Did you test spark? If a plug grounded to the block won't light when pulled over, it's either a junk plug, bad coil, bad CDI, bad stator, or a wiring issue (black wire is grounded somewhere--brown is ground--black is kill).
When my coil went out, one plug fired while the other did not, so it still ran. I barrowed the coil off a friends sled (same on 600s, 700s, 800s--pretty generic part really) and my sled ran great the next ride. So I ordered a new one and went on my way.
Buddies stator went out. First I put my coil on his sled: no spark. Next I swapped my CDI to his sled: no spark. Then I found the resistance specs for the stator somewhere on this forum and test it: failed test. When I tested the wires coming off the stator there was one set that was open circuited when it should have had some resistance. Bought a used stator off the forum and the sled ran great again. I don't have the stator wire resistance specs handy or I'd post them for you.
I'm fairly certain there are two circuits on the stator; one for spark/engine and the other for lights/grip heaters/auxillary.