Strange sound when rolling off throttle and Akrapovic pipe
I've just bought a z650 and I've been using this forum for the past few weeks to get ideas for mods etc and I was hoping that you guys might be able to help.
I only just got the bike and I've noticed an unusual noise that sounds sort of like a quiet whistling or something (it's hard to describe) when engine braking (i.e. I've rolled off the throttle). I don't get the noise if I pull the clutch in and cruise but I do get it when engine braking. I installed an Akrapovic titanium racing pipe the day I got it so I never got the chance to see (hear) if this noise was present with the stock pipe, so I'm not sure if it's normal or not. Is this a noise that you guys have heard before?
Also, does anyone have the titanium racing pipe? It seems like the head of the allan bolt that holds the DB killer in place is spot welded. Any ideas of how to get it off so that I can remove the baffle..? It's hard to get to. I doubt I'll keep it out but I'd like to hear what it sounds like without the DB killer in.