I used a Model Factory Hiro chain kit, it's the easiest to assemble. Pre-cut PE plates and plastic sprue links that you solder to assemble. You get enough chain to do about 2 kits (if you are careful with your measurements and don't have to chop off excess length), almost 9 inches in total. I paid 17$ from StradaSportsStore.com (highly recommended, excellent source of motorcycle and automotive kits and detail parts, reasonable and prompt shipping). 
Other detail bits:
Dexter Models Senna transkit (with PE and resin details)
Dexter Models tire valve stems
Studio 27 carbon fibre decal sheet (not the best, stiff and very poor adhesion)
Top Studio 0.5mm rivets
Top Studio exhaust springs
Top Studio electrical connector kit (resin connectors with miniature insulated wire and shrink tubing)
MFH chain kit, comes with white metal sprockets for Tamiya's Moto GP bikes which I modified to fit this build