I am so sorry that you can not drive your motorcycle in Sumatra, Indonesia. I am Indonesian but I just knew that foreigners are not allowed to drive their motorcycles in Indonesia, except in Bali. You had only one day in Dumai, Riau Province. I hope you had a wonderful day there. I hope this trip to Indonesia doesn't make you disappointed to go to Indonesia again. By the way, I live in Medan, North Sumatra Province.