MongoDb Multi-Region Sharded

Hi, i got some latency issue with a multi region setup. Is working really good in EU, but got lot of latency in ASIA (XHR 60ms in EU, 400ms in asia for the same XHR).

My setup is :

3 config servers (primary in EU, secondary ASIA, secondary EU)
2 routers (EU and ASIA)
2 Shards :
RS0 : primary EU (electable), secondary EU (electable), secondary ASIA (read only)
RS1: primary ASIA (electable), secondary ASIA (electable), secondary EU (read only)

When im in EU, i got 60ms for my XHR, when im in asia, i got 400ms.
I tried to do a standalone mongodb just for be sure there is no problem with my server in asia, and then i got back my 60ms for XHR, so the problem is in my setup/configuration of mongodb.

I guess all the problem is because collection who are not sharded are keep in the RS0 and when im in ASIA, mongodb dont read the RS0 Asia but still read on the primary EU or secondary EU.

DId someone got some tips or know where is the problem ? Thank you so much