throttle sticking (help)

[89kx500]

went to the track two weeks ago and while powering thru the whoops when i came out the throttle stayed open,i hit the kill switch brought it home. during the week i checked the cable theres no bind its routed properly, i pulled the carb and checked the slide, there was no wear and it was clean.put it back together yesterday and went to the track,made about four laps when powering up a tabletop it happened again,only this time it hurt,collapsed lung fractured ribs and seperated shoulder, when a 500 verses trees and rocks outside the track,trees and rocks win,i couldn't kick the bike away or find the kill switch, any idears as to whats happening??? the throttles free it only happens while riding ??[/b]

[gowen]

It sounds like your running out of fuel or very low, your float height may be very low, when the KX runs out of gas it tends to hammer wide open due to a very lean mixture. I would assume your jetting is very lean and it is sucking the bowl dry or just a very lean mixture.  I am sorry to hear about your accident, I had one of those last year and it was not cool, hope you heal fast!

[Kawadougie]

I used to have a 1991 KX-500 with a similar problem.  After I ran the motor for a while, the carb body would distort slightly and bind the carburetor slide in the bore just enough to make it stick.  As soon as it cooled down, it would move very smoothly.  I messed up both ankles after stepping off at speed and then replaced the carb with an old round slide and had no more problems.

[doordie]

89kx500,

Check gasroll,plastic and crack easy,you can use search function and look
what happened for me last year.

//doordie

[89kx500]

thanks guys,
i cleaned it up last night and started making a list of parts that had to be replaced.
i'll start pulling it apart this week, the strange thing is that right after it happenens the throttles fine,
i think gabes on to something with the fuel
                                                                    sean

[teamgreen500]

Throttle tube catching on handlebars while riding? aka "Friction"...

Just wondering...

[89kx500]

the throttle tube returns to normal position,i checked that as well,
                               thanks

[hughes]

I used to have a 1991 KX-500 with a similar problem.  After I ran the motor for a while, the carb body would distort slightly and bind the carburetor slide in the bore just enough to make it stick.  As soon as it cooled down, it would move very smoothly.  I messed up both ankles after stepping off at speed and then replaced the carb with an old round slide and had no more problems.

That's weid dude. Becasue your carb should not heat up it has cold fuel and air flowing through it.

[Rowdy-Yates]

Have you crashed or adjusted your twist throttle lately could be some bind in there. Your throttle should snap back not move slow.

[Kawadougie]

If you reach down and feel the top of your carb after your bike is warm, you will notice it gets fairly hot.  It's close to the pipe and the cylinder head.  The slide wouldn't do it all the time, but when it did, it was always at full throttle.   I tried replacing the throttle, cable and even a new slide.  The last time it happened my riding buddy and I took off the cap on the carb and found the slide was stuck at the top.  I poured some water on it to cool it down and it freed up.  My newer KX doesn't have this issue.  

[5dracing]

What about wrapping the pipe in this area with the ceramic cloth?

[John]

That's one nasty situation to be in.

On the same subject; I know Doordie has a snowmobile killer-switch-strap wrapped arond his arm when he rides. If the bike takes off by itself the engine is killed before Doordie hits the ground (not that I ever seen that happening).. That was not the case with my 125 who after a ride by itself eventually ended up submerged in a river...

//John