You might try Matt @ Michigan Motorcycle Salvage
(586) 463-PART (7278)
295 Southbound Gratiot• Mt. Clemens, MI 48043
The kill switch is the only switch in the top half of that assembly,so it should be a pretty easy swap if your handy with a soldering iron. In most cases, these switches can be taken apart and cleaned. I've done two of them this week already. It's not that bad. But if you've got one that's broke, that's a different story.