I just bought an 06 yfz 450 an would soon like to put more mods on the quad. I am not sure how jetting works on four strokes like they do on 2 strokes. Do I have to rejet it for every aftermarket part I put on like intake and exhaust and cams or one jet and I'm good? Any help is great. Also I have noticed white smoke when I get it started I dont think it's just because it's cold it might be because its burning coolant and has a blown head gasket or rings. Please help thanks.