Here's an update after spending a few hours tinkering this morning. I rechecked the carb and made sure every oriface was clear again with carb cleaner and compressed air, it is with out a doubt all clear.
Latest of the symptoms: While riding the bike for almost a couple of minutes everything is fine, full throttle no problem....then at a stop, gradually the idle started to get lower and lower until she died. Tried to fire back up, turns over, fires up but not long enough to stay running. Let it rest for about 2 minutes, fired up and rode it back home and then sure enough at a stop the idle got gradually lower until it stopped.
Put it on the lift and went through the same routine with it stationary on it's stand and ran it untill it petered out. Imediatly checked for spark which it has. Checked for siezure, turns over fine and compression still good. Drained carb, fine, plenty of gas. Tried again with choke wires disconected, no change.
I've seen this symptom before on other scooters which turned out to be a break down of the ignition coil or cdi when hot, however I've replaced both the coil and cdi and unplugged green wire with no change. Although it does have spark, the plug is now a very dark brown color but not oily or fouled. I'm not sure If the spark is breaking down at higher load / rpms. Does anyone agree that it could be stator/ignition pickup related ?
On a side note, the main is a 75 so I will certainly get an 85 and change it out along with leaving the green wire on cdi disconnected which I'm sure will increase performance although my gut feeling is that this won't cure the initial problem. I still have the exhaust to remove and inspect for any restriction, so will report back if I find anything there. Thanks guys !
