Conventional Norton race cams have abrupt ramps that can cause valve bounce at high RPM. We put that right by modifying the ramps so they are more gradual for higher RPM capability and reduced wear on valve train. All JS cams have asymmetrical smooth ramps to avoid valve bounce. The illustration below compares the PW3 profile and ramps with the upgraded JS2. Note the asymmetrical shape with a longer more gradual closing ramp.
The JS3 smooth ramp cam below is compared with the famous D+ grind (Sifton 460) and shows the improved ramps for eliminating valve bounce. Note the asymmetrical shape with a longer more gradual closing ramp.
The dyno chart below shows a 500cc short stroke with a JS2 smooth ramp cam & beehive springs being revved to 9000+ RPM. The blue line was after the timing was corrected.