CRF450R cutting out - why?

[Spokes574]

My Y05 CRF450R cuts out on me when riding it within first 1/2 lap.

-when hot cuts off at 1/2 or full throttle in gear while in motion, then has difficulty kicking on, I have to push off the track.

-If cuts off and engine is warm, I can kick bike back on but when ride it in gear for about 30 seconds it shuts off again.

-When cold and in garage turns on first kick. Seems to be an issue once bike is in gear and is hot.

I replaced spark plug.
Valve clearance if fine.
Fuel is coming out of fuel line fine.

What is going on? Rich are you reading this, if so help.

Spokes574

 

[Rich Rohrich]

Sounds like you might have a component in the ignition that is failing when it heats up. Stators can do this and so can the ignition coil. It's possible that it's the CDI box but that seems the least likely.

Looks like it's time to break out the multimeter and the Service Manual.

 

[BSWIFT]

Meter the stator and the ignition coil on resistance when the bike is cold. Then start and warm the bike up. Meter both again. If you see a sharp increase in resistance on one of the components, you've likely found your problem.
Many people refer to electrical problems as a "short" but in reality, most electrical failures are "opens". A "short" is little or no resistance or continuity and an "open" is infinite resistance. Be sure to check all your ground connections and inspect all of the wiring for nicks or cuts in the insulation. A long shot problem could be the spark plug cap. When the material heats up it may be letting the spark jump to the head and not the spark plug. I've seen this on rare occasions. If the stator and the coil check out good, replace the spark plug cap.
In the event all of these components check out good, find a buddy with the same bike and swap the CDI units. If your bike runs right, you've found the problem and it is likely to be the most expensive of all the components. Best bet is the stator. Good luck.

 

[Spokes574]

Thanks you guys! I dropped the bike off at the honda dealer and they also think its the Stator or ignition coil. I left them with a spare race CDI box that they can also test the bike on. I will report back what they diagnose it to be.
Thank you Rich and BSwift.

Spokes574

 

[conn424]

i had a problem with my stator coil when the bike got hot it just shut off, half the little bearing things in the stator were gone. Also the valves causes it to cut out.