chain rubbing...

the chain on my bike is constantly rubbing the left side chain guide plate. like the chain is not centered on the middle of the 2 plates. any way to solve the problem? should i take apart the whole crankset and the chain guide and reinstall it properly again?
thanks

Are you talking about the chain rubbing the shifter guide, or something else? If it's the shifter guide, you'll probably be able to fix it by just adjusting the shifter cable. My Trek 4300 just came up with the same problem, but luckily, the shop I bought my bike from gave me coupons for free tune-ups, and minor repairs, so I'll probably have them do it.
Hope this helped you out somewhat!