Hi Iowayguy The plug being dark really is not telling you anything . A plug changes color as you reduce the throttle if you want to check the main jet you have to run down the road at full throttle and pull the clutch and hit the kill switch coast to a stop and read the plug it will cahnge color as your coming in your driveway . So to fine tun you need to take plug reading at different throttle positions . And your plug should just have a hint of color if its spot on closer to looking new. It takes many hours to tune a motor spot on. And street riding its hard to do that. I would either drop the main to 125 or lower the needle a notch. And the adjusting the screw will help if you have hesitation . All these things work together from idle to wide open and all motors are not the same . I set up 2 2004 YAM YFZ s with same pipe and all mods the same and one would not run just wright so I had to make them just a touch different. If the bike seems to run good but burning to much fuel just make small changes to the needle and the main and then fine tun with the screw. I hope this helps but again all motors are not the same and the set up everyone talks about on here is a good base line. That is why I prefer the Jet kits on the markets they have a new needle and many jets to choose from for what your doing but there directions also are just a starting point .

 

do you have the n1tc needle? what position is the clip on? mine is on the third... runs great, might have to try runnin with the air box lid off for an experiment.. uni air filter helped for sure, i have the lid on still, but i have the kdx200 snorkel on it..

 

i have a complete big gun exhaust, just put the uni air filter on last night.. mine runs great...