Moto g 4g XT1040 ( can not get root accesos)

Hi, please I would like to install a ROM in my moto g 4g xt1040. Once I tried to install slim kat and it worked good. I used twrp recovery with my device rooted to flash slimkat ROM... Then I notice that there was a ROM , cyanogen mod 12, and I tried to flash it as I did with slimkat. But I did something wrong :( because it booted normal, but the screen was flickering, and I had no signal. So I had to get back to stock ROM. I restore a stock rom i found here in moto g 4g section, then I installed twrp recovery again, but I could not root my phone anymore, there was a message ( root missing , do you wish to install root , or you will lose root. I tried to install cwm recovery , but it was the same. I think that the stock ROM I flashed to restore my phone is not okay. I can not flash any other ROM anymore.
Someone can help me please. Maybe I am doing something wrong. If someone need more information, just ask me.
Thanks a lot ( sorry for my english)( new a world of rooms)

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