kfx400 questions

[js3350z]

1) i have read about the z400 frame problems, does the kfx have the same problem?

2) What is your typical maintenance on the kfx400?

3) what is the HP differance between the 400ex and kfx400?

4) is there any typical problems that the kfx400 have, over other quads?

5) how often are you supposed to rebuild the top end on the kfx400?

6) which would you get for mostly trail ridding, maybe some MX (don't know about that yet) kfx400 or 400ex?

thanks

[UbeenSmoked]

well the 03 frames wernt to bad but they were weak and now the 04 and 05 frames should have had the problems bugged out but still if ur jumping and etc ur putting stress on the frame, so it would be a wise choice to gusset it.

the kfx is faster than the 400ex stock and would be same way when u mod it out

u shouldnt have to rebuild the top end for a long time

i would take the kfx over the ex anyday casue of its reverse

maintence on it would be the same as any other ordinary quad, tighten chain, keep up on oil/changes, etc

i have not had any problems with my kfx

[04-KFX400]

Read the latest Dirt Wheels. They did an 05 Z400 vs an 05 400EX shoot out. They trashed the EX and picked the Z in every catagory.

[400exrider707]

Originally posted by 04-KFX400
Read the latest Dirt Wheels. They did an 05 Z400 vs an 05 400EX shoot out. They trashed the EX and picked the Z in every catagory.

I should hope so cause the z got a bunch of improvements and the EX got reverse. Also plan on the EX being more reliable than the Z/KFX/DVX. They are a more high tech engine, and they are faster, but probably a little more maitenance. A lot more aftermarket stuff floating around for EX's, but The Z trio is getting up there. Either way you really cant go wrong.

[BlackRaptor]

Get a 400ex if you plan on doing mostly trail riding and some MX, the 400ex is the way to go. the 400ex is only a slip-on away from kfx400 power. I bought a kfx400 used, and it sounded great and then out of now where the bike locked up and costed me $1400 to get fixed. The cam chains on KFX/Z's are junk. Most people replace them constantly or get an heavy duty one like I did. Plus if you ever get cams they will tear a stock chain right up. My stocker had kinks and broken links everywhere. The EX is way more reliable. The xr400 engine which is essentially the 400ex engine has been around for ever and has proven reiability. My neighbor has one and has never touched it, hes had it for 6-8 monthes and its a 2000 on the stock top-end, there good bikes. The power difference isn't that big either, so for the money get the EX. The kfx engine has only been around for a little while and it has some issues, if your not careful. I regret not getting a 400ex. And if you really want liquid cooled and aren't really into hard-core riding or what-ever consider the Raptor.

[kawasaki_ridah]

about the reliablity the z/kfx/dvx seem like they are just as reliable as the ex i have never had a problem out of my kfx i have rode the heck out of it too, not saying the ex isnt reliable it is they both are, and actually they are both a great way to go. the new exs look so sweet too!!! but you can get awesome deals on like 99-03 400 exs so i would look at that, and you can find a crap load of aftermarket stuff for the ex but if you are getting a new quad i would go with the z.. used ex

[kawasaki_ridah]

Originally posted by BlackRaptor
Get a 400ex if you plan on doing mostly trail riding and some MX, the 400ex is the way to go. the 400ex is only a slip-on away from kfx400 power. I bought a kfx400 used, and it sounded great and then out of now where the bike locked up and costed me $1400 to get fixed. The cam chains on KFX/Z's are junk. Most people replace them constantly or get an heavy duty one like I did. Plus if you ever get cams they will tear a stock chain right up. My stocker had kinks and broken links everywhere. The EX is way more reliable. The xr400 engine which is essentially the 400ex engine has been around for ever and has proven reiability. My neighbor has one and has never touched it, hes had it for 6-8 monthes and its a 2000 on the stock top-end, there good bikes. The power difference isn't that big either, so for the money get the EX. The kfx engine has only been around for a little while and it has some issues, if your not careful. I regret not getting a 400ex. And if you really want liquid cooled and aren't really into hard-core riding or what-ever consider the Raptor.


dude that is so werid i cant believe that urs locked up and craptors are not the great i think they feel like crap they sit way too high but they have great power, but i would choose a kfx or z 400 over one any day, i raced that dude and killed him and im stock and he had a pipe and jet kit. but dont trash a kfx the reason yours prob messed up is cause it was used i havnt heard of the "so called problem" and the z400 motor has been around awhile in the drz400 dirtbike

[z400quadmaster]

I bought my z used I was goin on price cause it was cheaper. I have it gettin serviced right now as I speak. The dealer called me and told me my valve shims were bad in the motor I really dont know what the r for but whatever alota things have broke on mine so far and im really gettin pissed at it but i cant complain cause the motor is really strong. I would really love ta get a yfz I think they r the best quads they just get some getting used to thats all but anywat i like my z so its all personal prefernce if u ask me but what ever.

