Carbon frames are quite common these days but too often damage is incurred rapidly when a part is tightened beyond specifications or crash damage is not investigated promptly. Especially when working on a bike at home, a few precautions will prevent much potential difficulty.
The most common error when dealing with carbon bikes or parts involves torque. If fasteners are not evenly tightened or are too tight, damage to parts can result. Carbon bars can be crushed if the recommended torque is exceeded on stem faceplate bolts or other pinch bolts. Anywhere a carbon part is clamped, whether it is a seatpost, handlebar or for steerer tube, overtightening fasteners is a concern. Many manufacturers include a printed torque specification on their products at this point. The simplest way to avoide damaging parts is by purchasing a torque wrench. A torque wrench allows the user to check how tight a given fastener is. A simple version of this tool is available preset to 5nm and this value will cover stem bolts as well as many seatpost binder bolts. An adjustable, shop quality model is available as well. It can be set to register 3-17nm torque values.
Another aspect of carbon frames and parts is that they require non-petroleum grease. Anywhere the grease contacts a carbon part, using a non-petroleum based grease will preserve the integrity of the carbon it is applied to. Petroleum based products cause carbon to deteriorate and weaken over time. It will not necessarily be visible but eventually it could result in damage to the bike or to you. One great option for carbon compatible grease is made by Finish Line.
If a seatpost has a tendency to slip in a carbon frame or if the post is carbon and the same symptom is noted, a particular grease is available to correct this inconvenience. This grease includes added particulate for greater friction.
Many modern carbon frames incorporate a semi-integrated headset. This means that the cartridge bearings of the steering assembly occupy a pocket in the frame. Often a thin metal sheath is incorporated into the frame to accept the bearings although sometimes the bearings directly contact the carbon frame. If the headset adjustment is loose and the bicycle is ridden in that condition for several rides, the carbon surface where those bearings sit will be abraded by the cartridge bearings slipping around under load. Eventually the wear will become severe enough that the frame is compromised. A damaged carbon frame can sometimes be repaired. Depending on the damage and its severity, the frame may repairable. Some frame builders are capable of performing this repair.
In the event of a crash or significant impact, bring the bike to a shop for inspection. Damage to carbon frames and parts is often less visible than on metal parts. A compromised frame or part can take weeks or months to fail. If this happens at a moment of great speed the result can be mighty unpleasant.
That is enough caution for one article. Enjoy your bike, check its fasteners periodically and enjoy the ride.