250r rear brake swap on 400ex

[hondaREX]

Got some time before my winter engine build so i figured id start a post on a 250r rear brake swap onto a 400ex. For 250r parts i have a Duarablue adjustable axle, Durablue anti-fade brake hub, stock caliper, and caliper mount. I ran into a few issues so any feedback would be appreciated. Ill let the pictures do the talking.

First is a stock 400ex caliper for comparison

[hondaREX]

This is the 250r caliper, mount, Durablue anti-fade hub and stock rotor and 400ex axle. My first question is, what position is best for the caliper? I cannot remember the stock 250r location for the caliper but can quess its close to this because the mounts seem similiar. Ill try to get a pic of the web of a 250r for comparison.

[hondaREX]

This is the 400ex axle with the 250r Durablue hub. The snap ring is almost not exposed at all. I had to use 3 flat head screwdrivers to get it off. A second person would make it a breeze though. Also, the hub only took about 3/4 of a turn to tighten it to the snap ring. Dont think this would be a problem as the hub has the pinch bolt. Ill try to throw a stock 400ex locknut on it to see where it sits.

[hondaREX]

This is the 250r Duarblue axle, and 250r Durablue hub. Plenty of room to get to the snap ring. I dont plan on using this axle as it adds 2 inches to my width at its narrowest position.

[hondaREX]

So the only other problem that i encountered that i dont have a picture for yet is that the front most caliper mount bolt is real close to the swingarm. I had to mount the front bolt all the way in and the rear not even mounted. Then slide the rotor onto the axle and pivot the caliper mouint over the rotor and tighten the front bolt that little bit with an open end wrench and then the rear bolt. Not a huge deal but worth mentioning. Ill throw some new pads on it and see if the caliper lines up and rolls without dragging. I also threw the whole 250r axle in the carrier with a sprocket on it. The chain looked to line up perfect. Ive read in other threads that they needed to shim the carrier. I didnt have to. This was with 400ex carrier though so maybe it is different with the 250r carrier, ill try that when i get a chance too. So overall it seems to be an easy mod. All that is needed is the 250r caliper, caliper mount, caliper mount stay, rear rotor and hub. Let me know what you all think and any questions. And what caliper location is best or if either should work. Ill try to go for a ride to test it out.

[hondaREX]

After looking at some 250r pics, it looks like the caliper is in the same location, so its safe to say its in a beneficial location. After all.....its on a 250r!!!!

[Rich250RRacer]

Why not just do this? Much more economical, parts are easier to get, and there's no issues with it.

http://www.exriders.com/vbb/showthread.php?s=&threadid=155875

[hondaREX]

This is true. To each his own i guess. I happened to have the 250r parts and havent seen the mod anywhere and if i did i cant find it now. I dont believe theres any issues with the 250r setup other than having to assemble it with a little thought. If i go to build my 250r again, i might go with a 450r setup for either the R or the EX. Thanks for the info tho.

[riotact]

If you end up using the 250r axle remember you'll have to use the 250r rear hubs because the splines are different from the ex.I've been running a 250r axle,450r antifade and brake setup and it is definitely nice I think you'll be as happy with your setup.

[hondaREX]

Yup, i know that the hubs are different. Ive got a couple sets of 250r hubs. The Durablue would be nice but it is just too wide for my riding areas. And my stock 250r axles are all beat up so im not going with one of them on the EX. Theyll be there when i build one of my R's. Im sure the 250r caliper will be a huge improvement plus im putting a SS brake line on it too so its going to be a night and day difference. Wont be able to report on it till spring but i will when i do get to ride it.