Author Topic: KX5 died.... any input for the authopsy??  (Read 7027 times)

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Offline Sagid

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KX5 died.... any input for the authopsy??
« on: February 06, 2008, 01:45:31 PM »
Well I just got my self a KX5 last week, it is a 90 model that was sitting in some barn for a century, or so I was told. it actually does look really good for a 90 model.

So there I was as proud as I could be with my new monster toy.. I have been riding a vintage ?83 CR480 for the las 5 years or so... got tired of digging for parts.

Well the thing is that I went out to test the KX5... It felt really powerfull on the first trials... I noticed some not stable running at low RPM?s  and it was going off when idle.... didn?t really bother me ?couse it is ment to be hard ridden anyways.
So the next morning I took off the carb for cleanning, thinking the problem was due to lack of use and dust accumulation.
So I did my thing... not really a tune up.. it was pretty much removing dust on the outside with gasoline and a brush... I opened the carb and did the same thing on the inside.. made sure not to move the jet needle or the floaters valve.. put it all together again... installed a new air filter... I did turn the idle control screw about one third of a turn... So when evereything was in place I started kicking... on the third kick the bike starts and it when on full throttle like it was posessed!!!! I pushed the kill switch a hudred times and it didn?t worked... it only stopped untill it burned out the gas left in the carb. after that the compresion was... well.. was not there anymore... I openned the cylinder and found a blown piston ring. Not so big deal to fix.. but I?m more concern about knowing what the hell went wrong??? Thinking that this could happens when I?m riding the bike gives me the creep.

Any Ideas out there?? it?s a shame this is my first posting.

Offline Kawasakinut

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Re: KX5 died.... any input for the authopsy??
« Reply #1 on: February 06, 2008, 02:23:01 PM »
read my thread ( runaway two stroke ) as far as i know it could be a couple issues. they call it a runaway 2 stroke because even though you pull the plug this machine keeps on running or you push the stop start switch and nothing happens. could be the throttle cable but i doubt that because you hit the stop switch and it kept running. most probable is an air leak (carb boot) where air is entering the engine and you would not be able to regulate it. anyway check my post above for more and welcome to the site.     
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Offline KXcam22

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Re: KX5 died.... any input for the authopsy??
« Reply #2 on: February 06, 2008, 04:43:06 PM »
Sagid,
  I wouldn't worry, that is unusual.  It is possible your carb slide was stuck after the rebild but it sounds more like a lean runaway.  On those the kill button doesn't work since the extra-lean mixture is self igniting and stopping the ignition doesn't do anything. Have to put it in gear with the rear brake on.  For a start I would pull apart the carb and verify everything and set the jetting exactly like the jetting chart (search the site). That should get you close.  The KX500 runs very good and idles nice when it is jetted right.  Hope this helps. Cam.

Offline hughes

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Re: KX5 died.... any input for the authopsy??
« Reply #3 on: February 07, 2008, 01:57:29 AM »
Also make sure your fuel petcock is working correctly. Remove fuel line from carb place container under fuel line and turn on fuel cock. Should have a nice flow of fuel coming out.
Open Class 2-Stroke Kawasaki KX500
Yamaha 2005 YZ250
Richard Hughes
Dirt Hammers - Online Off-Road Journal
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Offline Hillclimb#42

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Re: KX5 died.... any input for the authopsy??
« Reply #4 on: February 07, 2008, 02:53:47 AM »
When you look in the carb the slide should close all the way. The cable should have just a little bit of play that you can feel in the throttle tube. My guess is slide is open or cable bound holding it open. I think it would do the same thing if the base gasket blew, but you could probably see that.
 Everyone is right and thats a good lesson that I learned. Brakes and hit second gear=saves motor. Don't start a bike on a stand either.
 That sucks man, you were supposed to post about the sweet k5 that you picked up in mint condition....and tell us about ripping off the nobbs doing 4th gear wheelies. Repost after fixing piston

Offline mdw471

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Re: KX5 died.... any input for the authopsy??
« Reply #5 on: February 07, 2008, 06:20:02 AM »
"Brakes and hit second gear=saves motor"

I am going to repeat this to myself 200 or 300 times so I don't have to think about it when/if something happens!!  :mrgreen:

thanks for the tip Hillclimb#42

Mark
for more information about the World's Fastest Dirt Bike, www.wolbrinkrace.blogspot.com

Offline dans89kx500

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Re: KX5 died.... any input for the authopsy??
« Reply #6 on: February 07, 2008, 12:14:50 PM »
"Brakes and hit second gear=saves motor" I dont understand? I never start my bike on the stand, but I alway see people who do. Why is that bad?

