Can a diamond chain cut rebar?

Yes, Number 4 or 5 (12 or 16 mm) bar is not a problem. Anything over number 8 (25 mm) is difficult. Large amounts of rebar will reduce chain life. Caution: Rebar or steel must be surrounded by concrete or aggregate material.

How long will a diamond chain last?

This depends on the material being cut, chain type, experience of the operator and how much rebar is present. For example, diamond chain on gas saws will typically cut 40 to 80 linear feet (12 to 24 meters) in 6-inch (15 cm) concrete. On hydraulic saws, this range is most often doubled.  
Diamond Chain Life Tipsheet (PDF)

How long does a guide bar last?

Normally two or three chains. Heavy rebar can shorten bar life

Can a concrete cutting chainsaw cut dry?

No. It is a wet cut system. 20 psi (1.5 bar) minimum is required.

Is "kickback" a safety problem?

No. Wood cutting chain has sharp hooked teeth that can grab the wood causing kickback. Diamond chain grinds through concrete with very small teeth (diamonds) without hooks. The preferred method of starting a cut is to plunge straight into the wall. There is no rotational kickback; however, firm footing and a two-handed grip is required and important for safety.

How fast will a concrete cutting chainsaw cut?

When does the chain need tightening?

Diamond chains tend to run better when slightly loose. It's normal for the drive-links to hang completely out of the bar. Tighten the chain when the drive-links hang more than 1/2 inch (12mm) below the bar. But remember, you should be able to pull the chain around the bar by hand, otherwise it is too tight.
Chain Tensioning Tipsheet (PDF)

What is the mixture ratio of oil to gas?

25 to 1 oil to gas mixture. Recommend customer use a separate
gas container marked: ICS 25:1. Use ICS formulated oil to provide maximum protection for the engine. ICS saws have a heavy duty cycle of up to 15 minutes of extended loading. 25 to 1 adds extra protection to your investment.