NEVER run a chain saw without the bar and chain attached. Revving the saw without the cutting attachments could cause the clutch to disintegrate and possibly frag the operator or someone standing nearby.
I was reminded of this basic, though little-known, safety concern after velvetfoot posted a question about chain saw clutches.
On a related note, don't ever take a saw into a dealer for service without the bar and chain, since they won't run the saw without them either, and it's not very polite to expect them to scrounge up an appropriate bar and chain for your saw, just so they can set the RPMs.
I was reminded of this basic, though little-known, safety concern after velvetfoot posted a question about chain saw clutches.
On a related note, don't ever take a saw into a dealer for service without the bar and chain, since they won't run the saw without them either, and it's not very polite to expect them to scrounge up an appropriate bar and chain for your saw, just so they can set the RPMs.