Hello,

I am new to this forum and plan on purchasing 2 KFX 400 quads next week. I was wondering if anyone has had any kind of problems with these bikes? Also, what kind of "homemade" mods can be done to increase the power? I was reading in the forums about airbox mods, but I think that was talking about another quad.

Thanks for your time!!

Chinchin[img]i/expressions/face-icon-small-confused.gif[/img]

 

That is the Hundred Dollar question. You will get two completely different responses from this post. There are some that will tell you that their KFX400 has been flawless, of which I am one of those people. Then there are those that will tell you that the frames crack and the axles bend, and the rear brake rotor will warp and squeal.

This is what I have come to understand from reading several of these type of posts.

1. The Frames on the Z/KFX are not the strongest frame in the world, but for the average rider, they will work just fine. They appear to have a problem around the top of the front shocks. In Most instances the people that have had problems with cracked or broken frames are people that have either hit things with their quads, or are very aggressive riders that do a lot of jumping. The problem stems from bottoming out the front shocks on the landings.

2. On the early Z's the Axles were weak, but by the time the KFX's were produced, the problem had been solved. Some may have still bent their axles, but the occurrence isn't any greater than with any other quad. So as far as the KFX goes, I don't think that it is of any concern.

3. Rear Brake Rotor. While I haven't had any troubles with mine so far, I have heard several reports about the Rotors warping and squeaking. Point of interest, brake parts are not covered under the warranty.

Take this for what it is worth. I have No doubt that there are those that have had troubles with their KFX400, but for every one that has had a problem, there are a 100 that have not. Good luck.

 

Go for it... the axle problem has been fixed and if you are worried about the frame, the only major weak point is on the shock mounts, and if you are worried about that, you can buy a "brace" for this which will add strength for around $100. I personally have not had any problems and I ride very hard. The frame issue varies from person to person. Not sure about any "homemade" mods but do buy a pipe, filter, and re-jet which will wake your bikes up immediately. Good luck!

 

Thanks for the post fellas! The info is greatly appreciated. As far as the weak frame I am not worried as I can have someone weld a piece of metal to support it. The break warping might be an issue but I am sure I can modify the brake system if needed. Have you got an estimate on the jet kit pricing for the 400? I plan on buying pipe for it ASAP.

 

Be sure and check on the HMF Slip-On. Just ordered mine. It's pretty impressive for just being a Slip-On.

 

Will do Thanks!! One more question. How much do dealers actually mark up on these quads??? I believe since I am buying 2 that they will give me some kind of discount.