jawas are awesome, but some parts may be a little hard to find, but not unobtainable by any means. if you just need some wiring, and no components, you should be fine. if you need things, such as a coil or thyristor, it is possible to find, so don't worry.
folks here will tell you jawas suck and parts are impossible to find, but don't believe them. those who say that don't know--they are not jawa owners.
no, it's not a puch or tomos, but if you look, you'll find what you need.
as far as carb, go dell'orto--cheap and more power. i'm now in the process of fine-tuning mine, and i like it thus far.