View Full Version : 10-hp 100cc Four-stroke (number discs?)

02-06-2009, 12:12 PM
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).

02-06-2009, 02:50 PM
Depending on what you're end goal is, you may want to add/subtract discs and see what gives you exactly what you're looking for. A customer of ours is running the 3M Steel Dirtbike pipe on his 125cc '73 Honda XL and he's running 18 discs and said people can hear him arriving from a mile away.

Remember, adding discs will increase your horsepower, exhaust tone and flow. Removing discs will reduce the sound and increase your low-end torque.

You'll want to weld first and then put the core in it.

Good luck!!!

02-06-2009, 03:41 PM
Street bike. Looking for a general range when riding on the street without being too obnoxiously loud. Does 8 to 12 discs for a small-displacement four-stroke sound right? I just want to be in the ball-park before I start messing with jets.

02-06-2009, 04:08 PM
I understand. That would probably be a good start.