10-hp 100cc Four-stroke (number discs?)

[skooter]

I just purchased the 3M DirtBike [317-1000] with 4-stroke core kit and resonator. I will be re-jetting. What is the appropriate disc range for a 10-hp 100cc Four-stroke street-bike? What's your best guess on how many discs would be about 110 dBA? Also, I will be welding the exhaust to the pipe; should I weld first and then pack or is it fine to weld with the core kit installed?

Thanks (smile).