Hi. Picked up an 09 KTM 300 exc the other day. Has not been ridden for 6 months, and fuel appears to have been left on. Starts OK, and runs well at high revs, but runs rough under load and when flattened off at stable speed. I suspect the premix oil has settled and gummed up the carby. is this a remove the carby job, or is there an additive I can place in the tank to assist?