Smoke coming out of the egsoust mini baja bike changed the oil put to much in figured that out.took some out put fresh oil in the right amount in runs fine for a minute then it starts smoking?

You may have blow a seal. This would cause oil to enter the combustion cylinder and cause blue smoke. Or the over fill could have cause oil to get in there and it will not smoke until it reaches the flash point (the point in wich it berns).