Other aspect of quantitative analysis that's incomplete is with carb-tuning. We should be aware that new-gen bikes are VERY different from pre-gen bikes. Engines are tuned completely differently with different cams-profiles, head/port shapes, valves, exhausts, ignition-maps and of course, carburetor configurations. This entirely affects characteristics of engine and power-output
pre-gen 1988-2007
new-gen 2008-2012 - from Motorcyclist comparing with other small bikes
And dyno-chart comparing them, roughly ~6% difference.
Pre-gen vs. New-gen summary
5.75s vs
6.90s - 0-60 time
14.59s vs
15.30s - 1/4-mile time
87.82s vs
84.15mph - 1/4-mile speed
Performance figures between them also roughly reflect power-differences, although lighter pre-gen takes bigger lead from stand-still.. Riding them back-to-back, I can feel differences in power-output, but barely. For butt-dyno to really distinguish, you need at least 10% variation.
That ~6% power-difference is part of
carb tuning configuration from factory. Which should be used as baseline for all mods and adjustments:
Pre-gens = 105 main jets
New-gens = 98 main jets
Roughly same ~6% difference repeats itself. Be very, very aware when you are talking about jetting changes, which model you're dealing with. Pre-gen or New-gen; what works for one will not work for other!