Originally Posted by Krono
... what would gives almost the same gearing reduction but at the added cost of a new chain, as 13/42 allows you to keep the stock chain.
Another factor to consider is possible interference with the chain guide and/or chain guard when using 45T, or larger sprockets. Also, the larger sprockets might cause accelerated wear of the chain guide slipper, part #9 in the following diagram.
2005 XR650L: Shorai Battery Relocation, Spud Oil Cooler, XR650R C/S Sprocket, Reinforced Subframe, Chain Slipper Roller, Performance Design Lowering Link, Baja Designs Headlight, FMF Hi-Flo Header, ManRacks SD Rack, ManRacks Front Fender Farkle, CST Surge I Front Tire, D952 Rear Tire, Tusk D-Flex Handguards, Uni Air Filter, No-Toil Evolution air filter oil