I have a 2004 Vstar 1100. I have Cobra drag pipes without baffles. I was originally experiencing back fire on decal like many others probably have. I eliminated the AIS and installed a Cobra stage 1 jet kit. I followed Cobra's instruction on what main jets to use in each cylinder and placement of the needles with my current exhaust configuration. Since rejetting my bike has had a loss of performance on the lower end. At idle, and up to half throttle, it is fine. But as soon as I get above half throttle I get spitting, sputtering, and backfire out of the bike. Any ideas???