I was in the motorcycle industry out there in Niagara for a long time, worked at Clares, had my own shop, raced, know many people out there, etc....
First, post an ad at the local shops: Clares especially and the other small ones over in st.kitts and stoney creek and down to JAG repairs in Niagara on the lake. Find Beaverdams racing website out in Niagara, the local guys might see something. Bike like that is likely still around Niagara, like someone above said it's likely local kids because an almost 20 year old dirt bike. It should not be high on the list of things to steal if you had any brains, not much point in risking a criminal record over. Back in 92 my GSXR 1100 was stolen from me 1 week after my mom died and it was not insured.....and I still owed money on the loan and it turned out to be a guy that had a blown up one that I knew in Welland. Most of the stuff stolen from my friends and I we found in the charming town of Welland! There's people out there that are a waste of good oxygen, luckily though they're not usually very articulate so they usually get caught sooner or later. Be cautious if you're ever selling stuff or when you've got the garage door open etc, if the wrong person sees your stuff, they just might come back, don't advertise.....like the guy who rolls around the neighbourhood with his new car stereo blaring and wonders why it's been stolen a week later. Another thing, buy some big cobra links type locks and use them. Hope you find your bike.