I pulled my plug the other day to see what it looked like and it was faint grey almost white. Installed it back checked my valves and ran at idle for nearly 5 minutes revving to half throttle a few times. Pulled the plug and it’s pretty black. I’m running a Lexx Mxe slip on, no air box lid with moose filter. Checked my carb and the main is a AB168, 42 pilot screw and 2-1/2 on the air/fuel screw stock needle position, 740 elevation . Question is what does the AB stand for? And does this sound like the right jetting 168 seems to be alot compared to the stock 148. I’m installing a HD cam chain and stage 1 hotcam and want the jetting right before starting