96KDX Jetting help, Running rich

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96KDX Jetting help, Running rich

Postby KDXRipStick » 09:54 am Apr 02 2018

Hey guys I need some advice/help on getting my KDX that I just bought running right.

When I first got it home it was flooding/fouling plugs fairly badly and really wouldn't open up/start running good until 4th gear.

The jets in it were 152/42 with the needle cup 2nd from the top.

I accidentally went up instead of down in jet size and went with a 155/45 jet combo and moved the needle from 2nd to the 3rd clip.

The bike now pulls hard in 3rd and up but still bogs 1st and 2nd hard especially at lower rpm.

Now the weird thing is when I took the bike up the street in the woods it actually performed better. A straightaway I normally was shifting to 3rd in I now was winding 2nd out fully and not having to shift to 3rd cause I was hauling so much ass.

The bike is splooging and smoking so I know I made it even more rich.

Can anyone point me in the right direction?

Should I jump down to 152 main and a 40 pilot or all the way to a 150 main with 40 pilot? Stay on 3rd needle setting?


Thanks

The plug on the right is after I went out and ripped on it with the new jets.

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Re: 96KDX Jetting help, Running rich

Postby John_S » 10:30 am Apr 02 2018

Jetting isn't gear specific. Main thing though is that you don't change two jets (or a jet and needle setting) at the same time. Concentrate on the pilot until its good, then the needle until its good, then the main jet. Have you read the jetting guide? Its worth the time to follow it even though it takes a while to get you carb set just right.
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Re: 96KDX Jetting help, Running rich

Postby KDXRipStick » 10:35 am Apr 02 2018

Yes I did read the jetting guide.

I guess I will start at Square 1 and adjust the pilot jet until I get it right and then go front there.

Can you change the pilot or without removing the carb? Or just the main through the carb drain plug?




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Re: 96KDX Jetting help, Running rich

Postby KDXohio » 10:41 am Apr 02 2018

Rotate the carb and pop the bowl off to replace the pilot, the main can be done through the drain. Start with one circuit at a time, you can be rich in the pilot lean in the needle and rich in the main or any combination of things so changing everything at once leads to chasing your tail!
1990 KDX200 FMF Fatty, Answer VFC silencer, Boysen rad valve, Wiseco Piston, KX125-J series KYB USD fork conversion, J series front brake assembly, air-box snorkel removed, Acerbis Headlight, KX450F Front fender, Pro Taper RM bend bars, ASV front Brake lever, MSR Clutch perch and lever, RB Head mod, 36mm PWK carb, Trail Tech Kickstand.
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Re: 96KDX Jetting help, Running rich

Postby John_S » 10:47 am Apr 02 2018

No unfortunately just the main.

Make sure square 1 is the float. I have a hell of a time tuning my bike with the float height set at anything other than 18mm.
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Re: 96KDX Jetting help, Running rich

Postby John_S » 10:49 am Apr 02 2018

I've rotated it before and changed the pilot like ohio suggested. If the carb top cap and slide are out you can rotate it pretty far.
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Re: 96KDX Jetting help, Running rich

Postby Jim B » 11:52 am Apr 02 2018

Make sure the reeds are in good shape.
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Re: 96KDX Jetting help, Running rich

Postby KDXRipStick » 12:06 pm Apr 02 2018

Sorry guys forgot to add that I do have fresh air filter installed, snorkel removed, fresh plug installed.

I have receipts for the silencer from the PO and it was bought in 2017 but I do believe it needs repacked so I bought a repack kit.

I believe my bike has Upgraded Reeds but I will need to take it apart and check them and condition.

When I get home from work later I'm going to check the pilot circuit and start dropping it down until it's operating as it should.

My bike currently won't even idle.

Sorry for all the newb questions, this is my first bike.






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Re: 96KDX Jetting help, Running rich

Postby ohgood » 12:56 pm Apr 02 2018

the mixture screw matters too don't neglect it!
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Re: 96KDX Jetting help, Running rich

Postby KDXRipStick » 01:05 pm Apr 02 2018

I'm going to mess with my pilot circuit and the mixture screw to determine if I have the correct pilot jet in there now and swap it unit I get it correct.




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Re: 96KDX Jetting help, Running rich

Postby John_S » 01:42 pm Apr 02 2018

Let us know how it goes. I would check the float height, reeds, and repack the silencer before replacing any more jets so you're not chasing your tail like I have plenty of times. It doesn't hurt to try the air screw tuning now though since its quick and you don't have to tear into it. Having the engine at full operating temperature (and a quick rip to make sure its cleared out) is key when you start turning the air screw. When you turn it in all the way make sure you only go until its lightly seated, not cranked in. My highest idle and ideal throttle response are about a whole turn apart from each other. Around 2.5 highest and around 1.5 final setting.
Last edited by John_S on 01:52 pm Apr 02 2018, edited 1 time in total.
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Re: 96KDX Jetting help, Running rich

Postby KDXRipStick » 01:51 pm Apr 02 2018

Thanks for the Advice John.

I forgot to mention I'm at 80' above sea level and very close to the ocean so it always humid.

I'm still trying to understand what I did yesterday that made it pull harder at WOT. I'm thinking it was maybe the needle adjustment.

