Q8: carb? problems 2001 KDX220

Discussion specific to the 1995 - 2006 KDX200 (H Series) and 1995 - 2005 KDX220R (A Series) models sold in the USA
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freeindeed
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Q8: carb? problems 2001 KDX220

Post by freeindeed »

I bought a 2001 KDX220 with roughly 1,250 miles on it and did a 6 month build.

It has a new Wiseco top end, power valve cleaned, RB designs head mod, stock carb, air box lid and snorkel intact, twin air filter w/ maxima FFT air filter oil, air box to air boot sealed, FMF gnarley woods pipe, stock muffler, two copper exhaust gaskets for more low end, stock reed valve in good shape, modified exhaust port, motul 710 two stroke oil mixed 40:1 using 91 octane non-ethanol gas, NGK BR8ES spark plug.

The carb came with a 145 main jet, 42 pilot jet, needle clip in 2nd position from top,
and the fuel shut off needle was not closing because the clip was not assembled onto the needle correctly.

Before breaking in the new engine I changed the jetting to stock: (145 main jet, 42 pilot, needle clip in 3rd from top position) and set the float level to about 15.9 mm and reassembled the fuel shut off needle and clip correctly. I sprayed all the orifices with carb cleaner. Everything looked in good condition.

After break in I changed the pilot jet to a #40 and reset the float level to about 16.5mm (so the fuel level is lower to insure the bike is not running too rich and will not leak out the overflow.

I just went on a trail riding trip Friday and Saturday. I found the bike leaks fuel out the overflow tube when it leans slightly to the left, but does not leak when it is upright or leans to the right. Also, when the bike warms up it pings at mid throttle as if there is a lean condition or running out of gas. So when riding I varied the throttle alot or ran it at lower RPM's to try to minimize the pinging.

So the plans are: order a carb rebuild kit and o-ring jet block from jets r us (even though the fuel shut off needle looks new), polish the fuel shut off seat, move the needle clip to the 4th from top position and maybe soak the carburetor in cleaner before replacing the o-ring jet block.

Does that sound like a good plan? Or maybe a new lectron carb would be a better solution?
Last edited by freeindeed on 02:15 pm Jul 03 2018, edited 1 time in total.
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Re: Q8: carb? problems 2001 KDX220

Post by KDXGarage »

I'd try changing the needle one clip, besides checking the float valve and level. Leaking fuel is a float, float valve or level problem.
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Q8: carb? problems 2001 KDX220

Post by lucy »

freeindeed wrote: Or maybe a new lectron carb would be a better solution?
Lots of guys riding orange have tried this solution and come up empty. Do your homework carefully before you throw several hundred bucks into a Lectron.
Last edited by lucy on 05:59 pm Jul 02 2018, edited 1 time in total.
freeindeed
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Re: Q8: carb? problems 2001 KDX220

Post by freeindeed »

Also, I just checked the spark plug and it is black & sooty with two stroke oil on the threads.
I talked to JD jetting briefly and they suggested do a leak down test.
Would not think that would be needed?
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Re: Q8: carb? problems 2001 KDX220

Post by bufftester »

For the leaking overflow try setting your float level to 18mm, that is a pretty common issue with these PWKs. Like Jason, I'd try raising the needle one clip to richen up the mid range, other option would be to try a needle one range richer. You did a top end, but did you do a leak down prior to disassembly to get a baseline? If not a leakdown would be a good check, though your issue doesn't sound like a leaking crank seal but more a carb setting as you made quite a few changes to the intake/exhaust track.
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Re: Q8: carb? problems 2001 KDX220

Post by SS109 »

bufftester wrote:For the leaking overflow try setting your float level to 18mm, that is a pretty common issue with these PWKs. Like Jason, I'd try raising the needle one clip to richen up the mid range, other option would be to try a needle one range richer. You did a top end, but did you do a leak down prior to disassembly to get a baseline? If not a leakdown would be a good check, though your issue doesn't sound like a leaking crank seal but more a carb setting as you made quite a few changes to the intake/exhaust track.
Yup!

