Author Topic: Getting the jet needle out of the throttle valve?  (Read 27151 times)

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Offline mustangfury

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Getting the jet needle out of the throttle valve?
« on: April 12, 2010, 04:39:18 AM »
I am having a problem with my bike bogging out in the mid range.  It goes well up till about 1/4 throttle, boggs up to speed slowly from 1/4 to 3/4, then at 3/4 tears down the road like there is no tomorrow.  I am also having an excess of oil that spits out the silencer when i wind it out.  I think it might be the oil that isn't burning completely when the engine is bogging out.  I have done one thing at a time trying for results but nothing has delivered yet. I have cleaned the air filter, checked compression, checked reed valves, and a few other things.  The range of lacking performance seems to suggest it has to do with the jet needle being out of adjustment or the wrong size. I am going to try an move the clip either up or down on the jet needle but i can't seem to get the cable screw out of the throttle valve. The bike came with an fmf fatty and silencer.  It also has Vforce Reed Valves.  I run a 32:1 mixture which kaw. recommends using Bel Ray H1R.

My question is:  how do you get the cable screw out of the throttle valve assembly? I tried to get some needle nose pliers in there but all it seems to want to do is tear up the screw. 

Any suggestions on how to get it out besides drilling it or doing something that will require its replacement. Any suggestions on my general problem are welcome too.

Thanks
1993 KX 125

Offline blueoval

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Re: Getting the jet needle out of the throttle valve?
« Reply #1 on: April 12, 2010, 05:22:47 AM »
mustangfury, what part on this diagram are you having difficulty with? 

http://www.mxsouth.com/keihin/keihin-complete-carburetors-diagram-parts-list-of-pwk33.htm
If some is good, and more is better, then too much is JUST RIGHT!  B.O.

Offline Hillclimb#42

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Re: Getting the jet needle out of the throttle valve?
« Reply #2 on: April 12, 2010, 05:31:48 AM »
Finally a question that I get. The carb's upper chamber all unscrews, the little brass screw stays. You can release the clamps and turn the carb towards you a little, or pull the whole carb out. The whole top cap of the carb comes off and the slide will still be connected to the cable. The top cap should come off with your hand twisting it. Smash the spring that you will find between the slide and the cap, all the way compressed. hold the spring compressed to the lid of the carb. push the slide toward the cap for some cable slack and with a little jockeying the cable will come free of its notch.
 If you look into the top of the slide, you will see a 6mm nut. That holds the needle in the slide. remove the nut and you will find the needle with a circlip stuck in one of 5 grooves. That clip is very hard to find if it shoots off there, so be careful. I lay it flat on a countertop and push the needle down while covering the clip with my hand, flip it over and snap the needle into the clip.
  Moving the clip up one position will lean the mixture in mid range by lowering the needle into the hole, thereby restricting fuel flow a little bit.

  When you put it back together, insert the needle and fasten with the 6mm nut, you have to again, smash the spring to the lid, then get the cable into its notch, then align the little plastic deal that keeps the cable from coming out of that notch. Make sure the throttle spring goes all the way down. Drop the slide back in there and screw the cap back on.

If this is the first time, you have been in the carb, it would be a good idea to pull it out all of the way and look it over for dirt and debris, or wear. Also good to note what jets are in it, and clip position, for future reference. I always snap the throttle a few times to make 100% sure that its working properly before starting it back up after messing with it, too.
« Last Edit: April 12, 2010, 05:35:31 AM by Hillclimb#42 »

Offline mustangfury

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Re: Getting the jet needle out of the throttle valve?
« Reply #3 on: April 12, 2010, 09:28:43 AM »
mustangfury, what part on this diagram are you having difficulty with? 

http://www.mxsouth.com/keihin/keihin-complete-carburetors-diagram-parts-list-of-pwk33.htm

I was refering to number 14 as the cable screw and was wondering how to grip it to get it out.

