I have a 05 CRF 100. It has been sitting for 2 or 3 years. But was running fine before that. Now it starts fine but won't idle or rev out unless it is set at half choke. I have pulled the carb apart and cleaned it, also replaced the jets. Have also had a bike shop look at the carb and clean it, seemed okay. The fuel line and filter seem clear as is the air box. Replaced the plug, spark seems good. Any ideas?