Didn't mean to dismiss you Mat, I was just being a smart ass since I had a good idea what the issue was (got a call from the service department).
Thanks to everyone for all the help and the ideas. I have to say that all the input was excellent and offered very rational and efficient trouble shooting procedures.
Got the bike back today and the problem was an intermittent electrical contact between the coil and the spark-plug wire.
I guess every time I pulled the plug and checked for spark or tested the coil the movement reinstated the contact making everything seem fine and run temporarily.
Once reassembled and ridden the bike vibrations or the position of the spark-plug wire broke the contact and killed the bike.
No wonder I could not find it and it drove me crazy. Hopefully this is the end of it. I have not had a chance to do a full test ride since it started raining right as I got home w/ the bike. (Note: It has not rained in 4-5 weeks!)
Now back to the regular scheduled programing.
Been following your saga, I own a '08 510, i am having the hot start issue,
as you discovered in your story,
the hot starting issue was the ignition lead and cap ? and this cured your problem?
I have over the years had a few problems, none ever stranding me, but that was more luck than design,
Coil terminals coming loose,
Relays rubbing through case and getting contaminated (pump relay)
Fan siezing
connectors behind headlight corroding
fuses getting micro cracks (look ok but cracked when looking closely)
lower link bearings seizing up in real wet weather (we had 600 mm / 2400 pts her last year) even after 2 grease sessions for the year.
Replaced the OEM fuel pump, but the original is still OK
rerouted rear brake line so it doesn't rub hole in case
fitted PCV and AT (thanks Scott @ Semco for help, because i was a bit slow on the uptake), fixed the flame out, it does change idle characteristics, i found that winding idle screw in to adjust idle level just made idle rough, screw out until idle is smooth, it settled at 1600/1650, low but it idles smooth and transitions fine, does have bring some heavy compression braking in some situations , but i can live with that.
Fitted a bum tank, works fine,
14 / 48 gearing