Motorcycle or Moped

Hello. I want to purchase some transportation. Not interested in a car as I will not be in Niamey for too long. Just looking for a motorcycle or moped. Can anyone please tell me where motorbike shops in Niamey are located. What should I tell the taxi driver? Thank you for any other assistance or advice. Please feel free to reply to my email also: areyouavailable@hotmail.com. Thank you.