[JERSEYDEVIL]

1st off do the same test w/ the plug grounded on the motor in case the frame isnt giving you good ground, if the surface of the frame is painted that would give you a false reading. second make sure you have good battery power, this 250 is DC wired meaning the cdi is powered by the Batt and not the flywheels AC power like on older 150s. if you know the plug is good then the next thing would be the coil. even before i had a shop i kept spares in my tool box to quickly diagnose if a coil was bad instead of messing around with ohm settings on my multimeter. check the plug boot that the tip of the plug isnt loose and the wire is screwed in to both the boot and the coil. cdi's usually show signs of miss firing before it would a no spark issue but not to say it cant be a cause. if you can verify these components are good, then the stator/pickup may be next. remember to check all of your grounds. a motor can be perfectly grounded but if the stator ground is not grounded that could cause no spark......hope this helps.