just having a look at one on the net now and your talking about the FASTACE BS-66RC-280L right?
i havent got one or umm really handled one so if you disregard everything i say now i wont be offended but yes just by looking at it i would be queit comfortable buying one for my fiddy, also what kind of bike do you have? im guessing maybe not a stock crf50?
but yeh from what i see i highly dout you would have any trouble fitting it unless you put it in upside down dw its been done LOL funny story or something like that but i reackon youll be fine!