TOPIC:

Would be interested in hearing what you all thought of that repro airbox silencer for the KZ900 that guy on Ebay is selling for $147. This is the one single part my bike is missing to make it completely stock. Couple things.. what exactly does the silencer do? I kind of like the sound my bike has now. How will the silencer change that? Also.. does the presence or absence of this part have any effect on the jetting? And...opinion... does having a repro silencer add any value to a bike beyond simply not having one?

When you open throttle on 73-75 z1 there is a roar as air rushes through air cleaner and carbs.
The air cleaner was redesigned in 76 to eliminate the roar and make the bike more "civilized".

And likely to make the noise police in Kalifornia happy.