Why is it not flaming?

[Ruan]

Normally never flame/bang/fart unless provoked by cracking the throttle at around 4-6k RPM on the overrun. The management is calibrated well enough that it doesn't really do that, sometimes you'll get a very slight whiff of flame/black smoke when lifting off at high RPM, but usually not.

If it did before, it's likely it had an air leak on the inlet side causing it.