I have had my 400 for a week now and its been shutting off while riding. It doesn't seem to do it when i been riding fast or slow, or when its wet or dry. And it usually only does it 2-3 times a ride,,if at all.

It shuts off like someone is turning off the killswitch. When I go to try to start it it just cranks over but doesn't start (like the killswitch is off).

I mess with the killswitch some and then it will start right up. But i am not sure if it has to do with the switch though because sometimes it doesn't seem to start after messing with the switch.

I called the dealer and they said to check the battery cables and fuse and that. But if they were getting loose it wouldn't let the bike crank over.

Any ideas before i have to drop it off at the dealer and have it sit there for 2 weeks?

Thanks
chris

 

Check that the breather hose or gas line are not getting crimped down under the seat or the breather hose on the top of the tank is not getting crimped when you turn the bars.
That will do cause your symptoms. Tighten all terminals for the battery. And make sure your spark plug boot is tight around the plug.

It almost sounds like your running out of fuel. EI: slow recovery rate. Yeah..check for fuel flow.
Pull the gas line from the carb and turn the fuel valve on. Does it flow smoothly?

 

it could be a short in the wiring somewhere.a wire could be rubbing and shorting out

 

I actually took my bike in to the dealer after about a week because of a similar problem. My bike would start missing and then it wouldn't run. They told me it was a dirty coil. Sounds like BS to me but it's been fine ever since. The coil is in a bad location, right up under the gas tank on the left side. It gets lots of crap on it when riding. Take it off and clean all the connections. I covered mine with that electrical tape in a bottle, brush on stuff. I've had my 400EX covered in mud and not had any problems since. Also, I've heard of some CDI box problems. CDI box is up front under the front hood plastic. Good luck. If it's under warranty I'd take it in and let the dealer troubleshoot it.

 

After picking up my 2000 400EX last January, shortly after my first few rides, I noticed several nuts and bolts on the quad which had either vibrated off, or loosened significantly.

One of the bolts which had loosened was the main ground wire (heavy gauge black wire from the battery screwed into the frame of the quad).

Due to this, I would check every and all connector, nut and bolt on your 400EX related to the electrical system, as the problem you are describing is certainly related to the electrical subsys.

 

Check your neutral switch connection its under the front sprocket and also check all electrical connections to make sure they are secure could be those also