3/4 out airscrew too lean pilot?

[flynbryan]

Guys, I'm working with an older (2000) kx125 that I'm trying to work the bugs out of. I have been searching the archives here and have found that there were updates to the stock jetting to improve bottom-end from the factory. Referencing this thread *Link* --> ( 2000 Kx125 jetting ) and this thread as well as the original letter with the updated jetting specs recommend that I run a #40 pilot jet.

I currently am running the stock #45 and it seems to run best at 1_1/2 turns out to 2 turns out. I attempted to switch out the #45 for the supplied #40 the other day, but had to crank in my air screw to only 3/4 of a turn to get rid of the bog I would get when whacking the throttle at idle. Now from all the info I've gained in the past 3/4 of a turn dictates that I should be staying with the stock #45. Am I correct in thinking this? I was attempting to get rid of the spooge I'm getting from the tail pipe right now, but do not want to run too lean of a pilot to accomplish it. I know this is now an older bike, but can any offer any assistance?

 

[2strokerfun]

Keihin or Mikuni?? If it's a Keihin, you can go to a 42 pilot.
A little spooge is OK, though. I really don't think going from 45 to 40 pilot is going to lean it enough to damage your engine.

 

[flynbryan]

Sorry, the carb is a PWK Keihin. Bike seems to run well and I really don't have any complaints. Since the factory claimed that this jetting combo would yield better results and I was getting some spooge I figured I would give it a whirl.

 

[BigRedAF]

If it runs good at 1.5 - 2.0 no worries, that is well with in the range. As summer approaches and temps go up you may consider the 42.

The splodge could be caused from the oil type you are running. For example, if you run a castor based oil and putt around in the woods you will get splodge. Petroleum and synthetic oils burn cleaner.

How's the plug color after a hard ride?

Dark?

If so drop the main one or raise the clip one groove. Only try one at a time and ride some more. Based on your brief up top I think your pilot is fine. If your set on trying the 42 you can expect to set the air screw out less than 2 turns. It sounds like you understand that...

 

[flynbryan]

I was wondering if my pre-mix could be the possible culprit. I use Yamalube 2R. Its a semi-synthetic and I spend my time in the woods. Though I do have opertunities to open it up and do so whenever I get the chance, there is ALOT of time that I spend in the low-rpm range.

As for the rest of the jetting range, I feel I have a handle on that. I was just attempting to limit my spooge and possibly improve bottom-end performance. I do understand though that its a 125 and really has very little performance in that realm.

 

[AV8R]

If it was mine I would use the #40 at 3/4 turn on the air screw to be able to accomodate the rise in temperature as the day progresses.
Unless 3/4 turn out was only on a moderately cold day and you plan on riding on colder days.
The only real penalty for running the pilot too lean is the bog engine damage is not a factor on that circuit. The 40 would give you the flexability to lean it out to try to eleminate the spooge.
The spooge may be coming from your needle clip position also. Or the needle taper is to rich, you could try a leaner needle.

 

[Chili]

The spooge is not caused by the Yamalube 2R, we've run that in all our 2 strokes for the last five years and once jetted correctly they run really clean.

 

[flynbryan]

Needle clip position from the factory was the 3rd notch from the top. I currently have it at the 2nd notch from the top as thats what Kawasaki recommend in the update letter the previous owner was sent. In that letter they also sent the #40 pilot jet and a 42 power jet. I'm pretty sure the power jet is in, but have not checked. I'm curious to give the #40 a try. I guess I need to get out and actually RIDE with the 40 pilot in and see how it works. I was just scared to put too lean of a jet in there.

 

[Chili]

I'm no expert but I don't believe you could go so lean on the pilot as to cause damage, it would just run poorly.

 

[flynbryan]

This would be the correct circuit to attack to fight my spooge problem since I spend so much time in the lower rpms correct?

 

[AV8R]

This bike has a power jet? You could lean that as well but leave that as the last resort.
If it is a Keihin PWK PJ then the power jet is feeding fuel to the engine all the time until very high RPMs at which point it shuts off and the main jet is in control.
Don't worry about going too lean on the pilot, not a problem for the engine just bad performance.
I'm guessing it is a combination of pilot and needle. work those two areas. Try raising the clip one more notch. If it bogs in the mid range then that is too lean.
Check the power jet size and see if anyone has put in a lorger than stock jet there.

 

[BigRedAF]

The spooge is not caused by the Yamalube 2R, we've run that in all our 2 strokes for the last five years and once jetted correctly they run really clean.

I agree. I've used Yamalube-R in YZ's and CR's in the past with no problems at 32:1. Jetting is the key to all that troubles you.

