Jetting woes...

[wanaride]

New '03 KDX200 with stock jetting smoked badly, suspected jetting was too rich:
- 32:1 Bel-Ray H1R
- choke lever NOT on
- air screw 1 turn out
- I have read carb jetting tips on JustKDX and Eric Gorr's site.

Replaced #48 pilot with #45 pilot and noticed some improvement, less smoke overall but still smoked quite a bit when I rolled on the throttle. Peppier response too. Air screw adjustment didn't seem to help.

Removed airbox snorkle, drilled several 1/4" holes in lid and test rode bike with #45 pilot (stock main jet and jet needle position). Smoked MUCH worse, smoke more grey than blue, engine made a throaty bass rev noise (didn't do that before the airbox mod). VERY sluggish response, definitely NOT an improvement.

Tried #42 pilot and noticed no improvement.

Went back to stock #48 pilot, still sluggish and smoked a lot, worse than before the airbox mod.

Finally, I went to a #45 pilot and a #158 main jet (jet needle still in stock position). This seems to be an improvement but definitely not "there"; lots of smoke when I roll on the throttle. Power is OK, better than before but not as good as I expected. Still got that throaty deep engine sound, though not quite as bad as before. My guess is it is still too rich, especially towards WOT.

Should I go to a #155 main jet? Lower the needle one position? I'm afraid of seizing the engine; what are the signs the jetting is so lean that seizing is a possibility?

The upside of all of this is I can disassemble a carb in no time...

 

[skipro3]

The KDX will give you plenty of notice that it is going to seize. There will be pinging noises coming from the top end, and it won't be blowing 2 stroke smoke as much as you discribe. Use a fresh plug and check it for white, blistered appearance as well. Be sure your float level is correct and that the float needle is working properly. Be sure you didn't get a bad batch of gas by starting over with the fuel/oil. Check the needle position. It sounded like you haven't checked it yet. These can be a little tricky getting seated back in correctly and if not done right, it will cause a very rich running condition. Be sure to use a shop manual or Canadian Dave's site for this. Dave has a couple of tricks for getting this done right.

 

[canyncarvr]

What he said.......

The jet to select first is the main. If you don't, you're wasting your time. The main jet can easily be off enough to effect all the lower circuits..clear down to the slow speed (pilot) circuit.

You select that jet using the WOT plug chop method with subsequent plug inspection. No-one can tell you what to use, as bikes vary, conditions vary and bike riders vary hugely!

That said a 155 won't often be 'too small'. It all depends...on temperature, humidity, riding style, fuel, premix oil and of course, the phase of the moon.


It is FM after all..........;)

BTW, '..drilled several 1/4" holes in lid ..' isn't going to have much effect at all. But, the following reference to '...throaty bass rev noise ..' kinda makes me wonder.

With the airbox lid 'properly' modified, you'll hear a dead duck quack noise (honk honk) when you wick-it quick at lower speeds.

..but 'several' 1/4" holes won't do that.

re: seizures and the kdx

Not a common tendency unless you run some kind of junk oil like H1R.


Oh........:( You do.

There are tons of opinions about which oil is the best, and everyone's is better any anyone elses. Except I have personal experience with seizing my kdx with H1R. It is crap most excellent! You couldn't pay me enough $$ to use it.

But you're welcome to it! (imo and all)

Cheers!

 

[Houndog]

Geeez, now you make me feel bad for using Belray! :think:

How about regular 10w30, maybe just put some in the base evrytime I change the piston? Or would that be the same as using H1R? :laugh:

 

[canyncarvr]

I used quacker state 30W in my R5. 47,000 miles on the first topend.

Don't get me wrong...if you like H1R, you are certainly welcome to have your own (misguided as it may be ;) ) point of view. The junk screwed my bike and I figure I'm welcome to advertise it.

 

[Chief]

I agree w/ canyon on the 'main first'. Also, I don't know anyone that uses the needle in the mid position. All are one lean. At 1000ft in summer temps usually hit 80-90 and I set mine one from the leanest. In the winter when temps are 30ish I can set it in the middle. The setting on the needle one step in either direction makes a drastic difference for me. If the main is too rich the bike will bog wide open and die on long steep hills. You will eventually get it right if you keep on it and follow a standard set of instructions for jetting.

Chief

 

[Roland C]

wanaride,
It sounds like you've made some good progress on your jetting. Several people have had some luck in reducing the amount of smoking by going with a 40:1 gas/oil ratio instead of 32:1. I'm not exactly sure I can explain why since this makes the gas/air mix in the carb a little richer (thinner gas mixture goes through the jet easier). Maybe less oil to burn means the gas mix burns cleaner, hence less smoke out the pipe? You obviously don't want to take this too far or you'll lose the lubrication value of the oil. Again, I'm not terribly knowledgeable on the subject, but it would make sense. I'm running H1R right now at 40:1 and it seems to do okay. However, with CC's shining review of H1R (in several threads) I'll try another brand when I run out of what I've got. On the other hand, my dad has run Belray MC1 @ 50:1 in his 1985 Yamaha IT200 since he bought it new and hasn't ever had a problem. It still runs like a champ.

