Dear Andy!
Is it really the NOISE, or the SOUND you want to improve?!?!
I have listened to Harleys that were just LOUD, no good sound at all…
I reckon you hardly get a better noise than a fine and sorted out Commando that is being accelerated from standing start. The sound from those peashooters is just amazing and I am glad my Commando 750 S does not bring out too much noise.
The peashooters were originally designed for the bike, giving it the perfect power-to-sound balance as well (Thanx Wolff Olins!!). Anything else is a bad compromise, in my eyes.
If you want the real grumpy, unadolescent, filthy sound, go and buy yourself a Norton 500cc longstroke Manx. THAT must be like the bells of hells. Sets you back top $$$$, though, but must be one of life’s greatest joys.
Easiest solution: revv your Commando 4000–5000 rpm while you are not wearing a helmet, and it sounds perfect.
That is me being a typical German smart-ass…
Regards from Hamburg, Germany
Matt