I have a yx 150cc had it for about 8 months hasn't ran right since after the fist 3 months after I got it it has a pissy 22mm carb stock it started fine and was alright at idle but as the revs got up it started to back fire and pop and the throttle respoce wasn't there and was bogging out ive checked for all air leaks exhaust it tight cant figure out what the problem is im buying a oko soon as I have enough coin just wanting to see what u guy's thought it could be a mate suggested the valve clearence could be out but im no mechanic it has totally got me stumped any info or advise would be of agreat help