In episode 18 of Gundam Build Fighter Try, the music starts from 12:44 (maybe? I'm not sure, correct me if I'm wrong) to 14:46.
I've been searching the whole YouTube, internet, and SoundCloud but won't get an easy hand on it.
Somehow, Sunrise like to use the old OST from GBF to GBFT, so I assume it's an old OST from GBF instead of GBFT (cause I have a full set of GBFT OST)
Here is the link to the episode on the official Gundam channel.