porting isnt really that bad. you just have to be mindful of a couple things, especially concerning the exhaust port.
the exhaust port on motobecanes is that size for one reason -to limit power. raising the exhaust port will increase upper mid range to peak rpm power but will always take a chunk out of the low end, therefore i wouldnt advise rasing the exhasut port more than the 3mm or so that the artcile in the wiki suggests. however, you can also stand to widen the exhaust port a fair amount which will also increase the mid range to upper rpm power without sacrificing too much in the low end. as a general rule its not advised to make the exhaust port wider than 0.65-0.70 of the bore diameter (39mm). any wider and the rings will bulge out into the exhaust port too much and snag. when widening the exhaust port, its good to make the center of the top of the port 4-5 degrees higher than the ends. this will gently close the rings as the piston moves up in the bore and cut down on ring wear.
read 'two stroke performance turning' by A. Graham Bell (found here and that should help you out immensely.