I have checked every thing on this bike. The valves, coil, stater, been through the carb numerous times. What the problem is it takes for ever to start it will back fire when kicking then after a while it will start. When it is running i have to hold the throttle at 1/8throttle and it runs real rough it will stay running at this position but can not throttle up it will cough out and if you let idle it will die then it takes for ever to start again and some times it wont. I have spark every time i check and the carb bowel is full. I need help please.