I had that problem too.
I bought a Suzuki FZ 50 last year and it was missing the ignition key. I pulled the thing off of it (carefully) and I took it to a locksmith. For eight dollars he was able to make a new key for me and I've had no problems with it.
Just make sure that you go to a professional locksmith, not some hardware store key copier who won't be able to help you.