I went riding this past weekend and had a blast eating up anything from other 400's , banshee's to 250r's. I was riding all day then all of a sudden it quit starting. My problem is starting my ex. Usually you turn the key push the start button and bam it starts. I get nothing, no click no nothing, I just replaced the relay next to the battery, the fuses are fine. Can the actual button on the handle bars be bad? What else can I check, any help would be great!

How about the kill switch?

Hahahahahahahahahahaha!

Sorry, I AM weak!

Seriously, there's a li'l ol' 30 amp fuse I'd check first (after the kill switch, that is). Ah, but you say you've checked that. I'd check to see if the starter solenoid (and the neutral switch solenoid, if it has one) and its connectors had shaken loose. Then, I'd turn on the switch and jump the battery hot wire to the starter motor. Then, I'd start chasing wires with a volt-ohm meter and, one hopes, a wiring diagram. Good luck.

Tree Farmer

Very funny, serious I need some insight on what to check! If I clip the two wire leading to the start button and then touch them and if it starts then it the switch, other than that, I taking a shotgun aproach and they can get very expensive!

Well, yeah, you can jump the starter switch to diagnose whether it may be the problem; a volt-ohm meter is a better tool because you can tell whether you have juice to the switch and continuity in the circuitry . . . I suspect you have a loose connection in your starting circuit, most likely a solenoid control voltage (electromagnet) lead. Press on!

With the ignition switch on, you should have voltage to the hot side of your starter switch (you should always have a connection to ground (through the solenoid winding resistance) on the other side, with the ignition switch on and the quad in neutral).

With the ignition switch on, quad in neutral, and the starter button pressed, you should have a voltage at the hot side of the starter solenoid, a ground on the other side.

You can perform a quick check of the starter solenoid by hot-wiring it; if no action, jump to the starter motor and see if it turns over.

You can isolate components and segments of the circuit with a volt-ohm meter (VOM) to locate the problem. I think you can buy even a digital VOM for about $ 10 at Radio Shack or some such store; might not be a bad idea.

Tree Farmer

I had a similar problem with my 300EX I had, sometimes corrosion builds between the contact in the start button, underneath the button there should be a small hole where you can scrape the contacts with a scratch awl or something, also I had a problem with the switch on my clutch lever wouldn't allow me to start my 400ex in gear so I took the switch off and cleaned it and haven't had any problems since.
Hope this helps you out.

Thanks everyone, I'll try these few tips and let you know how everything went.

99' 400ex, DG nerfs, E-Series full system, Lonestar +2 A-arms, Axcaliber +4 Axel, K&N Filter, Works Triple rate shocs front, ultra cross rear.

Ride Red and ride hard!

I've encountered 2 problems with mine.

You can easily diagnose the starter button and selenoid suggested by some by turning on the headlights, if they come on, then the problem is somewhere in the starter circuit. If not, then you probably are encountering one or both of my problems. Read on....

First, the round solenoid ahead of the battery will come out of it's holder if you jump a lot, mine eventually pinched the small (16-18 awg?) red wire and broke the conductor inside, no power to anything, fixed the wire, problem solved. Use a small wire tie (tywrap) to secure the round solenoid in it's holder so it cannot pop out on big jumps. Mine goes over the top of the solenoid, between the two terminals, then around the bottom of the holder...

Problem #2, loose battery connections. They will eventually work themselves loose. First was the negative side for me, then a couple months later, the positive side, cleaned them both and loctite'd....

Its funny that you mentioned the headlights. I had lost all power up front the only thing that works is the key switch. the head lights stoped working. But if you jump the solonoid with a screw driver with the key switch on the machine will start, if you turn the key switch to off the machine shuts off, so i know there's power to that. I will check that wire you mentioned! Thanks

Take your front fenders off and start checking/cleaning those 2 plug-ins that attaches the wiring harness to the lighting and ignition. That could be the problem.

ahhhhhh u can still go riding put it in a gear push it down a hill and let out the clutch