Is my plug color too lean?

I'm trying to adjust my mixture since I put on a new pipe and filter. I moved the clip up 1 notch to lean it out because it was really bogged out before. Now it's running a little better, but still 4 stroking at 1/2 and 3/4 throttle, but fine WOT. Does this mean I can lean it out another notch? The color is a light tan color, which I thought was normal and how it should be, so why is it still 4 stroking? I should also add that this plug has about 20 miles on it, so it is very new, will this make a difference? Will it 4 stroke at all if the mixture is perfect or should it not 4 stroke at all if I have it dialed in correctly? Look at the picture and let me know what you think. Thanks.

Go look on you tube what is 4 stroking, there is a good video that explains it and you can hear it too. What happens is the piston does 4 strokes instead of 2 because there is too much fuel to air ratio in the mixture. To correct it, adjust the carb's c clip up until it becomes leaner. That's what I know about it, but mine is still 4 stroking and I have my clip on the highest notch. I have a smaller jet that I can replace my .7 stock jet with, but I'm not sure if I am getting too lean or if it is safe to go a little more. Each notch I lean it out more, I get more power, but I'm not sure how far is too far if my plug color is getting lighter but still 4 stroking.