Author Topic: Getting the jet needle out of the throttle valve?  (Read 27122 times)

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Offline mustangfury

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Re: Getting the jet needle out of the throttle valve?
« Reply #15 on: April 15, 2010, 12:58:36 PM »
thanks guys!  I used an 8mm socket and it went on with a few taps of the plastic screw driver handle.  Worked like a charm!  Great suggestion.  Whoever had the bike before me had the jet needle set for the leanest setting.  I put the clip on the needle back at the middle notch and the bike runs like a whole new animal!  I live on a 1/4 acre piece of property but in first gear i just gave it about 1/2-3/4 throttle and it wheelied.  I think that solved that problem. thanks again!

Only problem left now is that i am getting even more oil spewing out of the exhaust.  I attached some pictures to give you an idea.  This was oil just from the bike idling for maybe 5 minutes or so.  After about 15 minutes of riding the whole back right underside of the tail will be black.  Also the swing are will literally have a stream of black running down it from the oil dripping out of the joint between the fatty pipe and the silencer pipe. any ideas on this would be great.

1993 KX 125

Offline Purpletj

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Re: Getting the jet needle out of the throttle valve?
« Reply #16 on: April 15, 2010, 01:27:29 PM »
Silicone is your friend. Apply at every joint including the head pipe. It wouldnt hurt to tear the silencer apart and repack it as well.
"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 #17 on: April 15, 2010, 05:37:45 PM »
  :-o
  Hhhmm.. Stang, if your crank seal is ok,  It looks like you may be a tad rich...
Have a look through this link:
http://www.maximausa.com/technical/oilmigration.html

 If you are sure your seals are good, the next thing I would start with is what kind of riding will you be doing primarily.
  Mx, recreational trail riding, dunes etc.
How hard and what level do you think you ride.
  What do you have as far as mods on the bike, and do you plan on using race fuel or pump.
What is your elevation and temps.
    The more info you have the better chance we have of getting you dialed in.
There is a team green jetting chart that has been really helpful for getting a starting point or baseline.

  http://www.teamgreennews.ca/techside_settings.html
   
If you are willing to spend a little time on research and maybe a few pilot & main jets we should be able to get you real close. 
   Tuck\o/   
« Last Edit: April 15, 2010, 06:11:21 PM by Friar-Tuck »
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Offline mustangfury

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Re: Getting the jet needle out of the throttle valve?
« Reply #18 on: April 15, 2010, 11:47:22 PM »
I don't know if the crank seal is ok.  Supposedly it had just been replaced when I purchased the bike, but you know how that can be.  What is the easiest way to check that? Is there a way i can check that without ripping the motor all apart?

I do more of trail type riding, usually sticking to the first three gears.  The only other riding i do is out on my uncles farm. 40 acres of open ground so then i go wide open with it.  Sometimes i like to just cruise around from point A to point B on the farm though, still pretty quick: transportation.  I would say i am in the middle of mx and recreational. 

I ride in elevation between 100 and 1000 feet at most and temps between 60 and 90 degrees. 

i use pump fuel 93 octane.

For mods, I have an fmf silencer, fmf fatty pipe, standard bore with wiseco piston, and vforce reed valves. 

I curently run 32:1 fuel:oil ratio with Bel Ray H1R.

My bike is a 1993 kx 125 J2
1993 KX 125

Offline Hillclimb#42

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Re: Getting the jet needle out of the throttle valve?
« Reply #19 on: April 16, 2010, 12:01:03 AM »
You can go to 50:1, Probably should. H1R is good at lower ratios. Silencer repack is also a good suggestion. I wouldn't change much. My 250 will throw some oil on the fender, when I'm ripping on it. Clean and silicone the rubber boot that joins the silencer to the pipe. I wouldn't change jetting because of oil on my fnder and swingarm. 