Finally a question that I get. The carb's upper chamber all unscrews, the little brass screw stays. You can release the clamps and turn the carb towards you a little, or pull the whole carb out. The whole top cap of the carb comes off and the slide will still be connected to the cable. The top cap should come off with your hand twisting it. Smash the spring that you will find between the slide and the cap, all the way compressed. hold the spring compressed to the lid of the carb. push the slide toward the cap for some cable slack and with a little jockeying the cable will come free of its notch.
 If you look into the top of the slide, you will see a 6mm nut. That holds the needle in the slide. remove the nut and you will find the needle with a circlip stuck in one of 5 grooves. That clip is very hard to find if it shoots off there, so be careful. I lay it flat on a countertop and push the needle down while covering the clip with my hand, flip it over and snap the needle into the clip.
  Moving the clip up one position will lean the mixture in mid range by lowering the needle into the hole, thereby restricting fuel flow a little bit.

  When you put it back together, insert the needle and fasten with the 6mm nut, you have to again, smash the spring to the lid, then get the cable into its notch, then align the little plastic deal that keeps the cable from coming out of that notch. Make sure the throttle spring goes all the way down. Drop the slide back in there and screw the cap back on.

If this is the first time, you have been in the carb, it would be a good idea to pull it out all of the way and look it over for dirt and debris, or wear. Also good to note what jets are in it, and clip position, for future reference. I always snap the throttle a few times to make 100% sure that its working properly before starting it back up after messing with it, too.

I've had the carb apart several times for cleanings so i'm familiar with that aspect of it.  That was the first thing i did in regards to the problem.  I checked the float and made sure the float needle was working properly.  I have gotten as far as getting the cable out of the assembly but the cable holder screw wont  break loose and i think it is just because i cannot grip it well.  There is no hex nut on my carb.  According to diagrams i have looked at similar to the one posted by blueoval, it is just the cable holder that screws in.  I don't know if i am using a different carb than yours.  it is a pwk keihin carb.


thanks for the replies
1993 KX 125

Offline Friar-Tuck

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Re: Getting the jet needle out of the throttle valve?
« Reply #4 on: April 12, 2010, 10:45:16 AM »
Does this help?
  You might drop some penetrating oil on it overnight.   I have seen the 6mm stripped/rounded.  There are a few options I can think of if it is stripped.
   Needle nose vice grips.
 If you have a dremmel and a small cutting burr you can carve across the the top and put a slot for a standard blade screwdriver.
 If that doesn't get it a reverse drill bit might.   The last resort  for me would be an easy out in the hole the reverse drill bit made.
 








« Last Edit: April 12, 2010, 04:52:38 PM by Friar-Tuck »
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Offline Hillclimb#42

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Re: Getting the jet needle out of the throttle valve?
« Reply #5 on: April 12, 2010, 02:35:29 PM »
Ahh, I thought you were working on the cable holder on top of the carb. Thats it, that is a taken off with a 6mm deep well socket on my bikes. didn't know there was different ones

Offline Friar-Tuck

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Re: Getting the jet needle out of the throttle valve?
« Reply #6 on: April 12, 2010, 04:36:49 PM »
 Rats...I just put those pics up a few hrs. ago.... :x 
  Nevermind gott 'er fixed up...
« Last Edit: April 13, 2010, 05:18:40 PM by Friar-Tuck »
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Offline Hillclimb#42

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Re: Getting the jet needle out of the throttle valve?
« Reply #7 on: April 12, 2010, 11:27:21 PM »
Friar is the living schematic. Thanks, Tuck.

