This isn't a problem with the chain, but with the tightener ring thing. I loosened the 4 allens. I have tried channel locks, 2 screw drivers, and smacking it with a hammer and a flat head. The damn thing will just not budge. I tried prying apart the housing where the bolts clamp down on AND trying to move it at the same time,, still nothing. Help please, I really wanna ride this weekend.

 

Remove the 4 pinch bolts then use a large flat head screwdriver as a wedge to spread the swing arm from around the carrier.
There were times when I would have to spread the swing arm then use a punch and hammer to get the carrier moving. Dont just hit the carrier with a hammer. They will crack rather easily.
I have also used a plumbers chain spanner.

 

I tried that, even with 2 people. And I pretty much ruined the carrier last night, so I just ordered one from Superatv. Will not get to ride this weekend, but oh well. I discovered last night it also needed new bearings, so this is a good investment. I also found another problem. I can not get the axle lock not to budge at all. I used tons of penetrating fluid, and a large pair of channel locks, and the thing will not break loose!! Getting fed up with this thing, this is the first 400ex that I have ever seen with this much stuff overtighened and not lubed properly.

 

Axle nut is reverse thread and IIRC there is a clip on the axle hidden by the nut that has to be removed. My axle nut wrench was a 3' pipe wrench. When you re assemble and are done wrap the axle nut in electrical tape because they are known to loosen up. I would also put a small amount of anti seize in the swing arm where the carrier goes. It helps with rotating carrier to tighten the chain long after the project is done.

 

I did not know they were reverse thread. thanks. And I decided to get a whole new carrier, a double row one. And I am going to grease it up real nice before i put it all in. Thanks for the help man