Tuning for Specific Powerbands
Component: Cylinder Head
Low To Midrange: 9.5:1 compression ratio, squish band 60% of bore area
Midrange and High-Rpm: 8:1 compression ratio, 40% squish
Component: Cylinder Ports
Low To Midrange: Exhaust port 90 ATDC, transfer ports 118 ATDC
Midrange and High-Rpm: Exhaust port 84 ATDC, transfer ports 116 ATDC
Component: Reeds
Low To Midrange: Dual-stage or .4mm fiberglass petals.
Compromise: Thick carbon fiber petals
Midrange and High-Rpm: Large area 30-degree valve
Component: Carburetor
Low To Midrange: Smaller diameter or sleeved down carb (26mm for 80cc, 34mm for 125cc, 36mm 250cc)
Midrange and High-Rpm: Larger carb (28mm for 80cc, 38mm for 125cc, 39.5mm 250cc)
Component: Pipe
Low To Midrange: Fatty or Torque
Midrange and High-Rpm: Desert or Rpm
Component: Silencer or Spark arrestor
Low To Midrange: Short, small diameter
Midrange and High-Rpm: Long, large diameter
Component: Ignition Timing Advance timing
Low To Midrange: Stock timing
Midrange and High-Rpm: Retard timing
Component: Flywheel
Low To Midrange: Add weight
Compromise: Stock flywheel
Midrange and High-Rpm: PVL internal flywheel
Component: Fuel
Low To Midrange: Super unleaded 93 octane
Midrange and High-Rpm: Racing fuel 105 octane  |