Hey I have an issue with my 2013 450x bike has low miles . This is gona be long pls be patient , so to sum this up quick I had a head gasket blow so I did a rebuild , new valve stem seals , new piston/ rings gaskets , cam chain . ball honed the cylinder . while the carb was easily accessible I installed a r&d flex screw set it at 2 turns out . bike fired right up went threw the break in procedure . Bike now smokes heavy black smoke when I am hard on the throttle . prior to this rebuild the bike ran excellent . the bike still starts excellent , idles perfect does not pop on decal . I never changed my jetting when I had the carb apart just cleaned it . I have since taken the carb off cleaned it again , checked the float height , checked the fuel screw , replaced the slide o ring seal and the bike replaced the spark plug , checked engine timing , cleaned air filter , checked all hoses into the airbox checked the valve clearances all of which were perfect still smokes black smoke !
I am puzzled ! few days ago I had the coil, stator , and cdi checked with a resistance ,meter all fine there as well . bike has a big gun exhaust , and air box mod, smog block off kit .
current jetting is
165 main
42 pilot
ncvs needle 4 position
r&d flex fuel screw 2-1/4 turns out