Hi, I have some questions about putting a 450r shock, on a Honda 400ex 08.

What year of the shocks, will be best for the 400ex?

Are there any issues with putting them on the 400ex? Like the height will be too high.

If I have 1.5 inch wheel spacers, will it fit?

I've only seen people talking about front shocks, so should I also get the rear shocks? If so, what will it improve?

I do mostly slow trail riding, and fast open areas.
Thanks.

 

Any year trx 450r shock will work and wheel spacers will not change anything.
You do have to alter the upper shock mount a little bit. There is a welded nut on the bottom side of the shock mount. It will have to be removed. I used a dremil tool to grind it off. The nut is for a bolt that holds a bracket for the front fenders. You might also have to use the dremil tool to grind down a SMALL amount of the upper shock mounting bracket buy the frame so the bolt hole of the shock will line up laterally with the bolt holes in the shock mount. Now you need to get 2 small pan head machine bolts (same dia.as the ones removed) and nuts to hold the bracket for the fenders. The bolt (head down) will go through the shock mount so you can mount the fender bracket. The new shocks will feel stiff if you do not adjust them. Mine are adjusted so the ride height is as tall as possible and the rebound and compression are at full soft.
The 450r shocks are also a good platform to build from. You can always have valves replaced for your weight.
Now the rear 450r shock will fit on the ex but there is no real benifit to it. It will give you less travel and the rear will sit about 1" lower than with the stock rear shock.