Well the Hornet from hornet has progressed but it still has an irritating issue. After some slower riding the temp will rise to about two notches from the top and the thermofan comes on. This isn't so much of an issue and is probably to be expected on a 30C day. However, when the bike gets this warm it starts running like poo. But only at low revs - taking off from a stop is particularly a problem. In many cases the bike will start moving then all power will disappear and it will stall. It also may stall at idle. At colder temperatures there is no apparent issue or at least nothing unusual for an ageing carby bike. I am now looking at the regulator/rectifier because I have had a few headlight globes and the thermofan fuse blow on a few occasions. My theory is that heat soak causes break down and the voltages at low revs are such that the ignition is too weak at low revs to run smoothly. Am I barking up the right tree?