I just installed my JD jet kit in my 2004 YZ250F. I followed the recomended settings for Sea level. The bike has a new piston (stock Compression) and Eric Gore did a stage 1 valve job,porting,kibble white valves. The bike is idling ok but going through the gears it cut off on me in 4th gear 3/4 throttle rolled it home looked it over, the plug is black(not wet). Put the plug back in and the bike fired right up. Am I lean or rich? What do you suggest. My air temp here is about 50 degrees and I am at about sea level. Thanks for your help!