Just a reminder of a topic that I,m sure has been covered a number of times.
As my 500 has become increasingly difficult to start over the last few months, I thought to get on with something useful yesterday I would investigate. It is fitted with Piranha ignition (remember them) that I originally bought for a Guzzi and then transferred to a Z650.
The spark looked OK, but when measuring the voltage at the coils it was nearly a volt down. A quick root around the shed revealed an old relay bought for some extra lights fitted to something years ago. Wiring this to switch power direct to the ignition system has made all the difference. Starts on the button.