Right today, went riding, bikes fine for about hour or so.  Tyres felt abit flat so went to pump them up.  Come back, bike starts to make a funny clunk noise, not always a noise but can feel something when pedalling.  So I checked cranks, no movement sideways, not lose etc, did them up to make sure, checked pedals, checked rear wheel, checked mech nothing seems lose.  BB isnt wobbling either.  So I get back on, its still happening, now I pedal softly, ie putting weight on bars and enough force to move wheel and no feeling/noise, I pedal normally feeling and noise are back.  It generally seems to be when the left crank is returning to an upwars position ie 12 o clock.  Anyone got any ideas its all new stuff 2 days old or so, echo bb, echo cranks, gu bash, surely cog, wellgo pedals with pro 2 hub.