Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
You checked the throttle stop screw on the butterfly? it's an eccentric cam arrangement and if it's out it will hold the throttle open even with no cables attached.
What a momentous day, today, has been in the saga of my 500/4. I feel a huge corner has been turned, a momentous mile stone reached and many more similar metaphors you can think of.The bad running of my bike continued, so bad it was unridable. I didn't have the time it needed to sort it properly, but whilst working away, I continued researching my symptoms, and found an article about powering the coils straight off the battery, bypassing the ignition switch and the cut off switch. I also downloaded a copy of the electronic ignition system that had been installed on the bike a few years ago, shortly after I'd bought it. I set to this morning and made up my bypass lead. As I looked at the coils and the wiring diagram to work out where to connect to, I noticed that my coils were wired in parallel and they should be in series. I rewired them, as per the manufacturer of the electronic ignition systems diagram, and hey presto, a transformation occurred. The engine fires first time, every time on the button. The engine ticks over smoothly now and revs freely. I am over the moon.It still needs some fine tuning but for the first time in three years I am out and about on it with a huge degree of enjoyment. Thank you to all who have commented and offered advice along the way, much appreciated.
Boyer ignition?