Offline Friar-Tuck

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Re: Getting the jet needle out of the throttle valve?
« Reply #20 on: April 16, 2010, 02:59:43 AM »

Spooge, assuming a lack of mechanical problems such as leaking crank seals or bad reeds, is caused by rich jetting.
  I'll come back in a bit with a longer explanation of my thoughts on that.
   Thank you Stang for hanging with me.  One more thing,
Do you know what you have for jetting (Main,pilot,needle and clip position presently)
    Another reason the spooge factor may be so high is running from point to point on the farm, the Combustion chamber, exhaust and pipe may not have gotten hot enough to burn off the oil. 
    I'll be back with more after I get our 5th grader off to school.
(yes I know your thinking, are you smarter than a 5th grader?......well ... :oops: no not really!)
    Tuck\o/
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Offline Hillclimb#42

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Re: Getting the jet needle out of the throttle valve?
« Reply #21 on: April 16, 2010, 03:12:33 AM »
 IMO, Tuck the spooge is unburnt oil. Hopefully two stroke oil. At 32:1 with the High Grade H1R, would be my 1st guess as something to alter for the desired result. Since the stuff is getting everywhere, I would guess the packing is saturated. I change jetting according to performance only, spooge can happen on any bike. If you are in the tight trails or putting for awhile, then hold it WFO for any length of time, you'll have some black on the fender. Sometimes the unburnt oil in the silencer will get to smokin' like its on fire, thats what its all about. It runs good, right ?

Offline mustangfury

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Re: Getting the jet needle out of the throttle valve?
« Reply #22 on: April 16, 2010, 03:26:39 AM »
I meant to write down the jet needle size.  I believe I remember a 2 marked on it. I have had pretty much everything apart on the bike and most of the bike settings were set at the manufacture default from the time i got it, so i believe the jet needle is probably stock for a PWK.  I do not know what the throttle or main jets are but i am pretty confident in saying they are stock.  I can double check all of this though.  The clip position i do know is right in the middle. I do not believe this is the problem, because if i put it one step leaner, the bike goes back to the previous problem.  The middle gives me the best performance.


IMO, Tuck the spooge is unburnt oil. Hopefully two stroke oil. At 32:1 with the High Grade H1R, would be my 1st guess as something to alter for the desired result. Since the stuff is getting everywhere, I would guess the packing is saturated. I change jetting according to performance only, spooge can happen on any bike. If you are in the tight trails or putting for awhile, then hold it WFO for any length of time, you'll have some black on the fender. Sometimes the unburnt oil in the silencer will get to smokin' like its on fire, thats what its all about. It runs good, right ?


That is pretty much exactly what happens.  When i hit the throttle hard it really shoots stuff out and leaves a puff of blue smoke behind.  The only thing is, i have repacked the silencer several times before and it just got soaked within a few minutes of riding and i was back to the same problem.  I was planning on repacking it again anyway, now that i adjusted the jetting.  The bike was running too lean at mid range.  Would running it too lean cause extra oil out the back?  I was thinking this could be it.  I am sure it is loaded with oil.  It just seems like it is putting out more oil than just some oil getting pulled out of the silencer.  Also, would the oil be coming out of the joint in the pipe if it was just the silencer?

Finally, yes it runs great! it's just the oil problem.  My only complaint is that it makes a mess.  Thanks guys

also, i have a feeling it is unburnt two stroke oil. I was using a honda oil and switched to the bel ray oil, hoping the honda stuff might have been junk or something, and I noticed the consistency of what was spitting out changed so i assume that it is the unburnt 2 stroke oil.  FYI:The bel ray oil definitely runs better.

BTW: That last picture i posted is the rubber cover of the governor assembly that runs into the exhaust valve. The oil is coming out of that rubber boot. I don't know if that has anything to do with the problem.
« Last Edit: April 16, 2010, 03:35:46 AM by mustangfury »
1993 KX 125

Offline Friar-Tuck

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Re: Getting the jet needle out of the throttle valve?
« Reply #23 on: April 16, 2010, 04:13:59 AM »
  I'll look up the stock jetting and get back with you.
  If you are happy with the way the bike is running then don't change anything.
I do agree with #42 if you have a chance you might re-pack the silencer as I'm pretty sure it's soaked.
   The next thing that usually follows is the packing falling apart and into and or through the pipe.
We could work through this if you like, just remember it will take time to clear out the whole system.

