Hypotheticaly......
Yes you can . if you can weld. you cut the can off at the weld where it connects to the down pipe, remove the baffle, or part of it, and weld the can back on.
BUT DON'T!
This WILL effect performance possably by leaving a big flat spot in the revs, so you may have to re jet the carburettor, change air filter, etc to improve performance. (which can be done in other ways like rebore or skimming or opening up exhaust port. besides this is not a sports bike :) )
ALSO........
If you intend to use it on the road......
The recent changes rumored to come up in an MOT is A decibel (NOISE) test so either keep an original to put on or dont do it at all.
Eab, February 2006