Hey just picked up an 84 vf700. from original owner, was garaged, nice looking bike. Well here's the problem, it runs, then it doesn't, no spark. I rode it yesterday around the neighborhood a bit, then shut it down to get a warmer jacket on to take it to the beach, and then no start, no spark. What's the most likely cause of this on these bikes. i know my cb550 is easy, points and coils, that's it, but this bike has much more to it.
There are two ignition boxes in the tail section at the rear light. Make sure all the contacts in the connectors are clean. Possible bad/dirty contacts kill switch/start buttons and or their connector up front. Try these first and see what happens. There is a silicone rectifier in the wiring hardness close to the coils along the right side of the frame. I have heard if that's bad bike won't start. I don't know what the symptoms are when it does go bad. I've also never had one go bad.
Dija check the resistance of the pulse generator coils ?? They might be OK when cool but fail when engine reaches operating temp. The part Grey mentions is the diode in the ignition circuit that won't allow the starter to crank if bike is in gear and clutch engaged; if it went bad (usually a result of battery terminal mixup) you should still be able to start if bike is in neutral and you squeeze clutch lever.