All report back once I get home from work and start messing with it.




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Re: 96KDX Jetting help, Running rich

Postby KDXRipStick » 04:27 pm Apr 02 2018

Ok guys update since I got home and started messing with the bike.

Cranked it, took it for a spin to let it warm up. Ripped it twice to clear it out.

Got back to the house and will I was blipping the throttle I unscrewed the idle screw all the way trying to get the bike to idle and it wouldn't.

With the idle screw maxed out I started toying with the air screw. I wasn't able to get the bike to idle but I WAS able to get some of my throttle response back in the low end.

I took it around the yard and gave it a little throttle where it would normally bog and the bike stood up on me.

Am I that far off with the pilot jet currently causing it not to idle?

At WOT this thing rips hard.

Thinking I should drop a jet size on the Pilot and go from there. Sound good?

Check out this splooge just from riding for 10 mins.
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Re: 96KDX Jetting help, Running rich

Postby John_S » 08:40 pm Apr 02 2018

On your post you said you UNscrewed the idle screw all the way trying to get it to idle. Turning the screw in raises the idle. If the front end stood up where it bogged before then you're going in the right direction. Do you know how far out the air screw was turned with the best throttle response? If you had it 3 or more turns out then you need to go smaller pilot.

In my own experience the only time my silencer has looked like that has been from a rich needle setting. When my main is too rich it's my back fender that gets splattered black. Next time you take it out try the full throttle rip to clear it out, wipe the silencer clean, and then run around for 5 minutes or so never going beyond 1/2 throttle and see if the silencer is still getting that much oil running down it. That whole last paragraph could very well be bad advice, but it's what I would try. For me it's trial and error, heavy on the error.
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Re: 96KDX Jetting help, Running rich

Postby Jason » 10:28 pm Apr 02 2018

If you got a magic note from a genie telling you perfect jetting, then you changed to perfect jetting, guess what. All the old excess oil is still in the pipe and spark arrestor. :doh:
Thank you, Julien D for all your hard work!

PLEASE! Do not "dip" PWK Keihin carbs in Berryman's to clean them! It will damage the internal o-ring (jet block gasket).
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Re: 96KDX Jetting help, Running rich

Postby KDXRipStick » 03:33 pm Apr 03 2018

Of course I had a magic genie give me the correct Jetting!

I swapped from 45PJ to 42PJ and couldn't get it to idle.

Swapped a 40PJ in and with the idle screw all the way in (Max idle) and the air screw 3 turns out.

It now idles but is extremely close to shutting off.

Throttle response is exceptionally improved but I'm still way rich somewhere.

Should I stay on the PJ and keep dropping it until I can get a higher idle? Or move to the needle or main jet?

I know that lean or rich the pipes still going to splooge until I repack it.






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Re: 96KDX Jetting help, Running rich

Postby ohgood » 05:58 pm Apr 03 2018

KDXRipStick wrote:Of course I had a magic genie give me the correct Jetting!

I swapped from 45PJ to 42PJ and couldn't get it to idle.

Swapped a 40PJ in and with the idle screw all the way in (Max idle) and the air screw 3 turns out.

It now idles but is extremely close to shutting off.

Throttle response is exceptionally improved but I'm still way rich somewhere.

Should I stay on the PJ and keep dropping it until I can get a higher idle? Or move to the needle or main jet?

I know that lean or rich the pipes still going to splooge until I repack it.






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check you jet block gasket.

it should be doing well if your pilot jet isn't blocked with 40-45 pilot
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Re: 96KDX Jetting help, Running rich

Postby KDXRipStick » 06:15 pm Apr 03 2018

ohgood wrote:
KDXRipStick wrote:Of course I had a magic genie give me the correct Jetting!

I swapped from 45PJ to 42PJ and couldn't get it to idle.

Swapped a 40PJ in and with the idle screw all the way in (Max idle) and the air screw 3 turns out.

It now idles but is extremely close to shutting off.

Throttle response is exceptionally improved but I'm still way rich somewhere.

Should I stay on the PJ and keep dropping it until I can get a higher idle? Or move to the needle or main jet?

I know that lean or rich the pipes still going to splooge until I repack it.






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check you jet block gasket.

it should be doing well if your pilot jet isn't blocked with 40-45 pilot


**** I never even thought about the jet block gasket.

The torx (assuming) heads on the bolts to my jet block look stripped as hell. Wondering if the jet block gasket is blown or not seated correctly.

I'm going for a quick rip through the woods shortly and then all take the carb off and start messing with it.

Probably going to order a carb rebuild kit tonight just to freshen her up.

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Re: 96KDX Jetting help, Running rich

Postby tmmyghst » 07:04 pm Apr 03 2018

The jet block gasket was key to getting mine and my buddies H models dialed in.
If it is passing gas ( pun intended ) it will always be rich.

To get it right you have to check everything.
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Re: 96KDX Jetting help, Running rich

Postby Jason » 07:07 pm Apr 03 2018

security Torx 20 I believe
Thank you, Julien D for all your hard work!

PLEASE! Do not "dip" PWK Keihin carbs in Berryman's to clean them! It will damage the internal o-ring (jet block gasket).
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