How to wire a three phase bridge rectifier
The answer depends somewhat on what you intend with the AC and DC voltages afterwards, but one option is to ignore the Neutral line if you only want the DC output:

 

It would appear you have a 'Y' wired stator, so (if all you want is the DC output) you can safely ignore the Neutral.

All three phases are active all the time in a conventional generator. In your variant (which looks to be based on a washing machine motor) it depends on the configuration of the rotor magnets and stator coils.  

I assume you are have already read things like this.

Additional:   I'm not sure what you may have done with your motor windings, there are many projects where they are re-configured to get different voltage/current options. The table  below shows the options tried at this Uni for different applications. In many cases the voltage  output for the (usually with series connected pole windings) motor is too high at gas engine speeds so they get wired in parallel to reduce the voltage and increase the current capability.



I'd be tempted (and this is just my opinion) to wire the motor (series pole windings) as a Delta output configuration which will reduce the voltage ( this would reduce the voltage by (Y-phase-to-phase / 1.7) ) and increase the current capability (reduced phase to phase winding resistance) when gas engine driven.
And since the pole windings are stationary you could always bring them out individually and connect them into various configurations to test out your available voltage/current options at engine speed.