I say for ignition they should just put a little spike on the piston and then have a mechanism that feeds in a series of percussion caps, like they use to fire the gunpowder in ammo cartridges, particularly for the four-strokes. Looks bad-ass, gives the manufacturers more moving parts to replace and make money on, and you can put a "450 Magnum" sticker on your bike and tell your friends about how much power you have now. And the best part is, you can just remove the normal ignition system from your bike, which you don't want anyway because it works using quantum gibberish and magic, and that sounds scary.
Honestly though, when I saw the title of this thread I thought it would be about a device that does the opposite of a spark arrestor.