WOO HOOO!!!!!
I love those old Can-Ams. I have a 400 MX6-B, about the last Open-class Canadian-made motocrosser. I also have the remains of a 175 Qualifier as parts, but the bike was so badly abused there was just about nothing left.
Check E-bay or the net for some leads and info in parts and service. Years ago, I knew of a couple of Canada Post employees in Oshawa, Ontario who had cornered the market on parts. I do not know if they are still into it, though.
As 2-strokes go, these bikes were pretty simple and straightforward. Anyone with 2-stroke dirtbike repair experience can figure out how to keep one running.
Factory-original parts are very difficult to find. But many parts, like fenders, cables, handlebars, tires/spokes/rims, drivechain, shocks, filters, lines, and most electrical parts can be adapted from other makes of bikes or from generic parts.
As a last resort, keep your eye open for other Can-Ams for sale. These bikes, especially broken ones go really cheap and would be good for parts..... even if you do not need the parts right now.