KX Riders

Maintenance & Technical => KX500 Original => Topic started by: bjohn07 on January 30, 2013, 10:05:15 AM

Title: help with idle adjustment
Post by: bjohn07 on January 30, 2013, 10:05:15 AM
so im not able to adjust idle at all, screw in or out has no change. if i loosen or tighten the upper part of the cable at the throttle idle will adjust  but i get surging.  any ideas. 
Title: Re: help with idle adjustment
Post by: sandblaster on January 30, 2013, 10:12:18 AM
What are you adjusting, pilot or stop screw?

(http://i644.photobucket.com/albums/uu165/oemcycle/KX500AF%20PROJECT/AIRSCREW-1.jpg)
Title: Re: help with idle adjustment
Post by: bjohn07 on January 30, 2013, 10:20:51 AM
What are you adjusting, pilot or stop screw?

(http://i644.photobucket.com/albums/uu165/oemcycle/KX500AF%20PROJECT/AIRSCREW-1.jpg)

throttle stop is the one im adjusting.  could a lean pilot jet be the cause of not being able to set idle.
Title: Re: help with idle adjustment
Post by: cmotodad on January 30, 2013, 12:28:20 PM
You say there is no change. Does it take a little longer to die with the screw in?
Title: Re: help with idle adjustment
Post by: bjohn07 on January 30, 2013, 12:34:03 PM
no.  about the same. bike will run on its own and idle will slowly die down. after about 15 seconds the bike stalls.  so ive just been giving it gas to keep it form stalling.  im running a 58 pilot jet in it.     only way i can get the bike to idle is to tighten up the slack on the cable itself.  but i know thats not the right way of doing it. 
Title: Re: help with idle adjustment
Post by: cmotodad on January 30, 2013, 01:15:52 PM
How much do you need to adjust the throttle cable? Quite a bit? Just a little? Did you pull the idle adjustment screw to check the length? Maybe worn or tip damaged.
Title: Re: help with idle adjustment
Post by: bjohn07 on January 30, 2013, 01:57:15 PM
quite a bit.  once i adjust it to where it needs to be to keep the bike at an idle the cable adjuster screw is prob  3/4 the way or a little more out.  yes i unscrewed the idle screw all the way to look at it.  didnt measure. but the tip is nice and pointy, not flat or rounded.  what is the length suppossed to be on that?    i did notice that when i let the bike run with the choke on,  once it is a little warm after about 3 minutes or so i dont need to mess with the throttle any more to keep it going.  as long as the choke is on the bike idles but high.  around 1600-1800. ( the  throttle cable adjuster was turned in all the way at this time so im sure that it had no effect on this)
Title: Re: help with idle adjustment
Post by: cmotodad on January 30, 2013, 05:23:36 PM
Sounds like it could be lean on the pilot if it idles with the choke. How does it run off idle under load? Does it bog or hesitate then pick up rpm's?
Title: Re: help with idle adjustment
Post by: bjohn07 on January 30, 2013, 06:51:36 PM
Sounds like it could be lean on the pilot if it idles with the choke. How does it run off idle under load? Does it bog or hesitate then pick up rpm's?

off idle under load?  as in taking off outa first?  it hesitates a little bit. im just going off sound of engine but id say its from 1400-1800 and then it smooths out.   
Title: Re: help with idle adjustment
Post by: cmotodad on January 31, 2013, 12:16:28 AM
I would try a richer pilot jet. It does not gurgle and feel like it wants to load up, right?
Title: Re: help with idle adjustment
Post by: Hillclimb#42 on January 31, 2013, 12:46:35 AM
did you fatten up air screw? as cold as it is here, it would be lean. air screw would likely need to be all the way in, or like mentioned, increase the pilot size. Adjusting the cable to get an idle is bad, really bad. It can make the bike rev, when you turn the bars, or can even caus the motor to rev out of control just sitting there. the slide closing helps kill the motor in the event of an air leak or ring heating up during seating. Also could be  slide wear where the idle screw makes contact. Im guessing freakin cold is makin the k5 unhappy...
Title: Re: help with idle adjustment
Post by: bjohn07 on January 31, 2013, 03:43:36 AM
Ill try to fatten up the air screw today. If not im hoping apex stocks the pilot jets
Title: Re: help with idle adjustment
Post by: bjohn07 on January 31, 2013, 10:54:22 AM
air screw didnt work. so i picked up a 62 pilot.  once it was warm it ran a little better than before but still wont idle.   :-(  not sure where to go from here.  dirt bike carbs are way harder for me to grasp than good ol 4 barrels.
Title: Re: help with idle adjustment
Post by: sandblaster on January 31, 2013, 11:06:57 AM
This article I wrote might help you learn a bit about your carb.
http://www.oem-cycle.com/forum/viewtopic.php?f=5&t=109 (http://www.oem-cycle.com/forum/viewtopic.php?f=5&t=109)
If you find anything useful, or confusing, let me know.
Title: Re: help with idle adjustment
Post by: Friar-Tuck on January 31, 2013, 04:27:32 PM
 How does the slide look? 
The link has a pic of what the slide will look like when the chrome has flaked or
worn off.  (you have to scroll down a tad)   
 This will play havoc with trying to get that carb tuned.   
     (Kind of what happens when  throttle shafts are worn/worn out.)

