I have an LT80. I bought it used, not sure of year, i think early 90's. I have fmf fatty exhaust, with power core 2 silencer, boyesen reeds, uni filter, moved the needle clip all the way up to to the top, have the throttle and exhaust restrictions taken out, and put in a 90 jet. the quad is nice and jumpy off idle, but right as soon as power ban is about to kick, the engine stumbles, and pops, back-fires, spits, and will not go any faster. it has done this since i got it. i took off the carb, cleaned it extremely well, no dirt or gunk anywhere on or in it. i was reading about this happening to other people, and they say they had to drill out the floats in the bowl to allow it to fill up faster. if this is what i need to do, can someone point me in the right direction on how to do it?? any other tips or help to get it running right would be awesome. thanks.