My FA50 seems to run fine but on downhills i can hear it bogging ...i attached pics of my piston and spark....am i running too rich? i have a 60cc kit, up jetted the stock carb to 95 main jet and 17.5 idle jet. stock air filter with holes drilled in cover. stock exhaust I'm putting on a shaved cylinder head soon with a cooler spark plug. please let me know if i should maybe adjust the throttle needle to be leaner? if so how far should i move clip since its currently in the middle position..