Daniel in Vacaville
Daniel in Vacaville
1989 KX500
2000 Husaberg FC501
2009 Husqvarna TC510

Offline Sagid

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Re: KX5 died.... any input for the authopsy??
« Reply #7 on: February 07, 2008, 01:30:55 PM »
Thanks all of you guys for your input!

Brakes and 2nd gear!!   of course!!! how come I didn?t think of that by my self????
oh yeah!! It?s just that I was so freaking scared that I couldn?t even think.... LOL

despite an embarrassing entry now I feel wellcome to the site  :-D

Offline Hillclimb#42

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Re: KX5 died.... any input for the authopsy??
« Reply #8 on: February 08, 2008, 01:07:46 AM »
 No way man, I'm not the genious here. I spent 1400 smacks on mine and then blew it up. This is just the aftermath and thinking what I should have done. Don't feel bad at all. I freaked out too. I hit the button, then pulled a dead-man switch for hillclimbing, then pulled plug wire and then the gas line. It melted the piston leaning it out like that. The cause was a slide partially open.
 Actually, starting the bike on a stand costs you valuable time, if you have to kill the bike. I was afraid that the 500 would overpower the brakes and go flying into everyones cars. I also have since considered that this method is not perfect by far. Using it to kill the motor in an emergency could still possibly bend rods or break cranks or at least be bad for bearrings.
 The real trick to this is to be ready for it and if worse case scenario hits, you kill it immediately and fix it. Sometimes a guy will forget to have his gas on and it will start revving up off of idle. Its leaning out, heating up, melting down. You just have to be in tune with your bike a little and be ready to stop it. Even if you freak out or crap your pants don't let it rev to the moon on its own. 10 seconds and it is done...... :evil:

Offline KXcam22

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Re: KX5 died.... any input for the authopsy??
« Reply #9 on: February 08, 2008, 05:49:56 AM »
It's quite normal to be caught unawares when a runaway happens and then get lost for ideas when the killbutton doen't work.  Cam.

Offline Kawasakinut

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Re: KX5 died.... any input for the authopsy??
« Reply #10 on: February 08, 2008, 01:03:30 PM »
glad i'm not the only the only freak here. hahaha
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Offline Sagid

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Re: KX5 died.... any input for the authopsy??
« Reply #11 on: February 12, 2008, 03:45:47 PM »
Ok Now.... I found the root cause!!
 The last three threads of the throttle cable sleeve were split and pulling the carb slide... should have noticed that there was no play at all on the throttle. Shure I will not forget to check this again now after I got to learn on the hard way.

Anyways... I fixed the blown piston and took her for a ride last weekend... Boy this bike kicks ass!!!!
I could climb a wall on this thing.

I don?t have riding buddys since Im new in town.... and I gained everybody?s hate now I made my first incursion blasting ?em all... LOL even the big quads got to  eat my smoke... :evil:
The K5 is really like the yetti here in Mexico... so now I made some guys the favor to know how it feels to be smoked by one... LOL
I checked out the bike and it is actually all stock except for the renthal bars.... What would You guys recommend to be the first upgrade.

Sagid.




Offline holeshothirons

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Re: KX5 died.... any input for the authopsy??
« Reply #12 on: February 13, 2008, 09:39:51 AM »
would you get electrocuted if you tried to pull the plug cap off to stop the engine ?

Offline Sagid

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Re: KX5 died.... any input for the authopsy??
« Reply #13 on: February 13, 2008, 01:31:01 PM »
Certainly you would not die from an electroshock... or at least i have not hear from nobody who has...
but for shure you will for sure feel the spark!!!! hehehe i have done it before.. not with a K5 but with other bikes
dude!!! it?s lot worse than the 110V you feel when if you gtouch a stripped wire from any outlet in your house.
everyone should give it a try hehehee  :mrgreen:  this is what you will look like afterwards.

cheers!!

Sagid.

reesedp

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Re: KX5 died.... any input for the authopsy??
« Reply #14 on: March 31, 2008, 08:44:56 AM »
I think the first upgrade should be a chain stretching from the swingarm to the nearest tree for the next time you try to start it!!