On my yz250 had no spark, figured out it was my stator, so i put a new one in and it started right up. rode it for 5 mins quite on me again and have no spark...traced the problem to the stator again??

SOURCE: will not start no spark

There is a black and white wire near the coil the should be for the kill switch or on / off if you unplug that wire you will bypass the on / off switch.
The CDI unit on the Yamaha often does not provide a very bright spark and it's often very hard to see in daylight. First make sure you replace the plug, second make sure you have it grounded well on a part of the engine. Make sure you have something covering the spark plug hole because if gas comes out of the cylinder and the plug does fire you can ignite the bike on fire. (I know that one from experience). I'd be willing to bet you don't have an ignition problem unless the key is shorted out. Sounds like the bike was running fine until you shut it off and then would not refire, did you try to push start it?
First things first, double check the spark, like I said it's VERY hard to see in daylight.

SOURCE: 2006 crf100 no spark

You have 2 basic possibilities,

• A kill switch is active
• The ignition control module has gone bad

SOURCE: Replaced stator, brand new battery, died after 10k ride

sounds if regulator is not working or poor connections within charging circuit

Earl Norager

• 355 Answers
• Posted on Aug 19, 2009

SOURCE: katana died with full charged battery

SOUND LIKE VOLTAGE REGULATOR IS NOT WORKING CHARG BATTERY AND GET VOLT METER AND START IT UP AND HOLD RPM AT 1500 AND YOU SHOUL BE SHOWING 13.95 OR MOOR HOPE THIS HELP IF NOT AT LEAST 13.5 VOLTS THEN YOU MAY HAVE BAD VOLTAGE REGULATOR

Testimonial: "thak you very much"

SOURCE: i got a 01 yz 250 it gets spark every once in a

if the coils and CDIs have been replaced, you may want to check your wiring, this is usually caused by a damaged like grounding the frame and affecting the spark.