Measuring RPM's. What tachometer is needed?

[AustinS]

Can I use a digital tachometer or what? How do you measure the RPM's to make sure the idle is set correctly.

I found a pretty neat little tach that might work but I figured I would ask before blowing $40.

http://www.tinytach.com/tinytach/gasoline.php

anything cheaper that would do the trick? The one abvoe wraps around the sparkplug cable. How do the laser tach's work? I guess it wouldn't really work on a scooter unless you could take the fan cover off.

[Kenny_McCormic]

You dont need a tach to set the idle.