Also, don't worry too much about color on the tip of the plug after a WOT plug chop. Worry more about texture (shouldn't be blistering, as someone said) and look for the mixture ring at the base of the ceramic (hidden by the threads). The dark ring should be somewhere in the 2mm thickness range. (good plug reading thread: http://www.dirtrider.net/forums3/showthread.php?s=&threadid=60392&perpage=20&display=&pagenumber=1) My bike tends to run a little hot and the tip is pretty white even running a 160 main. You should be safe with a 155. Also, needle position made a big difference on my KDX. One notch leaner from stock runs pretty good. Hope that helps. Let us know what you come up with.

 

[JasonWho]

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[wanaride]

Thanks guys...

Yeah CC, I didn't think the holes would do much either, but I saw a picture on this forum of a lid with similarly drilled holes, so I went for it and removed the snorkel too.

From what I read I thought removing the snorkel alone would be a good thing; that is why I went back to stock jetting with the airbox mod. The results were most disappointing.

And I almost forgot; with 158 main, 45 pilot, airbox mod, AS=1.5 turns out, the bike still starts on the first kick.

I suppose my plan now is to (1) go down to a 155 main, and depending on that, (2) lower the needle one position to lean it even more. And maybe I'll try Motul or Mobil MX2T on my next fillup...

Man, this is an outstanding resource, as good or better than my service manual!

 

[skipro3]

Holycrap CC, I slammed H1R a while back and got hollered at by JasonWho. "skipro3, entire world, others: If Bel-Ray was crap, why would some of Team Kawasaki use it!?!?!?!"
I ended up apologizing and saying I was wrong even though I knew you had troubles with it. Rich doesn't like it either after seeing what it has done to lots of engines. After my chain episode with Jaybird, I desided that if anyone ever disagreed with me again, I would just end the fight by saying they are right and backing slowly towards the door. Mobil MX2T is my preference. (But who cares!)

 

[canyncarvr]

Aw...c'mon! There's more piss'n-vinegar in you than that!;)

I don't care who agrees, who doesn't. It don't matter a whit. Also, who has used it for how many decades doesn't matter either.

The fact is my bike stuck tight on the first tank with that junk. Peeled the plating right off the cylinder wall. Yeah...it was a worst case situation, a roll off of throttle from WOT/70+mph. Still, the oil failed.

I'll never change my mind just because someone disagrees with me. They can present facts and prove me wrong....I'll be the first to kiss the dirt.

But because they disagree? Ha! It is but to laugh!!

BTW...welcome 'back'!

re: 'similarly drilled holes...'

My point was the exactness and specificity of '..drilled several..' I don't think there has ever been a pic posted of an airbox lid with three 1/4" holes drilled in it.

In any case.....with the modified lid, the bike will run somewhat more lean than with an unmodified lid (all other things being unchanged). With more air..and with the carb properly set up, your bike will run better than it ever has! Guaranteed.

You've got a lot to look forward to!!

BTW summore, 40:1 is indeed richer air/fuel-wise than 32:1. There's more gas per given volume fluid. 40:1 is considered 'safe' by most if not all on a 200 woods bike like the kdx 200/220. Consider that there is documented proof that the more oil (the lower the ratio number) that is mixed with the fuel, the more power a 2-stroke makes......all the way up to plug failure due to too much oil.

Cheers!

 

[JasonWho]

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[skipro3]

O.K. O.K. JasonWho....you didn't holler. My mistake. I was wrong. :worship:
(feeling for the door knob while backing up) :eek:

Man, you have guts! Am I reading correctly between the lines here and you might possibly be insinuating that CC might not be able to discern the difference between 40:1 and 400:1?

BTW My new theme song
http://www.musicsonglyrics.com/M/Matchbox 20/Matchbox 20 - Unwell lyrics.htm

 

[Houndog]

Just because canyncarvr can't mix a certain brand of oil properly is no reason for the rest of us not to use it :)

 

[skipro3]

CC, Jason, et al, you do understand I'm only joking,.....right?

 

[mudwalker]

I finally used up the rest of my Bel-Ray H1R oiling the chain on my sons TTR90. Oh it also worked well to free up the rusty kickstand hinge, I like the stuff.

 

[JasonWho]

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[wanaride]

This site is OUTSTANDING!

I had my carb in pieces last night and I wasn't sure how to disassemble the slide to get to the needle. I left the bike, logged on and did a search...10 minutes later I had the needle out...I love this site! This is better than my service manual! (BTW, the service manual said NOTHING about the slot on the white nylon cap needing to be lined up; it just says "Disassemble the slide." I might have missed that if it weren't for CC pointing it out.) Like I said, I love this site!

