Sorry guys, but I needed an attention getter for the 400ex owners out there. Has anyone else noticed (especially you Gabe) that the subframe starts to sag on the left side? My grab bar sits about 1/2" lower on the left side as opposed to the right side. My seat actually sits a little crooked. I figured out why in case anyone cares.

The factory put a bend in the lower tube right near the battery. The subframe actually bends OUT away from the swingarm at this point and lowers the left side. The reason why is that the battery weighs much more than the pipe and the bend also is the weak link on the subframe. If you go aftermarket pipe (weighs less) the problem multiplies. I have never crashed or rolled my quad, but I jump a lot.

I plan on trying to fix mine by buying a K&N that attaches directly to the carb, losing the airbox, and building an aluminum battery box in the center of the subframe instead of the outside. Of course, I will pull the subframe back to its original position.

TMM makes a subframe for $500 that all the arms are straight, I bet it will never have a problem, but I don't want to spend money on that unless I have to. I am hoping that my fix will take care of the problem also.

A friend of mine has had his for just under 6 months and Honda is going to replace his subframe. I guess they are about $400. I say it is a design flaw and should be corrected by Honda. Other than that, I have no complaints.

How many of you have this problem? Go out in the garage and LOOK, most might not notice. There are 8 guys here with 400exs, 7 are bent.

 

Well first of all, have you rolled it over before? If so, that *could* cause your bent subframe. A buddy of mine rolled his and bent his subframe EXACTLY as you described it. Also, just a FYI...the subframe cost $128 according to my local honda dealer.

Ooops...I just re-read your post and noticed that you did not roll it. Anyways a new rear subframe is still $128.

Eric

 

I know this isn't a 400EX but my quadsport has the same problem except in both the front and the rear.

 

I also have the same proplem. The left side sags. I went to the dealer where a buddy of mine works and pointed it out to him on the floor bike and asked hime what was up with that... He did not know.... I am going to try and get more info...

 

Before I read this post I was going to ask if any body subframe was bent. I noticed my left side fender was saging a bit a couple of weeks ago, And than yesterday I noticed the rear grab bar. I realy dont think it is a big deal as long as the problem doesnt get worse.

 

Hey i have the same problem and i was wondering why. I have wrecked mine a couple of times but i didnt think hard enough to do that. cool now i know

 

yea my 300ex is the same.....on the right rail of the grab bar the fender is like a 1/4" off it and on the left it like 3/4"......I don't think its been rolled bad by the dude that had it before me....it doesn't reallt bother me though...later

 

so skunky,
a brand new EX on the floor had this problem already? That means it normal right? if so, is CT aluminum air box the answer (it mounts the batter inside the box)?

 

I think it is more than the battery...

 

It is, it is the subframe being bent on the left side as opposed to being straight on the right side. I am assuming that the battery is the cause since it weighs about 15-20lbs. But when metal tubing is bent, that is the weakest spot on the tube.