I wish I was smart enough to have written this all by my lonesome.."Chokey" or "Spanky" is the original author.  I have attempted to take some of the "sting" out of the paper. As it is not my intent to offend anyone, least of all a poor chap actually trying to find answers, and do what's right.

Chokey's post on the subject here: 3rd post down http://twostrokemotocross.com/forum/index.php/topic,59.msg2468.html#msg2468

 Spankys jetting guide:
http://www.kawasakimotorcycle.org/forum/kawasaki-motocross-offroad/17227-spankeys-jetting-guide-info-2-stroke-riders-must-have.html

Anyone that believes that spooge and plug fouling are caused by too much oil in their Pre-mix May have been misled.
    If you know how to jet, you can run any amount of oil you choose, and have absolutely zero spooge.
You may not be old enough to remember, however I never saw any drooling on any factory mx bike, or for that matter any factory race bikes. 

There is a prevailing myth that less oil is better. This simply isn't the case.
    While true,there isn't a magic "one-size-fits-all" mix ratio, and it is possible to use too much oil for your conditions, generally speaking, more oil is better, within certain limitations.

When an engine is jetted too rich, the excess fuel leeches heat from the combustion process, causing the combustion chamber temperatures to be too low to effectively burn the oil, or even completely burn all of the fuel. The result is spooge and deposits. The spooge is nothing more than unburned fuel and oil passing out the exhaust.
      It may leak from the exhaust flange at the head pipe/expansion chamber,the joint at the silencer to expansion chamber and right out the silencer tip onto your fender.  The exhaust valve may be fully engulfed as well as the silencer packing.
 A spooge problem, is a jetting problem. You don't get rid of the spooge by reducing the oil, you get rid of it by fixing the jetting. Correct jetting will produce an air/fuel ratio of about 14:1, which will produce combustion temperatures in the 6000F range and exhaust temperatures in the 1200F range. This will provide sufficient heat to consume the premix oil.
 And,by the way is where expansion chamber producers build their pipes to operate at.
           The same goes for plug fouling. Rich jetting does two things. First, it promotes incomplete combustion of the fuel and the oil due to reduced combustion temperatures. The incomplete combustion of the fuel and oil promotes deposit formation inside the engine. Second, rich jetting reduces the combustion temperatures, which in turn reduces the engines ability to burn off deposits. Combine increased deposit formation with reduced ability to burn off those deposits, and what do you get?
  Spooge,plug fouling and a carbon seized exhaust valve.

 Choosing a mix ratio based on the amount of oil your engine needs to provide sufficient protection and adequate ring seal.
    The common misconception is that mix ratios are "one-size-fits-all", when in fact nothing could be farther from the truth.The amount of oil that is correct for one rider on his bike may not be enough oil for another rider/bike, or it may be too much oil.
           It all depends on engine displacement, riding style, and how hard you push the engine.
  A trail rider on a 500 that never reams the bike out (Me!)is probably fine on a mix of 50:1, where a super-fast up-and-coming future pro that screams an 85 'till the dogs howl the entire time he's on the track might not get a full day of racing out of an engine on less than 30:1.
Your engine's oil needs are determined by displacement, rev range, and the loads you put on it.

                When you shut your engine down and let it sit, much of the oil drains down into the crankcase and forms a puddle in the bottom. The depth of this puddle is your indicator of whether you are running the correct amount of oil for your engine's needs. Ideally, you want this puddle to be between 1/8 and 1/4 inch. If it's less, you need more oil in your mix. If it's more, you are running more oil than you need for your conditions.