WOW, now I understand what the hemocrit is for! What a pain...I've got to get me one of those!

I bumped the clip up one position, left the main at 158 and the pilot at 45, but it was too late to try it out. We'll see how she does...

 

[canyncarvr]

Next time you have the needle retainer nut out consider putting some neverseize on the threads. It tends to 'stick' after awhile...and the nut being hollow you can crush it fairly easily.

Might ruin your evening if your plan is go riding the next day!

A hemostat is nice for holding the stuff together. If you drop the spring/retainer etc on the floor, make sure it's spotless when you put it back in. Spray it down with brakleen. A bit of junk can cause serious problems it it's stuck in the wrong place. WOT when you least expect it!

I'd advise clamping the throttle cable behind the serrations on the jaws. On the flat. The less stress on the cable the better.

Still, holding the nylon retainer between thumb and forefinger, then compressing the spring by holding the cable end and sliding your fingers up the cable gives you a pretty good bit of cable hanging out to clip into the needle nut.

One more thing. When you wrench on the needle nut on removal, make SURE you don't put any pressure on the needle. When you're trying to hold the slide steady, it's easy to tweak the needle.

Good deal! Let 'er rip!! ;)

***edit**
re: 'Just because canyncarvr can't mix a certain brand of oil properly is no reason for the rest of us not to use it.'

Now that's funny!

 

[bigred455]

Originally posted by canyncarvr
What he said.......

The jet to select first is the main. If you don't, you're wasting your time. The main jet can easily be off enough to effect all the lower circuits..clear down to the slow speed (pilot) circuit.

You select that jet using the WOT plug chop method with subsequent plug inspection. No-one can tell you what to use, as bikes vary, conditions vary and bike riders vary hugely!

That said a 155 won't often be 'too small'. It all depends...on temperature, humidity, riding style, fuel, premix oil and of course, the phase of the moon.


It is FM after all..........;)

BTW, '..drilled several 1/4" holes in lid ..' isn't going to have much effect at all. But, the following reference to '...throaty bass rev noise ..' kinda makes me wonder.

With the airbox lid 'properly' modified, you'll hear a dead duck quack noise (honk honk) when you wick-it quick at lower speeds.

..but 'several' 1/4" holes won't do that.

re: seizures and the kdx

Not a common tendency unless you run some kind of junk oil like H1R.


Oh........:( You do.

There are tons of opinions about which oil is the best, and everyone's is better any anyone elses. Except I have personal experience with seizing my kdx with H1R. It is crap most excellent! You couldn't pay me enough $$ to use it.

But you're welcome to it! (imo and all)

Cheers!

.........

What you mentioned about changing the main first is proven by my experiences. I switched over to av fuel 6 weeks ago and I was definetly running rich very noticeable up top .I went from a 165 stock to a 160 main. I was telling my friend how amazed I was not only did the top wake up,but the bottom and mid became much stronger. I tried to dial in the bottom and mid more to see what I can get. Put it this way the main did it all.... Good post!!!!!!!!! :thumb:

 

[Chief]

BigRed,

That's Good News to me since last week I went to go leaner on the main and found that the 158 I just took out was the smallest I had. Went to the dealer and BeeGeezus thay had it in stock. (Heart Attack)

I plan on putting the 155 in before I ride again and I'm getting pumped a bit since the 158 just barely cut it for me. With a 160 in summer it was dogging. Hopefully this change will wake up my bike even more and put it spot on.

Chief

 

[wanaride]

Well, I'm not sure if I'm spot on, but here is where I'm at:
Pilot = 42 (stock 48)
Main = 155 (stock 160)
Needle = 2nd clip from the top (stock 3rd clip)
AS = 2 turns out.
Airbox = snorkel removed, 13 x 1/4" holes drilled in it too!

I went riding at Brushy Mtn Sat and the power seemed good, not nearly as much smoke either. She does smoke when I lug around the yard and then punch it...maybe that is to be expected?

Even if I'm not spot on, I'm close enough to stop worrying about it. Thanks for all of the help!

 

[Chief]

Glad you got what you needed here wanaride. Most of us know what it feels like to have a new bike perform underpar. My bike will smoke and even take a few good revs to clear out nice and high after I lug thru tight trails. I think it's the spooge in the pipe burning off. BTW a bud of mine put a new pipe on his, not sure but I think it's the FMF REV. It really woke his bike up a lot. I can tell he likes it more and the bike does have more snot. He was told to keep the original silencer. He saved a few bucks there and is very happy with it. He has the KDX 200 BTW. Anyway, happy trails and remember you can always make it faster when you want to.

Chief

 

[JasonWho]

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