http://www.dirtrider.net/forums3/showthread.php?threadid=172951

  Tuck\o/
Title: Re: help with idle adjustment
Post by: bjohn07 on January 31, 2013, 04:32:46 PM
How does the slide look? 
The link has a pic of what the slide will look like when the chrome has flaked or
worn off.  (you have to scroll down a tad)   
 This will play havoc with trying to get that carb tuned.   
     (Kind of what happens when  throttle shafts are worn/worn out.)

http://www.dirtrider.net/forums3/showthread.php?threadid=172951

  Tuck\o/
looks nothing like that one.  looks pretty good to me.  some wear marks but no deep gouges or nicks or anything like that.
Title: Re: help with idle adjustment
Post by: bjohn07 on January 31, 2013, 04:34:35 PM
might be the weather is a little to cold for me to get it right.  its been 45 or lower here.  gonna wait till it gets to at least 65 till i try again.  and i just ordered a new air filter.  the one that came with it looked old and worn even after i cleaned it.   
Title: Re: help with idle adjustment
Post by: Friar-Tuck on January 31, 2013, 04:58:39 PM
 Well Rats,
 There are a few brave souls racing out there on frozen lakes, so it can be done, I guess.
    There is a bunch of KX500 info posted here: http://media.beta.photobucket.com/user/Friar-Tuck/profile
You do have to snoop around the site some.
 and some more Here: http://www.kxriders.com/coppermine/thumbnails.php?album=lastup&cat=1&page=2

  Hang in there,  You'll get her there.
  Tuck\o/
Title: Re: help with idle adjustment
Post by: bjohn07 on February 04, 2013, 12:38:43 PM
i think im really close.   this bike takes along time to warm up, like 15 minutes (its in the 50s here) but once its warm i finally got it to idle on its own, the idle screw in pretty much all the way in.  and the idle/air mixture screw is 3 turns out, does this mean i need to richen up my pilot jet?  pulled the plug to check it out after riding, got wot a few times in 3rd and fourth.  plug is wet, not soaked and black, but wet, ceramic piece on plug is still normal color only soaked.  should i come down on my main jet?           
Title: Re: help with idle adjustment
Post by: Friar-Tuck on February 04, 2013, 01:11:02 PM
 Ideally you want 2 turns out on your air screw, this will give you some adjustment either way for daily weather/temp & elevation changes.   
    The air screw regulates the amount of air added (or taken away) from the pilot circuit.
( see second diagram on page http://www.kxriders.com/coppermine/displayimage.php?album=lastup&cat=1&pos=52 )
   If your a.s. is three turns out from seated, you are "leaning out" the  amount of fuel your current pilot jet
is feeding your engine.     Dropping one size pilot jet  should require you to "turn in" the current position of the A.S.
  to hopefully about..... two turns out!  :-D   

 
Title: Re: help with idle adjustment
Post by: bjohn07 on February 04, 2013, 01:16:06 PM
good thing i asked.  i was thinking it was reversed and i was planning on upping the jet.     so down a size on my pilot is the nxt move.   let you guys know tomorrow evening if it works.  as long as i get out of work on time.   
Title: Re: help with idle adjustment
Post by: Friar-Tuck on February 04, 2013, 01:28:53 PM
Check this out :  http://beta.photobucket.com/images/kx500%20owners%20man

Look at the chart for around 9600' and around 50 deg (F)  you use a correction factor of about .95

 Does any of that stuff make sense?
 T\o/
Title: Re: help with idle adjustment
Post by: bjohn07 on February 04, 2013, 03:11:51 PM
sorry.  makes no sense to me.   :?  having some trouble understanding that.  that is the same chart in the owners manual in the carb tuning section?
Title: Re: help with idle adjustment
Post by: bjohn07 on February 04, 2013, 03:20:00 PM
Check this out :  http://beta.photobucket.com/images/kx500%20owners%20man

Look at the chart for around 9600' and around 50 deg (F)  you use a correction factor of about .95

 Does any of that stuff make sense?
 T\o/
okay did some searching and found this.http://justkdx.dirtrider.net/printcarbtuning.html  helped me get a grasp on the correction factor. 
Title: Re: help with idle adjustment
Post by: Friar-Tuck on February 04, 2013, 04:52:17 PM
 Hang in there Man,  You'll get her runnin' like a scaulded Dawg.   :-D   
     Tuck\o/
Title: Re: help with idle adjustment
Post by: bjohn07 on February 06, 2013, 04:34:59 PM
so i think this has something to do with the bad idle.  been searching and all says your not supposed to see the light.  i already tried flipping them and the gap just opened up a little more.   
Title: Re: help with idle adjustment
Post by: Friar-Tuck on February 06, 2013, 05:24:18 PM
 Yep, the shin bone connected to the ankle bone, well, you know..
   Most every jetting guide will ask if you've already gone through the bike eliminating anything that could throw a curve at you.     I apologize for not asking all the preliminary stuff :oops:   
   Well, Better to find this now than after a month of "Try this or that".  :-D
After you decide on reeds and possibly the spacer maybe we could take it from the top?
  Tuck\o/
Title: Re: help with idle adjustment
Post by: bjohn07 on February 06, 2013, 05:42:51 PM
Yep, the shin bone connected to the ankle bone, well, you know..
   Most every jetting guide will ask if you've already gone through the bike eliminating anything that could throw a curve at you.     I apologize for not asking all the preliminary stuff :oops:   
   Well, Better to find this now than after a month of "Try this or that".  :-D
After you decide on reeds and possibly the spacer maybe we could take it from the top?
  Tuck\o/

not anyones fault but mine.  i should have known better but i am pretty new to the 2 stroke.  oh well.  live and learn.   thanks for everyones help so far.