Today the delivery person brought me some goodies and so I fitted a new battery and a new rectifier.
Turns out you are all wrong, and so was I :-)
It was the damned fuel taps, they were dribbling like Dave going for a pee. So gave them a quick reverse blow and there was a little more flow. Took it up the road and woop the thing flies again. Thoughts are that when we opened the throttle they were preventing even the fuel in the carb from flowing as there was a blockage at the tank.
So I will run the fuel down a bit and then see if I have the confidence to remove the old taps to give the filters a clean and the tank a good flushing. That damned Ethanol.
The bike has an emergency mode and it will never happily run on it, it will start and ride but it is not great fun to ride. I was trying to start it in normal mode so it should have been just fine.
If you can reach it, while the engine is idling, remove the plug wire and see how far the spark will jump while idling. Using that as a gauge, slowly increase the revs and see if the spark fizzes out or begins to fire erratically.
Do I look that daft! That is a surefire way to get the output of the coil running via you. Next time you see a friend starting a bike, take the plug out, and then put it in the cap, ask them to try and start it and see how long you can hold on. My dad got a V8s worth at the weekend, he is still muttering about it now.
I had a 1972 Triumph Trident many years ago, and discovered that while it would run without the battery, it needed a decent-sized capacitor (I used a 2200uF electrolytic) in order to smooth out the pulsating DC current.
I think what happens as the revs start to rise, the pulses (with no battery to smooth them out) don’t allow the coils to work properly.
Try putting a big cap across the battery connections and give it a try.
I was thinking similar, but you would expect the rectified pulses from the alternator would always have the same phase relationship to the ignition points, so a pulse would be available while the points are closed and the coil is charging. Unless of course there is a mechanical advance mechanism on the points and as the engine speeds up it moves the points closed position too far away from the alternator DC pulse and so it begins to run badly?
This bike was the epitome of modern tech, gone was the manual advance and retard system that was good for giving you a broken ankle if left in advanced. It has a auto-advance/retard which is just some weights and some springs that as soon as the engine spins they move out. The next advance was electronic ignition but that came after this firm was out of action, which is a shame as the AJS/Matchless brand was the creator of the suspension systems most use today.
I had a 1972 Triumph Trident many years ago, and discovered that while it would run without the battery, it needed a decent-sized capacitor (I used a 2200uF electrolytic) in order to smooth out the pulsating DC current.
I think what happens as the revs start to rise, the pulses (with no battery to smooth them out) don’t allow the coils to work properly.
Try putting a big cap across the battery connections and give it a try.
I might still try this as the battery is ok but I did notice the rectifier isn't perfect and might help a little to have a bit of buffer.
Attached below is the wiring diagram I made up when I made the new loom. I upgraded the wire to 2mm² and added an extra positive earth from the headlight to the frame as it's 6V electrics so v-drop is always a worry and the use of the lights after dark is akin to using a candle. I was also a sad person for replacing the wire with the same colour markings as the original loom as I wanted the next owner to be able to read the manuals and make sense of the connections. Nothing worse than a vehicle wired up with just blue wire, how would you know which wire to cut?
EDIT: It is a single-phase stator.
