JS Motorsport Technical
JS2 & JS3 smooth ramp cams

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. The illustration below compares the PW3 profile and ramps with the upgraded JS2.

JS2 meg & Smooth compared for web only (sized)

For ease of viewing, the image below has the profiles re-aligned so both ramps begin at the same place. You can clearly see that the improved JS ramp is more gradual that conventional Norton cams.

JS smooth compared for web only (sized)

The JS3 smooth ramp cam below is compared with the famous D+ grind (Sifton 460) and shows the improved ramps for eliminating valve bounce.

JS3 web & Smooth compared for web only (sized)

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.

Rodger M 500 102020180 httpgdurl.comsw4 9