JS Motorsport
 
 
motorcycle
HIGH-PERFORMANCE
PARTS
FOR NORTON TWINS
JS Motorsport
4480 North Academy Avenue
Sanger, CA 93657
Phone/Fax: 559 875 0659
Email: jim@jsmotorsport.com
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 (page down for JS3 smoothramp).

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

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