hi my bike is 2 wheel drive model. the other day it just died suddenly while driving, has no spark, as i have two of these bikes i have changed all relays, coil, plug, ignition switch, and still no go, have tried towing it.

Only unusal thing is that i run both bikes without a battery and kick start it to get going. has worked fine and the other bike is still running like that.

not sure if these things have points or something similar.
could it be the alternator if so where is it?

any suggestions greatly appreciated