Sorry, I didn't check this yesterday! I can still get it to you if you want, the thing's got an adamant nature and EV's in attack and hp. It's all fine if you're getting the other one tho, just lemme know.
I'm having this same problem. I found him standing outside of Craudburry's house at some point and talked to him. He responded like I'd just completed a mission and then disappeared, but I checked and he still wasn't in 7th Street.
Wondering if it's because a few events were missed in between? I already have the bike and I can't exactly remember what happened in the Magma quest line. Kinda at a loss for what to do.