With that said, to have that amount of residual oil in the crankcase at 50:1
     (a ratio made popular by magazines and oil bottles), you can't be riding very hard, or your bike is jetted richer than necessary simply to deliver enough oil.
   I arrived at 40: for my bike with my riding style because that is the amount that gives me the proper amount of residual build-up, good ring seal,and a small peace of mind factor and all with out the spooge.
    Small-bore engines require greater oil concentrations than larger engines to achieve the proper amount of residual build-up, because they rev higher and have higher intake velocities. Along the same lines, someone that pushes the engine harder, and keeps the revs higher, also needs to use higher oil concentrations to achieve the proper residual build-up.

     To understand why the mix ratio is so important, you have to understand what happens to the oil in your fuel when it goes into the engine. While the oil is still suspended in the liquid gasoline, it can not lubricate anything.
   It has to precipitate on to or into something, just like water on the outside of a cold glass in warm weather.
  When the gasoline enters the engine, it evaporates, dropping the oil out of suspension.   
      Now that the oil is free, it can lubricate the engine.
 The oil mist is distributed throughout the engine by the spinning crankshaft and the moving air currents to coat all the internal surfaces.
    The oil moves through a two-stroke along with the fuel, true; but at a much slower rate than people think.
 It can take 90 minutes or more for the oil migration through a two-stroke to result in a complete oil exchange on a slow trail ride, and even as much as 5 minutes for a full-throttle 20 minute moto.

The oil eventually makes it into the combustion chamber, where it is either burned, or passes out the exhaust. If the combustion chamber temps are too low, such as in an engine that is jetted too rich, the oil doesn't burn completely. Instead, some of it hardens into deposits in the combustion chamber, on the piston, and on the power valve assembly.
  The rest becomes the dreaded "spooge". The key to all of this working in harmony is to jet the bike lean enough to achieve a high enough combustion chamber temperature to burn the oil, but also still be able to supply enough oil to protect the engine.
           If you use enough oil, you can jet the bike at it's optimum without starving the engine of oil, and have excellent power, with minimal deposits and spooge. At 50:1 in a small-bore engine, you simply can't jet very lean without risking a seized engine due to oil starvation.

The bottom line?
 Choose a mix ratio that is adequate for your needs, and jet accordingly.
 You don't remedy plug fouling and spooge by adjusting your mix ratio alone,
however it does  play a part in tuning your engine, to your riding style & conditions. 

These are an interesting read that also supports  "more oil is better" claim.

http://www.bridgestonemotorcycle.com...oilpremix6.pdf

And this is a good article as well:

http://www.maximausa.com/technical/l...summer2001.pdf
« Last Edit: April 16, 2010, 04:39:20 AM by Friar-Tuck »
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Offline mustangfury

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Re: Getting the jet needle out of the throttle valve?
« Reply #24 on: April 16, 2010, 04:31:53 AM »
in order to check for the amount of oil in the crank case does that mean pulling the cylinder?  Also, I don't want to lean out the mixture if something else is the problem. I don't want to cause engine damage. I know i have other 2 stroke engines that i have run on more oil then they are supposed to have and they don't smoke.  I agree that more oil is better to the effect of more lubrication.  The point i see at which you have too much is when it kills performance or is saturated beyond reason (maybe my case).  That was a good article.

When you say don't change anything, do you think i should just live with the oil problem and enjoy the performance?

Just looking at it, you can actually see the oil spitting smoke puff on my profile picture.  that little puff of blue is it.
« Last Edit: April 16, 2010, 04:48:10 AM by mustangfury »
1993 KX 125

Offline Friar-Tuck

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Re: Getting the jet needle out of the throttle valve?
« Reply #25 on: April 16, 2010, 05:01:06 AM »
Well, I certainly don't want to cause you any harm.
  You can clean up the problem without tearing your engine down.
    I have never burnt up an engine with stock jetting, or moving one jet at a time up or down.   You will get into trouble dialing in a bike on a 85 deg summer day and fire up the bike and rip around   on say a 40 degree day mid winter without changing anything.
   I am a fair weather rider myself.   I'm wracked with Arthritis and degenerative joint stuff, however I do swap things out for spring/fall and summer.   Funny thing is the more you work on the bike the faster things go.
  All this entails now is two pilots 50 summer 55 spring/fall.   two mains 162 summer and 168 spring/ fall
I just swapped needles so I'm still experimenting  and of course the air screw depends on current weather.
  (I use this for warmer cooler humid dry throughout the year.)

