I am thinking that maybe it is something in the clutch system being locked up. If the centrifugal clutch system isn't disengaging properly, there could be a load pulling the engine RPM too low to keep running.
Try and make it happen again, but then quickly pull the plug and check for spark. Or does the machine always start right back up once you pop it into neutral? I'd go ahead and try kicking it over with the kick starter with the plug out (looking for spark) with the machine in 1st gear to see what happens.
Try to figure out if it is the ignition dropping out, or something else.
@ PS2fixer: Is the neutral safety wire you mention just an interlock on the starter relay (so you can't use the starter button if not in neutral) or does that actually stop the system from providing spark to the plug somehow? My assumption (in the advice that I provided above) is that the circuit is simply a starter relay interlock, but he still be able to get spark by kicking the machine manually... let me know your thoughts.
Last edited by wonderboy; 10-25-2018 at 09:26 AM.
- Frank
1984 200ES Big Red
1985 350X (x2)
1986 350X
1986 250SX
1984 Auto-X
1984 ATC70
1985 ATC70