Need Help! Tuning issue 98 KDX200

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zepplin153
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Re: Need Help! Tuning issue 98 KDX200

Post by zepplin153 »

yes but i have to lean it about 15-20 degrees before i get leakage. Where should my clip be on the needle? Now its on the middle.
'98 KDX 200 (KLX300 Forks)
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Re: Need Help! Tuning issue 98 KDX200

Post by Julien D »

That sounds about right on the overflow leakage. Just making sure it wasn't clogged. The middle is stock, if you raise the clip up it will drop the needle further into the needle jet, leaning it out a bit. Go ahead and move the clip up a notch or two and see what that does.
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Need Help! Tuning issue 98 KDX200

Post by zepplin153 »

scheckaet wrote:160 is big.
Read on the jetting guide in the jet and needle section.
the main has the most effect at wot.
if the kips actuates when you rev the engine then your kips is ok (whether you stand still or ride), the timing could be off.
FYI the manual has the left and right sub-valve wrong, they show the right on the left and vice versa.
they were in backwards! exactly backwards. perfectly aligned..... Backwards... whats funny about it... in the manual there is a big warning box that tells you the wrong thing to do. there is some Japanese dude out there playing some evil joke on us. "aaaww silly yankee dogs... i show dem... we make dem repair backwards.. ROR"
'98 KDX 200 (KLX300 Forks)
zepplin153
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Re: Need Help! Tuning issue 98 KDX200

Post by zepplin153 »

Julien D wrote:That sounds about right on the overflow leakage. Just making sure it wasn't clogged. The middle is stock, if you raise the clip up it will drop the needle further into the needle jet, leaning it out a bit. Go ahead and move the clip up a notch or two and see what that does.
I already tried it on the 2nd from the top..... same thing. would i really need to go all the way to the top?
'98 KDX 200 (KLX300 Forks)
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Re: Need Help! Tuning issue 98 KDX200

Post by zepplin153 »

OK so i am stuck. My new jets are not in yet..... But to all you guys who say my jets are too rich I should still get it to crack open good. Its still not opening up right in the top end RPMs and it runs a little rough all throughout.
- I have the needle clip in the top groove
- I have gotten it to run perfectly when i turn the gas partially off (and off just before it runs out of gas). What does this mean?
- It runs a lot better when the air screw is almost all the way out. I understand this is an indication of pilot jet too rich. but still I cant get it to run out with good power in the top end unless its almost out of gas.
- I also lowered the float height a tiny bit. 1mm
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Re: Need Help! Tuning issue 98 KDX200

Post by Julien D »

Lowering float height is not a good idea. Think logically about this a second. What happens when the bowl is running out of fuel? Mixture leans out. Lowering the float level is not going to help, and may very well cause you problems down the road. It will not lean out your A/F ratio, but may cause the bowl to run out of fuel in certain situations, which is never good. There is simply no way to compensate for overly rich jetting. Your theory that you should be able to get it to run out right as it is is just not correct. Sorry. My advice? Wait till you get the jets and go from there. It's obviously running rich, the only answer to that is jetting.
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Need Help! Tuning issue 98 KDX200

Post by rbates9 »

What kind of hit are you expecting from the KIPS? if you are looking for a MX type hit from the bike you won't find it. KDX's are a much more mellow feel. How much did you ride the bike before the rebuild? Are your expectations realistic for this bike?

Don't get me wrong, when these bikes are running right the do come alive and go but in a different way.

I have found at times with a problem that is kicking your ass for too long it is best to forget everything you have done and start over from scratch. Sometimes you tend to over look something simple and look to hard for something else.

First thing to do with any bike that you have any questions about the performance on is to make sure everything it up to snuff.

1. Check the compression and compare to spec. (I know you just did a bunch of work to the top end and it should be good but still check it. I checked the 12 year old top end on my bike just before removing the engine and had a reading of 150 Psi, I put in a new piston and rings then checked it again after about 5 hours of riding and the "new" top end had 145 Psi so with out a gauge you can't assume all is well.)

2. Replace the spark plug with a new plug, not a good used one or one that you cleaned, A new one.

3. Make sure the silencer is clean. You can blow air thru it if you can't disassemble it and compare what goes in to what comes out.

4. Check that the timing and ignition is good, remove the flywheel and verify the lines are lined up at least. Check the coil for the proper resistance. Don't be afraid to check it more than just when it is cold, run the bike and see if the resistance goes out of range as well

5. Make sure that the fuel system is clean. When the carb comes off take all the jets out and clean all the passages.

6. Start with a good clean and not overly oiled air filter.

7. Do the jetting steps. Take your time and make sure the rest has been done or the time spent jetting will be for nothing. and if you don't have the right size jets to move to the next step then wait till you do, randomly tossing in jets will probably put you farther behind than ahead.

