KX 250 Fouling plugs! PLEASE HELP

[earthvssoup26]

Here's my problem. i have an 03 kx250 and when i first got it last year i probably rode it 15 times without ever fouling a plug. now it fouls a plug every 2 times i ride it...sometimes after only 1 ride. i feel like i give it enough throttle to keep it clean. here's what happens.....i ride it and everything is fine. but next time i start it, it starts right up, so i warm it up , then when i give it a little gas it bogs and dies. fouled plug. why is it getting fouled when it just sits in the carport for a week?

[Faded]

There are a number of possibilities that could attribute to your problem. It could be fuel/oil type used, variances in jetting due to temperature change, improper float level from lack of maintenance...just to name a few. Sounds like the bike is loading up from one reason or another, or a combination of any of the above reasons. It's best to try and think what has changed since last year and start narrowing down the possibilities.

[wFo250]

How old is your gas that you run? You may know this already but fuel ( race fuel or 89pump?) wont stay fresh very long. Especially mix. What I do is...for what it's worth.. keep one container of fuel only and another for mixing (I use a combination of 108-112 race gas+93 pump@52:1 golden spectro) just what I am going to use that day. I also turn the petcock off and lay my bike down to drain the bowl when I'm done riding. My buddys' 96 rm125 would foul out every 15min.!! No kidding! AND I had fouling probs(not as bad as him) on my oo'kx and since we changed to this type of fuel and seperate storage method, neither one of us has fouled out once in two years. I haven't even changed my plug in a YEAR!! I probably better do that.....anyway, hope you get 'er runnin' right, and RIDE-ON MY BRUTHA!!

[Crogg]

Originally posted by earthvssoup26
Here's my problem. i have an 03 kx250 and when i first got it last year i probably rode it 15 times without ever fouling a plug. now it fouls a plug every 2 times i ride it...sometimes after only 1 ride. i feel like i give it enough throttle to keep it clean. here's what happens.....i ride it and everything is fine. but next time i start it, it starts right up, so i warm it up , then when i give it a little gas it bogs and dies. fouled plug. why is it getting fouled when it just sits in the carport for a week?

What are your jetting specs? I have one in the same area as you...(elevation) 155 main, 48 pilot. nalh needle in 2nd position (stock needle is a nafh) and air screw 2 turns out. Verified jetting with wide band 02 sensor on the dyno. Besure to check reeds, float level ect.. what Faded said!!!

[Faded]

Originally posted by Crogg
Verified jetting with wide band 02 sensor on the dyno.

Crogg, you so lucky! Wish I lived within spitting distance of thay type of equipment...

[earthvssoup26]

man, i know nothing of bikes. maybe woody crf will know how to adjust stuff.

[Faded]

Originally posted by earthvssoup26
maybe woody crf will know how to adjust stuff.

It's a long shot, but you could try.

[Woody_393]

Originally posted by Faded
It's a long shot, but you could try.

Oh man... that was LOOOWWW. Ya big jerk.

Yeah EVS, I can give you a hand with that. Not sure when we'll be riding next though. You going to be free on monday for a boot out at Tooele? We could do it then. I can have you come by my house first and check it all out and go from there.

Also, when was the last time you cleaned the air filter? If it's been a while... Same problem. I'm betting on filter.

The only problem with the Crogg certified jetting specs is that your head's been ported hasn't it? Which means if you jetting was on with the ported head, then it will be leaner then those specs (since I don't know what Crogg's got done to his) by default. However, again, if you filter is DIRTY, all of this doesn't matter. Dirty filter means less air flow which equals Lots of gas with no air (or a rich condition), which would foul plugs like mad.

Anyway, let me know and either way we can fix you up on monday.

[earthvssoup26]

sure i'll go out to tooele on monday. air filter? i bought a new one and put it in like 4 rides ago...maybe 5.

[Woody_393]

Guess we'll see??

[Crogg]

Originally posted by Woody_CRF
Oh man... that was LOOOWWW. Ya big jerk.

Yeah EVS, I can give you a hand with that. Not sure when we'll be riding next though. You going to be free on monday for a boot out at Tooele? We could do it then. I can have you come by my house first and check it all out and go from there.

Also, when was the last time you cleaned the air filter? If it's been a while... Same problem. I'm betting on filter.

The only problem with the Crogg certified jetting specs is that your head's been ported hasn't it? Which means if you jetting was on with the ported head, then it will be leaner then those specs (since I don't know what Crogg's got done to his) by default. However, again, if you filter is DIRTY, all of this doesn't matter. Dirty filter means less air flow which equals Lots of gas with no air (or a rich condition), which would foul plugs like mad.

Anyway, let me know and either way we can fix you up on monday.

Woodster always the thinkster Those specs are for a stock 03 KX250...which really wakes it up!!! Try it! You'll never foul a plug again...provided you clean your airfilter more than once every blue moon, fresh premix yada yada yada

[Woody_393]

Something tells me I'm taking hits from all sides

We'll try those settings if we can get the jets.

BTW, KX250 - Mikuni or Kehein?

[Faded]

Originally posted by Woody_CRF
Something tells me I'm taking hits from all sides

We'll try those settings if we can get the jets.

BTW, KX250 - Mikuni or Kehein?

38mm Keihin PWK, the pimp stuff... BTW, not to be a jerk again (sorry for the first one ), but ported head? : I think you've been hanging around too many four strokes.

[earthvssoup26]

har. i think he meant "milled head"

[Woody_393]

Screw all of you E vs S bring it over and we'll have a look.

[char393]

Originally posted by Woody_CRF
Screw all of you E vs S bring it over and we'll have a look.

Woody! : Why I never....


LMAO....they sure got a reaction out of you.

[Woody_393]

Well, here's the deal. I don't hang out/w or work on 2 strokes. so yeah they are right, 4 strokes for me all the way... DUH!

[Woody_393]

Doh, forgot the smiles on that last post

[psycho393]

well I say if he's a fourstroke guy he can only hurt the priceless smoker