^
I use
this one. It's almost exactly the same size as a 540 size motor, and works perfectly with the Tekno 36mm motor mount. I just had to drill a hole near the front for the wires to exit...if I need to take it out of the mount again, I will drill more holes for ventilation. It's not a very powerful or extreme setup (running on a
6s 2650mah 20C lipo just fine) but it works well, and makes the 30krpm recommended lower limit.
What timing were you using? I heard outrunners like high timing regardless of what they're in, didn't know they reacted so poorly to bad settings.