I shave down my old tires to about 1/2 inch then put ice screws in every knob, as many as will fit. Rember to rejet for winter temp. (ice screws at riverside in st. albert)
as carbs get older, they wear out the needle and run rich, I would replace all the jets and the needle with new ones of the same size. If the motor has not been rebuilt in a year or two, it is time for a new piston and ring(s). If it starts cold without the choke, you are definately running too...
This is a little north of Alberta but, I'm new to Yellowknife and it is a bit early, just triing to find info about riding areas around Yellowknife. Motocross track would be nice but not looking good, settle for an area that a track of sorts could be set up for summer.