fouled plugs, what to do.

[dank]

ok, ive grown sick of replacing plugs. and in my frustrated state i would reatehr not take the time to dig through old posts to find what i want. i have an 03 ec250 with a 42 or 42 pilot (i cant remember which right off hand) and a 178 main, and who knows what needle (somebody thought SAE tools would work on the retaining screw, turns out they were wrong :/) and i keep fouling out plugs. its like ill put in a new plug (br8es) and it will run for a week or two, i get the bike out the very next day, start it, warm it up like normal, it runs for a while, then fizzles out and dies like i ran out of gas. i try for a bit to bring her back to life, then go get my extra plug, put it in, and presto, it works. the old plug's insulator is black, and theirs carbon build up on the rest of it. so do i go down a size on the pilot? the main? do i find a way to get the needle out and move the clip up? the air screw is about 2 and a quarter turns out as is,and it still does this. any help would make me very happy.

[Brian]

Has it fouled at small throttle openings? If so go with a smaller pilot.
You should read this thread/article, you can test to see if you pilot is to big or to small.
http://www.thumpertalk.com/forum/thr...rich-read-here

Its going to be a real pain to get that "bolt" out of the slide. But it needs to be done. See if you can find some pliers or vice grips that are long and narrow enough to get a bite on it. I've had good luck with vice grips with rounded off bolts.

[Silver]

Dank,

I had a 01 did similar things.Mine ended up being a bad cdi. It was jetted a little rich and jetting it down did help some but still fouled plugs until I put in a new cdi.

[dank]

that thread should be in a sticky. definately. thank you. looks like ive got lots of digging to do. now i have another question. aside from the CDI (which could be, but i hope not) could i do the pilot jetting on the stand? most of my riding is done at no more than 2/3 throttle, and most under a half, so i think my problem may be the pilot. could i do the pilot and air screw on the stand? i have my shock at the shop for service now, and it'll be there for about a week, so im gunna be doin some greasing and lubing on the poor girl.

[Brian]

Yup you could do it on the stand. Let it warm up first before you start messing with the air screw.

[dank]

thankya much! now i have something to do besides clean and lube while my shock is away! man, i really need to get a trials bike......

[moto9]

Originally Posted by dank

thankya much! now i have something to do besides clean and lube while my shock is away! man, i really need to get a trials bike......

I have jetted 4 GG bikes so far two 09's and one 08.
Here's my humble suggestion, if were talking only a jetting issue!
Get these pilots 38, 40, 42, 45,
Main jets 170, 172, 175, 178, 180

Take a day out at your favorite ride area with all the tools to get at the carb and start testing.
since your working with smaller throttle openings I would concentrate on the pilot and needle.
if your at a 40 and still having issues it's probable the needle, and/or clip position.
What I have found is that the carb has the right pilot, but...the needle is allowing too much fuel to dump in at smaller throttle openings....I ran into this issue on 2 out of the 3 bikes.
If that's the case drop the needle, if you end up with the clip at the top, then move to a leaner main jet and place the clip 3 down and start the process all over again.
All the while your doing this, check the plug for color change., feel how the bike's power is responding...better or worse?
Those two will get into the ballpark, then you can finish up with some fine tuning.

[moto9]

Forgot one other thing, the float level was out of wack on all 3 bikes
Here's how I set the level...
I continued to bend the tab up until I could tilt the carb sideways at a 10 to 15 degree angle with no leakage.
Then I did a few wfo runs to make sure it wasn't starving for fuel..they did'nt