Offline mustangfury

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Re: Getting the jet needle out of the throttle valve?
« Reply #8 on: April 13, 2010, 04:02:23 AM »
Yeah the 6mm is definitely gone.  It is so bad i couldn't even tell there used to be one.  whoever had the bike before must have screwed it up.  I was thinking about doing the dremel idea myself. I don't like cutting stuff up if i dont have to though.  I tried needle nose vice grips already but it still wouldn't budge. Some of that may have to do with the fact i can't really get a good grip on it with them.  it is so torn up.  I will put some penetrating oil on it and try the needle nose/ vice grips one more time then the dremel idea.  I'll let you know how it goes.

thanks.
1993 KX 125

Offline Friar-Tuck

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Re: Getting the jet needle out of the throttle valve?
« Reply #9 on: April 13, 2010, 08:38:07 AM »
 You're more than welcome & Good luck...
It may not have been that particular Piece I've fought with, but been there got the T shirt... :|

  #42 if you knew how long it takes to get the simplest thing accomplished around here you'd put it on SNL..
If you Cross The Simpsons and Gilligans Island you'd be pretty close to seeing what it's like in day my Life. :-o :lol: 
   Tuck\o/
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Offline Purpletj

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Re: Getting the jet needle out of the throttle valve?
« Reply #10 on: April 13, 2010, 02:11:41 PM »
Yeah the 6mm is definitely gone.  It is so bad i couldn't even tell there used to be one.  whoever had the bike before must have screwed it up.  I was thinking about doing the dremel idea myself. I don't like cutting stuff up if i dont have to though.  I tried needle nose vice grips already but it still wouldn't budge. Some of that may have to do with the fact i can't really get a good grip on it with them.  it is so torn up.  I will put some penetrating oil on it and try the needle nose/ vice grips one more time then the dremel idea.  I'll let you know how it goes.

thanks.

I had the same problem. Dont cut it with the dremel. A flat blade screw driver will just break the cheap metal. Stay away from the needle nose vice grips too. This cost me $70. I had to buy a new throttle slide. The only other option and the one that work for me is to get a 5/16 or 8 mm six point socket on your nut driver and force it on the shoulder beneath the 6mm. It wont go on easy. You may have to tap it a few times. We use to use this method to get locking lug nuts off car wheels, when the key had been lost.  I will use a photo from above to show the shoulder im talking about.
"When you sit with a nice girl for two hours, it seems like two minutes. When you sit on a hot stove for two minutes, it seems like two hours. That's relativity." -- Albert Einstein

Offline Friar-Tuck

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Re: Getting the jet needle out of the throttle valve?
« Reply #11 on: April 13, 2010, 05:21:52 PM »
 Ther ya go PJ,
 Did the same thing on the lost lug nut key and never crossed my mind to use that here... :?
   Tuck\o/
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Offline mustangfury

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Re: Getting the jet needle out of the throttle valve?
« Reply #12 on: April 13, 2010, 11:35:46 PM »
sweet.  That sounds like a good idea.  I did notice the vice grips wouldn't grip it too well mainly because the metal was so soft.  I never got time to dremel it yet so i'm probably still good to go.  I will definitely give this one a go.  Just for clarification, do you actually force the socket onto the round part, kind of cutting into it along its outer edge?  Is that the idea?
1993 KX 125

Offline Friar-Tuck

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Re: Getting the jet needle out of the throttle valve?
« Reply #13 on: April 14, 2010, 05:46:17 AM »
 Yep, You may have a better fit with an SAE socket, whatever looks close. It may require a good "rap" to get the socket to cut the cap, so be careful you don't damage the slide.  That may not sound easy, however a new slide is around $60.00 and that won't come with the little cap your working on getting out right now...
  Tuck\o/
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Offline Purpletj

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Re: Getting the jet needle out of the throttle valve?
« Reply #14 on: April 14, 2010, 02:07:09 PM »
I believe the socket I used was a 5/16. It wont take much to tap it on. I used i big screwdriver and used the plastic handle end  so I wouldnt mess up the throttle slide. 2 or 3 taps and will be on there.
"When you sit with a nice girl for two hours, it seems like two minutes. When you sit on a hot stove for two minutes, it seems like two hours. That's relativity." -- Albert Einstein