Items prone to fail on the 500?

[shostang]

Does anyone have some sort of list of things that are known to fail on these bikes?  Just so I can address them before the race and have a smaller chance of something breaking/failing.  I'm rebuilding the bike for the Vegas To Reno race this summer, and want to make sure everything has been addressed.  Sorry for the noob questions, my main bike is a YZ426 and I bought the 500 specifically for this race.

Thanks for the help. 

[jfabmotorsports.com]

The YZ426 is what made me buy a KX450f. I still have the 426...love it. If the 500 is used it more than likely needs all the linkage bearings replaced. I have bought countless used 500's and not one has had a full set of good swingarm/linkage bearings. Next, check crankcase seals. Those have been my two problem areas.

JAFB

[Mick]

Does anyone have some sort of list of things that are known to fail on these bikes?

Everything 
...but here's a few things mine breaks continually, in no particular order:
1.  Pipe mounts
2.  Silencer bracket
3.  Drive side rear hub bearing
4.  Kickstarter
5.  Every fastener not loctited disapears
6.  Frame behind the engine cradle, near the footpeg brackets crack
-and a few isolated episodes:
7.  Plating came off the carb slide
8.  Electrofusion flaked off the cylinder (caused a huge d**n mess)
9.  Water pump impeller ground it's teeth away

But I've never had any infamous tranny or otherwise engine related problems aside from the above isolated incidents.

[KXcam22]

Your Nerve.........

[jdcowboy]

Your Nerve.........

Definitely get some extra doses of nerve.

My recommendation would be go over the bike really good check every nut, bolt screw on the machine to make sure they are tight.  When I got mine they all needed to be tightened.  Still I lost the exhaust bolts.  Locktight can be your friend....until you have to remove that item again anyways.

Good luck.

[turtle22]

it would not hurt to have the shock rebuilt. ive have to do that on both my 500 that i desert race. they take a pretty good pounding out there. the seal head likes to leak after awhile.

[Polar-Bus]

Does anyone have some sort of list of things that are known to fail on these bikes?  . 

The rear tire knobbies?
Chains and sprockets ?
Your forearms?       

[Johnniespeed]

 Pipe mounts
 Pipe mounts
 places where the pipe mounts attach too
  Rear tires
  knobs on rear tires
 Did I mention pipe mounts and rear tires ?

[turtle22]

oh and most important thing that is common to fall of; the rider(if not holding on tight)

[barryadam]

The above posts list the first items to go.  But on the KX500, EVERYTHING is a wear item.  And I mean EVERYTHING.  I've replaced a cracked airbox, Baja Designs dual sport stuff (horn, horn mount, metal headlight bracket, blinker relay, headlight wiring connection, headlight, etc.) all from wear, not crash damage.  My rear license plate and rear led light both broke from the vibration!  Renthal fatbars cracked (Ok, so those might have ben a manufacturing defect). The radiator screens fall off because the mounting holes in the radiator's aluminum flanges have enlarged so much.  The tank/radiator shrouds crack from the vibration.

I've had my crank aligned and all new bearings in the motor, so it's not an engine maintenance root cause.

I don't seem to be distributing fasteners all over the landscape like other folks, and I have not been using Loctite.

Oh yeah, one of the "fail" items right up there with the pipe mounts is that the chain grinds it's way through the subframe leg.

[Johnniespeed]

 A little clear RTV silicone on the plastic radiator grills at the mounting pegs will keep you from spending fifteen dollars at the dealer.
 I bought a nice big bag of those special 8mm hex head 6mm bolts from a member here, I plan to distribute them all over the landscape, so when other KX500 owners need one, all they have to do is look down.
 What is  the high score for number of pipe mounts broken ? 
John

[demographic]

This thread might help you out with some of the faults and fixes...
http://www.kxriders.com/forums/index.php/topic,434.0.html

[Ahole500]

i've killed 2 kickers,snapped rite off.

[martinfan30]

i've killed 2 kickers,snapped rite off.

Curious, where are the kickers prone to fail? Where do they break? With a good kick start routine, can this be avoided?

[snoopjonnyjon]

Well, I've owned my KX500 for about two weeks, and it seems the weaknesses listed are true. This is on a one owner, original tire (since replaced if you noticed the Maxxis rear on it) bike I bought that he estimated had around 20hrs total time, not an old clapped out raced bike.


Upon getting it home I noticed the subframe was worn by the chain. After reading the pipe mount tab on the frame breaks off, I discovered that was also the case on mine. And the last time out riding it I broke two of the little rubber pipe mounts, and broke off the kick start lever (apparently 02-04 levers are beefier, so that is what I ordered). I also lost the bolts that hold the silencer to the subframe.

Also, the little rubber cones in the top triple clamps were distorted which made the handle bars look bent. And the lower pipe spring was lost, presumed broken.

And as other people have said, they like to eat rear tires, and drink a lot of fuel!