Smoke from water, oil, or gas. Water is from condisation in exhaust when drain holes in exhaust get plugged. Exhaust then collects water. When water finally "boils off" then smoke ends. Black-ish smoke is unburned fuel showing need for carburator cleaning and possibly adjustment. White smoke is from oil getting combusted due to poor valves and or rings. It will feel oily unlike water smoke. If bike has been sitting for months, some smoke is expected until it is ridden for a while.