It likely doesn't work because the modem only allows you a single IP address and when you bridge you have multiple devices trying to use it.
You are going to have to use something like ICS to make this work. It tends to be even more tricky when you put a second router behind the ICS, you will likely get better results using it as a AP.
I would consider a router that supports you directly connecting a 3g/4g modem. Asus and tplink have a number of models but you have to look though the list. Since most hits I get on Yota modems do not come up in english I can not be of a lot of help. I don't think asus or tplink support it but there are a number of other vendors. things to search for is 3g/4g broadband router.