes after u change the spark plug retry all of the but buy a few plugs just incae u foul them.
this happened to my atv and my friends his had something cought. but hers the story....
one night he slept over and put his atv in my garage the battery was dead so the bike hadnt been started in months. we start it at home and run it. we drive 45mins away and his bike wont start. we change the plkug and its fine for 1.5 hours then it literally would not move. in gear. in N it would rev up and pop. later to present it is fine .
reason i tell u the story is his kind of atv was just fouling plugs 1 after another now its not, so if u change it that will help i said try all 3 slots because u still need toget the correct jetting. if that dont work go down to a 110 main. but if that doesnt work then i would contact the dealer because i dont know wat else to say if it dont work. but the 112 and 110 is for a 250ex with FULL pipe with no sparky. airfilter w/o lid.

lastly wat u could of done is messed around withe the fuel or air screw without nowsing it so i would take a day and just play around with it. make a cheaklist of possible things and if it works then ur set if it doesnt then move to next senerio.

if worse comes to worse drop the bike off at the dealer and tell them to jet the carb.

[Honda10]

thanks you very much for the help, but my for wheeler starts fine, maybe I just need to buy a pilot jet.

[ryanh250ex]

OK, it's now come to my attention that later (pre-07's) 250's have 3-slotted needles. Go back to the middle notch, as maybe your richness issue in your first post was because of a overly rich needle setting.

Plug reading is almost useless nowadays because of all of the detergents and additives in gas. If your plug is old or is soaked in gas, put in a new one, and start over.

How does the bike run when you're in gear and on the throttle?

Try backing the fuel screw out a turn or two, and see what that changes. YOU DO NOT NEED A BIGGER PILOT JET.

[Honda10]

Ok,thank you I will try that. I in gear it runs fine, it just bogs slitly in 4 And 5 gear up hill. And are you saying back the screw out from all the way in position or where it is at now? Thank You

[ryanh250ex]

First back it all the way in, noting how many turns it takes (360 degrees= 1 complete turn) to get the screw all the way in (you'll know it's all the way in when you can't turn it anymore), then turn it back out to whatever it was, plus a half turn, whole turn, whatever is necessary.

jetting is not affected by gear, it is affected by throttle setting. Telling me it bogs in 4th and 5th is useless.

[Honda10]

ok, well then at 3/4 to full throttle it bogs in the those gears.

[exrider12]

that would be your main jet and what kind of bog is it? Like starving for fuel or like its getting to much?

I would have to say too much fuel for a bog, too little it would stutter or want to cut out.

[Honda10]

I am just going to buy a dynojet kit, cuz no matter what I havetried it still backfires and I need a smaller main jet that I dont have. Is this a good idea and plus it comes with instructions.
.Ur opinions on dyno jet and and if they are good or not would be greatly appretiated.






I cant do anything with the jets I have now. So if anyone wants kehlim jets 112-125 just pm me

[ryanh250ex]

Originally posted by Honda10
I am just going to buy a dynojet kit, cuz no matter what I havetried it still backfires and I need a smaller main jet that I dont have. Is this a good idea and plus it comes with instructions.
.Ur opinions on dyno jet and and if they are good or not would be greatly appretiated.




I cant do anything with the jets I have now. So if anyone wants kehlim jets 112-125 just pm me

Get a K&N , i can't help you if you get a dynojet.

Dont just throw money and parts at a problem. What is your current jetting setup? what problems does it still have?

[Honda10]

I have a k&n, but my current jetting setting is 112 keilm main, clip on the middle out of 3 postions and fuel screw is two turns out the problem is that it is backfireing like crazy and I have tried putting the clip on the all three postions none of them cure the backfireing. So I think I need to go down a main jet.

[ryanh250ex]

Did you experiment with the fuel screw?

I'm not sure what your problem is, I'm wondering if its something like a vacuum or exhaust leak. Go down a main jet or two.

[Honda10]

I have played with the fuel it can not fix, it is a huge backfire. Thats the problem so now I have to order 110 or lower off jets r us cuz I didnt order them with the others so should I do that or get the dyno jet. What is ur opinion on what to do, dyno jet or can the the jets at jets r us do just as good?

[Honda10]

Anyone?

[ryanh250ex]

Originally posted by Honda10
Anyone?

I just told you what to do, order a K&N jet kit, or head to the dealer and order a 105, 108, and 110- end of discussion.

So you are telling me the problem neither got better nor worse when you added/subtracted fuel using the fuel screw?

Are you SURE you don't have any kind of vacuum/exhaust leak? Because i'm not entirely convinced that your problem is jetting related. unless you really d*cked something up that you havent told us yet, the problem should at least become better or worse with different jetting setups.

[Honda10]

sorry, i thought you m ge a k&N airfiltr. I wanted to know if I would need an after market needle that has more slots.

[exrider12]

check your exhaust! if its not tight to the cylinder it will back fire. there is a gasket i think where the exhaust flange connects to the cylinder, make sure you didnt damage it when putting the exhaust on.

[250excrf250r]

wat to do is start the atv then cover the end cap with the palm of ur ahnd and listen for air coming out of were the cylinder / header meet if there is a sound then tighten the bolts if there is no sound the it doesnt have to do with exhaust

[ryanh250ex]

Originally posted by Honda10
sorry, i thought you m ge a k&N airfiltr. I wanted to know if I would need an after market needle that has more slots.

No, K&N Jet kit.

A needle with more slots would be ideal, but I dont even know if thats your problem. It sounds more like you have a exhaust leak.

[Honda10]

I am going to test tommorow but I do need a lower main jet because gas is spitting out of my exauhst when i rev it, so I am in the procces of ordering a 105,108, and 110 main. But I dont know if I should spend the extra $30 to get the K&N jet kit orjust buy t three main jets.

[ryanh250ex]

Originally posted by Honda10
I am going to test tommorow but I do need a lower main jet because gas is spitting out of my exauhst when i rev it, so I am in the procces of ordering a 105,108, and 110 main. But I dont know if I should spend the extra $30 to get the K&N jet kit orjust buy t three main jets.

There is NO WAY you could possibly be that rich unless something else is amiss. Open up the carb, turn it upside down and check to make sure the main hasnt worked itself loose or free. My main jet somehow managed to come off twice, made the bike run rediculously rich at anything over 1/4 throttle.

[prairiemonster]

Same old question same old answer same old results.
Honda 10 I had to pm you on this one.My big mouth/head/thoughts/ideas/lack of knowledge gets me into trouble on this site:rolleyes:

[ryanh250ex]

Originally posted by prairiemonster
Same old question same old answer same old results.
Honda 10 I had to pm you on this one.My big mouth/head/thoughts/ideas/lack of knowledge gets me into trouble on this site:rolleyes:

?????? Can you PM me explaining what you mean?