hey there !looking for some input. i have put a2004 250x in my sons race quad. we went with the x for the estart as he is only 100lbs. and has trouble kicking it over.also the trans ratio i felt would suit the mini quad better.we had the valve issues with it within 2hrs and my back up head was found to have some issues as well and we only had 4days untill our spring series started! so this is what i did i tore down my 07 250r ,took off the ported head and athena 280 kit which only had 7hrs on it.and bolted it down on the 04x bottom end .the carb has a quick shot installed .<on the 04 carb>. i was reading around here today and realized the 04 carb is a 37mm! and my 07 which i cant ride now anyway has a 40mm carb! would it help to put my 40mm carb on the bigbore< i assume this is a good idea>also will the cdi off the 07 be of benifit and will it just plug right in? also running stage 2 cam with the head. any input would be great.