Someones been messing with that axle nut. It looks a little rounded over.

 

Oh ok. I will give it a shot tomorrow after the rust check has had a chance to soak in. We couldn't even budge it earlier. Mite have to heat it up. I'm pretty sure the guy before me didn't take care of it. I changed the oil + filter and the filter was black as hell.

 

Two pipe wrenches should work well. They can be a pia sometime. Just keep picking away at it. Iam doing a rebuild now, mine is a 02. After 10 yrs. they need a little attention.

 

Is it really bad? I mean the axel is tight and doesn't move. Because I'm going riding Saturday and I dont wanna crank and heat it up too much and end up screwing it up and not being able to run. I don't ride too hard just trails. I plan on doing a lot of work to it in the winter. I can tell the other guy didn't do anything. There is even mud caked all over the motor that I have been slowly scraping off.

 

That 1/2 inch space between your axle nut and disc brake flange is normal, the way your disc brake moves I would say the splines are worn either on the disc brake flange or the axle, or both. You need to get the axle nuts loosened and the outer nut needs to be snugged up all the way to the retainer ring and then tighten the stop nut tight up against it. As mentioned previously, these are reverse thread.
If you cannot move your axle up and down in the carrier while the quad is jacked up, your bearings should be fine. When the bearings go out on the 400ex, it's very easy to get the axle to wobble in the carrier.
You should be OK to ride it but an inspection of the axle and brake flange would be recommended in the near future.

 

Thanks for all the info guys. At the side of the rode ATM. The guy before me didn't put a coder pin in the castle nut on the back tire and it flew off ruining my Saturday big ride. Now I know better to check all this things before hand I guess.

 

Man that sucks!!!! Did you mess up the axle?

 

Nah it's fine. The tire just kinda rolled off. Just need a new castle nut and it will be good for next weekend when i finally get my trail pass for the groomed trails out here and won't have to ride the brutal rocky ones.

 

What size tires do you have? Iam running 20". I'll take a pic of my old 1/4" pro armor swing arm skid plate. 2 years and its time to replace it. The castle nut is a 17mm. You can probably get one at a hardware store.

 

It has 20" maxxis razor2's on the back.