I know you are probably thinking that it is a waste of time to redo everything but it could be a bigger waste of time if you don't.

Good luck and be patience...
31
zepplin153
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Re: Need Help! Tuning issue 98 KDX200

Post by zepplin153 »

Got you loud and clear. In fact I just adjusted the float within specs. It measures 18mm which is within the 16mm +/- 2mm the manual recommends. Let me tell you what I found: http://www.thumpertalk.com/topic/844185 ... msearch__1

This guy was talking about a O-ring for the jet block. I did a chem dip when I first cleaned the carb. And I left it in for about 2 hrs. Chem dip would get those o rings fast.

A few min ago I turned the carb upside down and filled with a little gas, used my finger to plug the jet ports, and blew gently some air through the bottom of the pilot jet. There were bubbles like crazy around where the jet block seats on the carb body. This could be my problem! It could be running rich if it is sucking too much gas in around that jet block. What do you think?

The jet block has these tamper proof screws. how should I handle this? New carb? replace the o-ring?
'98 KDX 200 (KLX300 Forks)
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Need Help! Tuning issue 98 KDX200

Post by zepplin153 »

rbates9 wrote:What kind of hit are you expecting from the KIPS? if you are looking for a MX type hit from the bike you won't find it. KDX's are a much more mellow feel. How much did you ride the bike before the rebuild? Are your expectations realistic for this bike?

Don't get me wrong, when these bikes are running right the do come alive and go but in a different way.

I have found at times with a problem that is kicking your ass for too long it is best to forget everything you have done and start over from scratch. Sometimes you tend to over look something simple and look to hard for something else.

First thing to do with any bike that you have any questions about the performance on is to make sure everything it up to snuff.

1. Check the compression and compare to spec. (I know you just did a bunch of work to the top end and it should be good but still check it. I checked the 12 year old top end on my bike just before removing the engine and had a reading of 150 Psi, I put in a new piston and rings then checked it again after about 5 hours of riding and the "new" top end had 145 Psi so with out a gauge you can't assume all is well.)

2. Replace the spark plug with a new plug, not a good used one or one that you cleaned, A new one.

3. Make sure the silencer is clean. You can blow air thru it if you can't disassemble it and compare what goes in to what comes out.

4. Check that the timing and ignition is good, remove the flywheel and verify the lines are lined up at least. Check the coil for the proper resistance. Don't be afraid to check it more than just when it is cold, run the bike and see if the resistance goes out of range as well

5. Make sure that the fuel system is clean. When the carb comes off take all the jets out and clean all the passages.

6. Start with a good clean and not overly oiled air filter.

7. Do the jetting steps. Take your time and make sure the rest has been done or the time spent jetting will be for nothing. and if you don't have the right size jets to move to the next step then wait till you do, randomly tossing in jets will probably put you farther behind than ahead.

I know you are probably thinking that it is a waste of time to redo everything but it could be a bigger waste of time if you don't.

Good luck and be patience...
31
Kick: its not getting in there like it should. It has about another 20-30% to offer up top. I know it.
time on the bike: I rode it for about a month before rebuild.
compression: is great
Plugs: i bought a bunch the other day and have used 3 already. not because they are fouling but because I want to be safe.
Silencer: clean
Timing: aligned perfect
Ignition: this is questionable. the ground is not in contact with metal. I am going to scrape powder coat back to metal today just to be safe
carb Clean: I think this is my problem... I think I cleaned it too good. I did a chem dip for a couple hours. And I just now discovered the jet block and its lovely rubber o ring.
Air filter: Goldilocks zone. not too oily.. juuuuuust right.
Jetting steps: this would be off if the jet bock o ring is not sealed well, which is the case as I confirmed with a little gas and some air pressure. Or am I wrong here?

It is absolutely running rich one way or another. I have ordered 45/155, but something tells me with the jet block not sealed well it wont make a difference what i have in there.

Now I am wondering if I should buy a new carb or try to replace the o ring. as I will have to jerry rig some kind of tool to take those tamper proof screws out of jet block.

:hmm:
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Need Help! Tuning issue 98 KDX200

Post by rbates9 »

I can't remember if those screws are normal torques with the pin in the middle or if they are the five point screws with the pin in the middle. :hmm: If they are normal torques then most auto tool supplier should be able to provide them for you. They are not that hard to come by, Most of the bit sets I have come with them. If it is the five sided screws then find a MAC tool truck and they should have a set and might sell you just the one you need. Mac is about 1/4 the price of Snap On for the same set.

Finding the seal could be the challenging part. Try calling Ron Black. He tends to replace them when he does any carb work.

A leaking jet block could be your problem but it seems that it might want to run lean but with an incorrect float or a float needle that isn't seating great then it might do something different.

