New to this

Welcome Scott. You've come to the right place for answers.

As far as sprocket size (diameter & tooth count) it will depend on what engine you plane to install. Typically speaking if you're looking at the Chinese 2 stroke you'll want to go a little larger sprocket than what usually comes with the kits. Think of sprocket size as gears in a transmission. The larger the sprocket, the lower the gear. 44T sprockets are somewhere in the middle of the road, 48t is a little lower gear and then you can go crazy with a 56T or larger but don't expect too much in the way of top end speed.

Guys who are looking for speed will go down to a 36T and in some casese 32 or even 28. They have to pedal like crazy to get moving but their top end is good and engine RPMs are low.

You can check out the "laws & Legislation" section for answers about legalities in your area.

Like Silverbear suggested, start reading and see what is available in the way of powerplants for your bike.
Above all, have fun and ride safe.

Tom

Scott,
You're asking about the dreaded 'white wire'. There is page after page of discussion on that subject. Just type in 'white wire' in the search feature.

Many of us won't have anything to do with it. I snip mine off of every new engine and never look back.
The magneto is supposed to produce a 6 volt current to the white wire but that voltage varies with engine rpm. I've seen as low as 4 volt and as high as 10. The problem is that it is very low wattage. Using any incandescant lamp over about 2.5 to 3 watt will result in the magneto being unable to produce sufficient voltage to the ignition circuit.

There has been some experimentation with LEDs which have a lower wattage requirement but even then the amount of light available is not enough for real world night riding. I prefer to carry a small SLA (sealed lead acid) 12 volt battery to power my lighting and recharge after an evening ride.

Again, try the search feature and sit back because you're going to find plenty to read about the "white wire"

Tom