Logarithmic scales.
How i hated you at high school
Redusing induction noise alone will knock off a couple decibels. Get your self a factory airbox with lid, and drill some holes in it. This will be heaps quieter than open carbs.
The factory pipes are double skinned, and while being heavy, are pretty quiet in terms of resonance produced.
Mufflers will be your only gripe.
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