 

[2strokerfun]

This would be the correct circuit to attack to fight my spooge problem since I spend so much time in the lower rpms correct?

Probably not. Even at low RPMs, you are rarely on the pilot circuit alone when riding. The pilot contributes about 5 percent or less of total jetting across the board and probably isn't contributing a lot towards your spooge, unless it just blubbers and dies whenever you let off the gas.

 

[whenfoxforks-ruled]

Power jet, pilot, needle clip, needle then main. Spooge you can not jet around points straight to mechanical issues. A little spooge is not all right, epa hazard! What does the plug look like?

 

[flynbryan]

Power jet, pilot, needle clip, needle then main. Spooge you can not jet around points straight to mechanical issues. A little spooge is not all right, epa hazard! What does the plug look like?

Just put a new plug in right before the last ride. Took it out for about 2hrs with pretty much all different throttle/rpm levels. A good amount of low rpm riding and several runs at a full throttle sustained 2nd gear hill climb. Plug was clean and not black at all. Also, I lose no oil from the tranny. But, I do as I stated get spooge that drips off the silencer.

Can anyone tell me where the Power jet is on the PWK?

The previous owner did have the needle at the top setting of the needle(leanest setting) when I bought it, but I did not like it running that high of a clip position. I drop the clip down one notch and it also seemed to gain some mid-range back, so I think I made the correct decision for that circuit. Also had a 158 main when I got it, but again I took it up to a 162 and it seemed to pull harder on top so I think I made a good decision there too. Just so that we can have all the cards on the table, I also am running a BR8EG plug(came in the bike, but is not stock Br9EV was I believe)

From what I could tell the previous owner just leaned out all the circuits but the pilot in an attempt to keep it from fouling in the trails. They trail rode it as well and were admittedly not skilled riders.

 

[AV8R]

looks like on this picture that it is on the intake boot side just inside the throat. #16159

http://www.mrcycles.com/fiche_section_detail.asp

A little different than my YZ250. So I could be wrong about how it functions if Kawai did it different than Yamaha. See if your manual says anything about it. If you don't have one I would reccomend getting one.

On second thought that really does not make sense to me to have it inside the throat of the carb. the only thing it could do there is meter air. It must be on the carb body where the float bowl meets. Hard to tell from the cruddy picture.
Mine is located on the float bowl where it meets the carb body. Check in that area it is a very small jet.

 

[whenfoxforks-ruled]

Yes, that is it.50 is stock, try a larger number and see if it leans it out off idle.

 

[Redrodent]

Just a suggestion. It is possible the nozzle (where the needle slides through) is worn. I don't think its replaceable on the PWK. If this is the case, it throws the stock jetting out the window at low rpm. You may want to experiment with a needle with a larger straight section or two. Mine is terrible and took a lot of T&E to get the needle/pilot combo running crisp and spoogless.

Just be sure to take lots of notes :nod:

 

[2strokerfun]

In my experience, the needle usually wears out before the needle jet. And yes, it makes the bike a smoking spooge machine at low rpms. But with a 2000 model, I kind of figured needle and jet weren't too badly worn. And he really didn't talk about it running too poorly. But for the $7 to buy a new one, it's worth a shot.

 

[whenfoxforks-ruled]

Replace the float valve while you are at it, once a year.

 

[flynbryan]

In my experience, the needle usually wears out before the needle jet. And yes, it makes the bike a smoking spooge machine at low rpms. But with a 2000 model, I kind of figured needle and jet weren't too badly worn. And he really didn't talk about it running too poorly. But for the $7 to buy a new one, it's worth a shot.

Nah. Needle and nozzle are fine. Bike has really not seen very much use. I'd be very surprised if it has over 50-60hrs on it and though it appears to have been laid down a few times it was not abused.

I'm going home this afternoon and throwing in the #40 pilot. We'll give her a try this weekend and if it runs like a dog I'll throw the #45 back in it till I get a #42 to try.

Also wanted to say I appreciate all of ya'lls help with this. Its been greatly appreciated. ;)

 

[flynbryan]

Little update for those interested...... Got the chance yesterday to swap out the #45 for the #40 again yesterday. Temps were 60 degrees and substantially warmer than the first time I tried the swap(about 45 degrees). I believe the temp change is what really made all the difference. Yesterday I was able to swap out the jet and this time could get the performance best at 1_1/2 turn out on the airscrew. ;) Didn't get to do much other than tear up some grass in the yard, so really didn't have the chance to see how it worked on the trail. I am going riding here in about a half hour, so we'll see how good it works today. I know just from riding around the yard that the throttle response is MUCH improved, so I think its going to be a great day!