2003 KX65 won't idle and eventually dies

DaRooster

Member
Oct 8, 2005
49
0
Hey folks,

I am at wits end with my sons bike. It started developing probably last Sunday at practice. The bike develops a mean bog at idle to 1/4 throttle and you have to rev the s&*t out of it to keep it going. I've basically thrown every but the sink at it and have ran out of options.

It recently received a new top end this spring and has has around 3 hours I'd say on it. Today I's put a new plug in, new air filter in, repacked the silencer, changed needle positions both ways, adjusted the air screw, completely cleaned the carb and its innirds and put fresh gas in. I'm still stuck!! I don't have any other pilot or main jets to throw in just adjusting what I have. Also, its around 80 degrees here and I live near central Ohio (for altitude). If anyone and I mean anyone has any other suggestions please feel free to chime in.

Also, I've read all the jetting links and have one of Eric Gorrs guide books. I've read them front to back and haven't a clue what to do now!

Thanks,
Chad

Oh, BTW I am using 92 octane and Bel-Ray MC-1 32:1 mixture, if that helps.
 

rpm12505

~SPONSOR~
Sep 25, 2005
190
0
Next time it does it, roll up eric's book and smack it on the front fender screaming "BAD KX BAD". It always works for our RM :nod:
 

DaRooster

Member
Oct 8, 2005
49
0
Just a footnote to this subject. My son laid the bike down 2 times (one time pretty good on an off camber turn). My question is: could that allow the trans oil to slip into the crankcase that would be due to a failing crank seal?? Just trying to think of anything that might be the culprit.

Thanks,
Chad
 

DaRooster

Member
Oct 8, 2005
49
0
No, I stripped the carb, cleaned and replaced everything as it came off. When he laid it down, it was on the left side if that makes any difference or sense. I am thinking of tomorrow draining the trans oil and looking and verifying the crank seals to rule that out. Any other replies would be welcome.

Thanks,
Chad
 

DaRooster

Member
Oct 8, 2005
49
0
Problem solved, clogged pilot jet. Cleaned the outside but forgot to swab the center. Dummy me but I figured out anyways. That what was wrong with my bike too. It is what it is I guess. Thanks to all who replied.

Thanks,
Chad
 

bentbarz

Member
Dec 16, 2000
29
0
I am reviving Arnold thread here...

I have almost exactly the same story, including the crash, with the same level of frustration. The only difference is that I have too much fuel in the pilot circuit range as confirmed by the choke making it die even quicker. Runs great above the pilot circuit range. I have checked the float level, and while I wouldn't wager a large amount, I think it is right. Like any bike,if I lean it to about 30 degrees I get some fuel out the overflow tube.

I am starting to think electrical. There's spark, but there is the concern as to whether or not it is still there under load. My other thought is something in the top end, but it has been running well with no smoke or hard starts like you normally get. Exhaust is new as of Christmas and probably doesn't have more than 10 hrs, so I really doubt the packing.

What am I missing?
 

_JOE_

~SPONSOR~
May 10, 2007
4,697
3
Have you removed the carb and forced aerosol cleaner and compressed air through all the passages? You could have a clogged air passage causing it to run rich on the pilot.
 

bentbarz

Member
Dec 16, 2000
29
0
Found it.

I cleaned and recleaned the carb about four times.

I decided to drill deeper and found broke piston rings and as a result a dead cylinder too. Can't believe the thing ran like it did. New cylinder and top end on the way. Should be assembled Friday for some practice before the race Sunday.
 
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