Cams, simplified.

Sort of.

http://www.mikuni.com/pg_cam.html

[Hawkeye]

there was no mention of ramps on the cam's. These are there to make the bike quiet for most road use.
The old Triumphs use to have some pretty hairy cams that had next to no quietening ramps, this resulted in a bike that went fast but sounded like like a bag of nails, a big bag.

It was a good article though, found the bit about the closing of the inlet cam determining the RPM.

[S.T.Chapman]

this is also very useful

http://www.mikuni.com/fs-tuning_guide.html