gosh no, don't battery power it or that'll be the end of it being an ac system. Just about bet that it'll be the charge coil [heat & vibration kills them], the rest is very reliable. In my experience 300 ohms resistance for the charge coil which is the [thinking back] 'black with a red tracer' to earth with your multi tester 300 or a bit more but not much less. Then--if you have a "peak" volt meter & kicking it over you need around 160 "peak" volts, less than 100 & might still push start. If you only have an ordinary volt meter it should show half 'AC' volts ie 80 or so. This is with it disconnected & spinning via the kick start--plug out to make it easier etc. See how ya go & others might have different ideas but good luck--love those old motors & have a few. One in a PE250 frame for the last 20+ years. It's been hotted up--blown up--rebuilt with left over bits. By memory it's [not used it for a couple of years] a smokey 185 at the mo but had a 12to1 piston, megacycle cam & big carb [off a ts400]. Somewhere i've got a damn quick motor [revs like hell] in an xl185 frame using a 200 cylinder & 125 crank--that's where my megacycle cam went come to think of it [been trying to think. Could go on [& on] so better stop. Cheers.