There are so many Ramen shop in Jakarta in these days.
Bankara, Menya-Sakura, Ippu-do, Santoka and etc., these are famous Ramen shop in Tokyo and they have opened their branch in Jakarta.
Personally I think Santoka is best in Jakarta, that is my recommendation. But that shop is in Plaza Indonesia where is a bit far from my house. So I often go to Bankara which is in the closest shopping mall, 10 minutes walk from my home.