old kx500 need help

[alexd]

i just put my dads old 1987 kx500 together he cracked the frame and it needed welded and never got to putting it back together it has been sitting for 15+ years but is it good condition any ways i got it all back together and started up relativaly easy after an attempted drift start then it just revs right up to full throttle i cleaned the carb with carb cleaner and lubed the throttle cable it all works good when the bike is off. he made me use a 15 year old old mix but new gas and carb is clean i cleaned it twice. messed up jets?? wont turn off till it runs outta gas

 

[spark250]

i just put my dads old 1987 kx500 together he cracked the frame and it needed welded and never got to putting it back together it has been sitting for 15+ years but is it good condition any ways i got it all back together and started up relativaly easy after an attempted drift start then it just revs right up to full throttle i cleaned the carb with carb cleaner and lubed the throttle cable it all works good when the bike is off. he made me use a 15 year old old mix but new gas and carb is clean i cleaned it twice. messed up jets?? wont turn off till it runs outta gas

Uhhhhh..... what? :whoa:

 

[2strokerfun]

Sounds like an air leak.
Check the rubber manifold the carb is attached to.
Then check the seal on the left side under the stator.
Seal might have dried up over time if it isn't the carb boot.
An air leak will lean your mixture and make the engine rev out of control.

 

[gwcrim]

Lots of KX500 junkies at kxriders.com.

 

[alexd]

i took the carb off checked the boot like you said 2stroker umm reeds all look good no air leaks cleaned the carb twice already any help please!

 

[whenfoxforks-ruled]

When it revs high and will not shut off, check the plug, wet or dry. Is the slide bottoming out all the way? Get an aftermarket kill switch also. When you clean the carb, that means removal of all the jets, remove all the tarnish and actually poke something through to clean it, do not scratch the inside. And do the same to all the passages. I think if its an airleak, it would not idle correctly, it would rev high and erratic. You will need to replace the float valve and seat if it comes out. Racing it gets replaced yearly, otherwise, when you have jetting/carb issues, replace it and save a headache!

 

[OriginalRider]

Could be the floats.Check with a dealer to get the correct position.Had the same problem with my 82 yz100j turned out to be the floats.