For about $100 US, Max Torque will supply you with one. The internals are slightly different that their 4 stroke versions with some different fiber washers, and springs. I have one on both my 580 and A400. You can contact Jim Donovan directly on these via email.
I am not sure of the issues involved with shipping to Canada with respect to cost.
I was considering swapping out the 580 MT clutch for a #35 sprocket, then going traditional clutch on the JS with a band brake, but I am just not there yet. If you are using a JS, that is a consideration.
Direct Drive 9/16 sprocket.