Good find none the less! :grin:
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Re: Need Help! Tuning issue 98 KDX200

Post by zepplin153 »

i thought the same thing about a seal making it run lean but it is also possible that the opposite would happen. That seal is leaking really close to where fluid level should be inside the float bowl. So it could be sucking extra fuel. I found the o ring from MXsouth.com but I will try ron black too. i will buy it from whoever I can get it from before friday. because on saturday its off to durahm town GA! and i will go even if i have to coaster ride it!

Float seems perfect i measured its 18mm which is within the 16mm +/- 2mm.

Float needle looks perfect. its not worn and there is no buildup on it. the brass seat looks clean too.

Those jet block bolts are 6 points with the little pin in the middle.
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Re: Need Help! Tuning issue 98 KDX200

Post by rbates9 »

zepplin153 wrote:
Those jet block bolts are 6 points with the little pin in the middle.
Then you should have no problem finding the correct bit. RB will only deal in money orders so it would take probably a week and a half to go thru him. You would have to mail him a MO and wait for him to get it then he would mail you back the parts.
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Re: Need Help! Tuning issue 98 KDX200

Post by Julien D »

Oh. New information! Dipping or soaking a PWK is a no-no. I've replaced two jet block gaskets due to this. As for the security type torx bits, you can snap out the little pin in the middle with a small flat driver, and remove them with a normal torx driver.
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Need Help! Tuning issue 98 KDX200

Post by zepplin153 »

I am dialed in now.

Thanks for all the help. It was my first restoration and I really could not have done it without everyone's help. I will be donating for sure to show my appreciation.

To recap:
- I changed my jet block o ring. Didnt make a huge difference to my problem
- changed jets from 48/160 to 45/155 and it was almost there. top end was still a little rough better but rough.
- moved the clip to the second from the top groove (leaning it out a tiny) and BAAAAAAAM... it was money. :supz:
'98 KDX 200 (KLX300 Forks)
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Re: Need Help! Tuning issue 98 KDX200

Post by JBM KDX »

Been reading through the threads finally to come across my current running problem I'm having...which is the same as in this thread..bottom end but rough low power mid to nil top end
after buying a pretty rough but cheap (wish I had more money to spend!!) 95 KDX200
I decided to strip back much of it and give it some love ....the bike was running very rich muffler full of oil etc KIPS also pretty bad stripped it down cleaned refitted KIPS triple checked it sure I did it right....piston bore not perfect but seemed to have some power on top when test rode the bike ...will do compression test soon

I have changed jets from 48/160 to 40/155 lifted the needle clip to the three from the top or middle

repacked the muffler fixed a hole in the pipe...fitted new 9 spark plug was running 8 NGK

running Motul 800 40:1

also fitted new guards , bearings, gaskets,fork seals,chain spockets, fixed many rough work from prior useless owner

after many many days work and $$$ I'm really hoping to have a good running bike for the holidays

If anyone has also had the same issues be great to here how you fixed them...first two stroke I've had for awhile ...got no decent bike mechs locally that aren't complete rip-offs
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Need Help! Tuning issue 98 KDX200

Post by JBM KDX »

Think I may have fixed the issues with a 150 main jet and clip right at the top bike ran much better after a 10min run the plug come out brown /white insulator/black further away from spark centre

also took off the air-box cover and changed back to the old 8 ngk sparkplug

did a compression test only 90psi ...did buy a new piston but bore needed repaired going to cost way to much $700-$800nzd for the age and the fact I only brought the bike to save up cash to buy a late model 2st I think I just ride it with the lower power ....

checked the stator nice and dry so crank seals are fine
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Re: Need Help! Tuning issue 98 KDX200

Post by zepplin153 »

jbm,
did you read my edits from my original post? look at the very first post i went back and put down all the things i ended up learning. also, if youre having the same trouble you may be too rich in the main still. Also, if your reeds arent seating properly you will loose power (may sound gurgle like). follow this link to the best jetting guide i have ever read.... EVER! http://www.duncanracing.com/TechCenter/ ... etting.pdf
Finally, If your compression is 90 its way low. I dont advise leaving it alone. im going by memory but i think 120-150 is normal range. yours is certainly low which you have determined already. Your cylinder needs to be replated. dont hone and dont sleeve! get it bored then plated its the only way to go. and DONT PAY $800nzd! holly crap thats high ($660usd). I got mine done for about half that. It may be worth shipping to a US shop to have it done. It may still be cheaper. Im thinking you could get it done for about $450nzd even with shipping. I have a couple buds in FL that do it right at good prices. Side note, you will need to rejet after plating and new piston/rings. Let me know if you have any other questions.

Hey once you get this bike running you will be hard pressed to find another bike to perform better in the woods. given my choice i would go with a ktm but my 2nd choice (and a close second) would be the KDX. when it comes to pure performance and affordability they are a no brainer. Certainly not a track bike but I eat KTM riders up on the trail.
'98 KDX 200 (KLX300 Forks)
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