That's very vague. Is it on acceleration from a stop? At idle? Or at all times? When was the last time you removed the side cover to clean the inside of the case, clutch and variator? With the side cover off it might be easier to pinpoint the squeal.
Here is a link to a thread about glazed clutch shoes causing a squeal on acceleration and remedy.
I have an idea, have a refreshing beverage and search "burgman howl" see if it's the same, then, go out and get us a recording, and more info like Fester suggested, also, check on the whereabouts of the cat
A forum community dedicated to Suzuki Burgman motorcycle owners and enthusiasts. Come join the discussion about performance, modifications, classifieds, troubleshooting, maintenance, and more! Open to all 200, 400, and 650 models!