Firearms can be taken into Canada, including pistols. The problem with taking a firearm into Canada is that they have too many laws (as far as I'm concerned) that you could violate. To start with, you have to make sure the firearm you want to bring is legal in Canada, and the rules probably vary between provinces (and territories) like they do between our states. There is paperwork that you have to have when arriving at the border and, from what I have read, it needs to be filled out before you get to the border crossing except for the signature... so they can witness you signing it. If you really want to take a firearm with you, contact the Canadian government first and verify that your firearm is legal, where the rules and forms are on their website and it would also be a good idea to have them mail you any literature they have on the subject. I would also contact the Canadian border crossing where you plan to enter Canada to verify with them what their interpretation of the law is and how it applies to what you plan to bring (and get the name of who you talk to). I have seen, and heard of, too many instances when some member of law enforcement 'knew' what the law was, but in reality didn't. I wouldn't want to be sitting in lock-up while they get it straightened out. I would also check with the U.S. border crossing where you plan to re-enter the U.S. just to make sure you don't have any problems there either. I carry almost everywhere I go, but when I'm heading to Canada I just don't feel like going through the hassle. Two good places to start would be:
http://www.cbsa-asfc.gc.ca/travel-voyage/rpg-mrp-eng.html
http://www.cbsa-asfc.gc.ca/publications/pub/bsf5044-eng.html
If you really want to have a 'gun', flare guns are legal in Canada. Most criminals would rather be shot with a firearm than with a flare gun. I don't know, however, what the laws are as to how or where you can or can't carry them but they should be OK anytime you are on your motorcycle.
You can have 'bear spray' or similar items, which are fairly large, as long as it is labeled as being intended for protection against animals. Pepper spray, mace or anything similar that is for self defense against people, or not labeled to be used against animals, is illegal. Some cans of bear spray come with a holster that hangs from your belt. You could also attach some sort of cup holder to your bike to carry your bear spray and some sort of a coozie (or koozie, depending on where you're from) to keep it snug in the cup holder so it doesn't bounce out. One thing about bears... When startled they take off in the direction they are facing. If they are facing the road, they will run out in the road in front of you.
Canada doesn't have any restrictions, that I'm aware of, on the size knives. I have one that even Crocodile Dundee would probably say "that's a knife". The border crossing people looked at it and went on looking through my stuff. They do, however, have restrictions on things like switchblades.
If you want to have something for defense against people or animals, a can of Lysol, or hair spray, and a Bic lighter can be awesome and normally aren't categorized as weapons..
When you get to the border crossing, declare ANYTHING AND EVERYTHING that is considered a weapon, including bear spray, knives and flare guns.