 I am afraid your silencer is soaked, I can find a thread on that if you need. Packing itself is about $15.00 or so.
   Cleaning out the exhaust valve and the expansion chamber, that's  gasket's and some other consumeables. If you don't need re-building wait 'till you do.  Get the old girl running the way you like and then worry about that.
    You certainly won't hurt anything running in your present state unless the exhaust valve gets gummed/carboned up.  If you can move the assembly in and out smoothly without strongarming it your ok.

    Spend a bit more time snooping around before you make a descision on where to start first or at all.
It won't cost anything and the more information you have the better decision you can make.   :wink:
  Tuck\o/     
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Offline mustangfury

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Re: Getting the jet needle out of the throttle valve?
« Reply #26 on: April 16, 2010, 05:12:44 AM »
How easy should the exhaust valve move in and out. i had that out about a year ago and i re oiled it and cleaned it up. there wasn't any carbon buildup that i could see at all.  It looked like it didn't need it but i figured a good cleaning wouldn't hurt while i was at it.  Now, opening and closing it by pulling on the governor is pretty difficult.  I can do it by hand but it takes a little strength to move it.  is that normal?
1993 KX 125

Offline Friar-Tuck

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Re: Getting the jet needle out of the throttle valve?
« Reply #27 on: April 16, 2010, 06:06:54 AM »
If you disconnect the arm that pulls/returns  the rod  it shouldn't take more than a 8oz. or so of push pull to move in and out. 
Think of holding a can of soup in your hand.  The effort it takes to move the can up and down should be adequate to move the valve.
  Here's what I found on jetting specs:
  Oem  160 main                         FMF site 158 Main              (and using Bel Ray @32:1 )
           52 pilot                                        52 Pilot
       N1AL Needle                                     Stock needle
          3rd clip                                        3rd clip position   
         11/2 turns out on the A.S.                11/2 turns out

 You can be pretty safe on the FMF suggestions as they surely don't want you getting a new engine account they got your bike melted down.   This should be a good place to start.  you can replace the main with a 6mm socket by removing the 17mm plug on the bottom of the carb.
   Cut the bottom off a water bottle to catch the fuel from the carb bowl.
Having a clean air filter and fresh fuel also helps.
  Making one change at a time and keeping a log/notebook is also handy.   
If you can swing a service manual or clymer specific for your bike it will make things easier for you and they also have alot of other info to boot.     
  Tuck\o/
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Offline mustangfury

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Re: Getting the jet needle out of the throttle valve?
« Reply #28 on: April 16, 2010, 09:11:13 AM »
yeah i have a clymer manual i have been referencing. It has a lot of good stuff.  I'll check the jets and see what size they are after i repack the silencer, and i'll go from there.

thanks all for your help. I'll let you know how things go.
1993 KX 125

Offline bigbellybob

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Re: Getting the jet needle out of the throttle valve?
« Reply #29 on: April 16, 2010, 09:29:26 AM »
if you suspect gear oil getting sucked in past a bad crank seal you can do a simple test. with the bike running lay it to the left/ ignition side and give it some good healthy raps. note the amount of smoke and spooge. then lay the bike to the right / kicker side and give it some more healthy raps. putting the bike on the right side will put the seal in the oil and if its sucking some in you should see the difference in smoke out the exhaust. o and the gear box will need to be at the correct level before trying this. and have her up to temp. its impossible to properly evaluate jetting and such if the bike isn't completely up to temp.
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