[BLAZE1]

Originally posted by BlackRaptor
I bought a kfx400 used, and it sounded great and then out of now where the bike locked up and costed me $1400 to get fixed. The cam chains on KFX/Z's are junk. Most people replace them constantly or get an heavy duty one like I did. Plus if you ever get cams they will tear a stock chain right up. My stocker had kinks and broken links everywhere.

Wow, Now that is a problem!

Let me get this straight, you replaced the cam and then the stock chain broke or did you do the cam & the chain at the same time?? If you were already inside upgrading the engine why would you not opt for a new cam chain??

[BlackRaptor]

No, the bike was running fine, and I rebuild and to all my own engine work, I know bikes. Yea there was no slapping, knocking, tapping, the cam ran slack making no noise, the cams jumped time and the bike dropped a valve and just screwed everything up. If you don't believe my I'll post the F****** parts list, Sorry but the day that thing blew I don't think Iv'e ever been more pissed in my life. When I opened the bike up, the cam gears had small chunks missing, the cam chain tensioner was destroyed, the cam chain had broken links and it was kinked up. It was a disater form the base gasket up. The scum bag I bought it from screwed me. Don't get me wrong, the Z or kfx isn't some irreliable piece of crap, but I defiently, think it needs more attention, and meticulious care to keep it running right than the 400ex. Now I check the vavles after every ride, and the cam chain, change oil and the time, make sure I put exactly 2.2 quarts of oil in.

BTW, Kawasaki Ridah You can't say raptors are crap when all you've done it beat one in a race, and you say "It's tippy," Like i said before, if your into just trails and some MX with the right mods a Raptor can be fast as hell and still be stone reliable, Just get a 2002 or newer. Of course a Z will be a raptor on the track, the Raptor is advertised as a trail quad. Do you think your a freakin expert, on engines, first of all the XR 4-valve RFVC engine has been around since the mid-eigthies, So its been around a lot longer than the KFX, and you obivious don't relize the different between DOHC and SOHC, the difference in valve adjustments the simplicity. Kawasaki and suzuki, didn't put strong enough cam chains in those bikes, and with some previous abuse they fail cause catsoptroic engine damage. And did you know that its the same for cars like the old hondas such as the late eighties accord, If the cam chain or belt goes out in one of those, the whole engine blows up.

Blaze: the bike had hot-cams in it, they were put in along with a new chain 7-months before it blew up, so your guess is as good as mine for the cause of this crap.

Sorry to hijack your post. The best way to make your decision is to look in your local classified ads, Go look at and ride the bikes your considering and make your descision based on that. Don't base your decision over the internet. Good Luck. And of course be careful.

[woodsZrider]

I love my Z
no probs yet
I would pick the Z

[kawasaki_ridah]

BTW, Kawasaki Ridah You can't say raptors are crap when all you've done it beat one in a race, and you say "It's tippy," Like i said before, if your into just trails and some MX with the right mods a Raptor can be fast as hell and still be stone reliable, Just get a 2002 or newer. Of course a Z will be a raptor on the track, the Raptor is advertised as a trail quad. Do you think your a freakin expert, on engines, first of all the XR 4-valve RFVC engine has been around since the mid-eigthies, So its been around a lot longer than the KFX, and you obivious don't relize the different between DOHC and SOHC, the difference in valve adjustments the simplicity. Kawasaki and suzuki, didn't put strong enough cam chains in those bikes, and with some previous abuse they fail cause catsoptroic engine damage. And did you know that its the same for cars like the old hondas such as the late eighties accord, If the cam chain or belt goes out in one of those, the whole engine blows up.

Okay lol first i was talking stock i dont want to buy a quad and spend 3 grand or ever how much to make it good on a track and i have seriously heard of raptors having more problems than a z400 and no i dont think im an expert on anything i just dont see spending 6,500 dollars for a raptor when you could get a z that is better on the track but if i had 6,500 dollars i would get the yfz the raptor is outdated now! and you said it was a good trail bike im not sure but you barely touch the throttle and it will wheelie like heck its got alot of power and good top end your right it is very fast but i seriously do not think it feels good at all and the cam chains how come mine is still running strong?? seriously im not trying to be a @ss hole here if it is so weak what will make it mess up? and how can i prevent it.. i know it looked bad how i posted before but i didnt mean it the way you read it, i just dont like ppl knocking stuff

[kfxrider35]

dude go with the z/kfx not the 400ex its ok for certain things and raptors suck b/c they are top heavy just go right the first time an go with the z... how can you go wrong? it already has reverse and its faster than the 400.