As others have said, there is no rule in negotiating. You decide how badly you want the bike. Sit down and figure out the most can actually pay for the bike, and verify insurance cost BEFORE you purchase the bike. You also need to allow for gear in the first year. You can then go in person to the dealers that you can get to easily (like don't drive to Peterborough are if you live in Oakville), and negotiate the best price. Be prepared to get up and walk out if they will not budge. Do not show any emotion, like getting all excited at the prospect of getting a new bike that day.
They need you a lot more than you need them. Do not get aggressive, or angry or upset by the price they offer. Always negotiate the out the door price from the beggining. All you need to be aware of is the final out the door price. For example, one dealer tells you $5100 for the bike, and another dealer tells you $4800. The first place may have an additional $200 for misc fees, and license plates, plus HST. The second will have additional expenses as well, but they are $500 plus HST. There is no standard price for the misc prices, the freight may even be different between two dealerships. If you only deal with out the door price, it gets around this extra charge crap. Remember, dealerships will not pricematch the misc charges. They may price match the actual bike, but, the misc charges is where the most profit is.