KDXRIDER.NET

I pretty much have my jetting dialed in correctly. There are a few small things i am working out though. I can go about 10 hours of hard riding before i have to change a plug. I had a bad one in the bike and i put a new one in, the bike is more responsive and will finally wheelie in 3rd gear. (not that im good at doing them anyway). I am normally racing with my buddy in my trails. So most of the time i am accelerating quickly and in higher gears. my question is since my plug is black should i try dropping the 145 main to a 142? I thought it may be my pilot so i turned out my air screw about 1/4 of a turn but it has no effect which leads me to believe i am normally past the point at which the air screw and pilot jet affect my jetting. Does changing the jets seem like a good idea?

Also, i might as well do it now if i am to change from 32:1 to 40:1 then what changes in my jetting should i make? Thanks

"I can go about 10 hours of hard riding before i have to change a plug"
Do you change the plug every 10hrs, just to change or is there a performance problem. You should be getting a hellavalot more that 10hrs.
You have to do a plug chop @WOT w/a new plug to find out. Have you tried raising or lowering the needle??

You will have to do a full throttle plug chop to correctly check the main. Most trail riders foul the plug when the throttle is between closed and half. Of course this all ASSUMES the air filter is not over oiled, that the float level is correct, that the gap is correct, that the CDI and coil etc. are all firing correctly, the plug has that cap on (remember this one Ryan?). As for the pilot circuit, if your AS adjusts idle to it's best between the 3/4 and 2 turns out that would mean the pilot is the correct size. I would think most of your riding and fouling problem would be mostly on the needle's function of the circuit. Might want to raise the clip to #2 or change needle profiles entirely.

What size pilot are you using?

Maybe I'm missing something, but won't going from 40 parts gas/1 part oil to 32 parts gas/1 part oil translate to less gas per unit volume, which is leaner from a fuel/air perspective?

Ten hours on a plug is nothing. I agree with comments associated with raising the clip on the needle. From what you (Ryan) have written in some of the threads you are definately rich somewhere.

I had the impression you had no problems with plugs fouling until you got over 3/4 throttle. Was this incorrect??? I suppose the other thing I was confused on is I thought you drove a 200 - I see a 220 in your signature.

I can easily run a plug for 1000 miles without any issues. Don't know what this is in hours but for an old guy it is quite a few. 60-75 hours maybe.

i know 10 hours is low, thats why i know i have a problem. I had it jetted but it seems a bit off still. Everything electrical is right. AS far as my pilot i am running a 42. Since my jetting isnt as far off as it was before would i be able to switch to 40:1 and then jet it so i dont have to do it twice? As far as i can tell i really dont foul the plug when i am going slow, the bike does smoke a little more when i am doing higher speeds and more open throttle. Like i said i race 90% of the time when i ride. i am over 50% throttle 60% of the time when i am racing. I dont rev it out i just open it up to accelerate quickly.

If that's the case you are way past the pilot jet and diameter section of the needle. You are in the taper of the needle. Raise the clip to #2 or get a slightly leaner needle. I run a DEK-4 up to 75 degrees then I have to drop to a CEK-3 for high temps or the plug will start getting pretty dark. I ride mainly in the 1/4 - 3/4 throttle range.

Ryan, you should read this:

http://justkdx.dirtrider.net/carbtuning.html