05 VRSC,Developed a stumble while riding at speeds about 30-40 mph. Also can here popping through the throttle bodies at highway speeds. Pull it up to 5000 rpm and it breaks up. Idles fine.Starts fine This was intermittent at first.But seems to be getting worse. No codes Drained the fuel tank, have 62psi fuel pressure,new plugs look good. Looking down the throttle bodies I can see a huge amount of carbon build up on 3 or the 4 valves.Lookes like the injector cleaner i've been using is breaking it up. Could I have pieces getting stuck on the face of the valves or within the seats? Or what else can I look for.