You can buy carbon fiber cloth (I believe you'd need 2x2 weave or 'bidirectional', NOT monofiliment or unidirectional) on ebay, Aircraft Spruce, and a bunch of other places. You'll need either fiberglass resin, or better yet epoxy resin (aka two-part epoxy). The HARD part is to successfully hand-lay the material though. Making moulds using silicone, plaster, or other materials is a tricky process to get right, and finishing the CF is a LOT of work.
If you're not an artist or a skilled automotive bodywork person, I wouldn't waste the time and money. Paying $60 for a chain guard or $100 for rad cowls is a lot cheaper than multiple screw-ups.
If you're REALLY interested though, I'll try and get a how-to photo/text process posted up when my father and I rip into making parts. After I get some pulled I'm going to invest in the quality silicone for making professional moulds ($150 a gallon jug) and maybe make a full run of carbon fiber headlight fairings and misc. other bits.