Also, OP, you didn't state what needle you're actually running. Some are better than others.
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freeindeed
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Re: Q8: carb? problems 2001 KDX220

Post by freeindeed »

bufftester wrote:For the leaking overflow try setting your float level to 18mm, that is a pretty common issue with these PWKs. Like Jason, I'd try raising the needle one clip to richen up the mid range, other option would be to try a needle one range richer. You did a top end, but did you do a leak down prior to disassembly to get a baseline? If not a leakdown would be a good check, though your issue doesn't sound like a leaking crank seal but more a carb setting as you made quite a few changes to the intake/exhaust track.
I ordered a PWK33 "rebuild" kit for $35.
In the meantime, I will raise the float level to 18 mm and move the clip to 4th from the top & try to take a test ride this week.
No, I did not perform a leak down test prior to doing the top end. So if a carb rebuild & jetting does not help, then I may have to have that test done.
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Re: Q8: carb? problems 2001 KDX220

Post by freeindeed »

YUP!

Also, OP, you didn't state what needle you're actually running. Some are better than others.[/quote]

The needle is probably the stock one, but I will check it and post the ID#.
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Re: Q8: carb? problems 2001 KDX220

Post by freeindeed »

The needle is a R1173L. I just moved it to 4th clip position from the top.
About a 1/4" area in the middle of the needle the surface is rough with some scratches and pitting.
I am guessing the rough area probably won't affect how it runs.
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Re: Q8: carb? problems 2001 KDX220

Post by freeindeed »

OK I have a partial update.
1) I installed a new Keihin carburetor kit #020-110. This includes airscrew & spring; carb. top gasket; float drain o-ring; needle valve/pivot pin/needle spring and plastic end for throttle slide spring. I did not install the float bowl gasket because the new one appeared to be smaller than the one in there (probably original one.)
2) I set the float level to a range of 17.8mm-18.3mm from 16.5mm.
3) I moved the R1173L needle to 4th clip position from top (from the 3rd position).
4) I added a reed valve gasket toward the carb side instead of relying on the reed valves rubber ridges.
5) Installed a new gas line
6) Installed a new NGK BR8ES spark plug

I tested the new setup in a paved Church parking lot for about a half an hour. It ran MUCH better.

1) I no longer noticed pinging in the midrange. It seems very fast and revs quickly through the power band. At any RPM you can twist the throttle wide open and it does not bog or stumble. But this made It seem slightly lean. I say this because of how quickly it revs through the power band made it feel like there is a hit at midrange perhaps at roughly 5000 RPM's. And at roughly 8000 RPM's the top end seems to make a little noise, like maybe a slight chatter or knock? But I know the cylinder to piston clearance is .003" with the new wiseco piston, whereas the original piston clearance was .004".
2) There is a now a rich running condition at the real low revs. It stumbles/blubbers at steady throttle at low revs or accelerating through lower revs.
So I turned the air screw out to 3 turns out and the idle increased and it ran better through low revs although it still had some stumble/blubbering. Now the bike actually idles when it is hot and you come to a sudden stop with the bike in gear and the clutch pulled in.
3) The float bowl no longer leaks fuel out the overflow tube when the bike is sitting on its kick stand. Now it doesn't leak until the bike is leaned to the left about 15 degrees. So a improvement there too.

This testing was in a paved parking lot, so not in off road conditions, so I may not fully know how it will run there.

Nevertheless my thoughts now are:
1) Change to a 38 pilot jet to lean out the rich sounding condition on the low end and try it off road.
or
2) Change to a 38 pilot and go 1/2 clip richer or maybe even a full clip richer on the needle to smooth out the midrange hit.
Last edited by freeindeed on 06:12 pm Aug 02 2018, edited 1 time in total.
John_S
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Re: Q8: carb? problems 2001 KDX220

Post by John_S »

I'm glad to hear you're getting there. Sometimes a too rich pilot going to a clean needle can make it feel like it has a hit. When the pilot is fully dialed and snappy the transition to midrange might feel smoother. I would concentrate on the pilot and air screw (with the 38) and not tune the needle until it's crisp at 0-1/4 throttle.
freeindeed
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Re: Q8: carb? problems 2001 KDX220

Post by freeindeed »

I agree, one change at a time is the best strategy for jetting, good post.
But with time deadlines for upcoming rides/races and weariness from testing jetting/sometimes washing bike/removing carb for yet another jetting change, I opted for multiple changes.

Therefore I prayerfully made these changes:

1) New 38 pilot jet as you suggested (previously 40)
2) I moved the R1173L needle to 5th clip from top (previously 4th clip from top). (The last time I installed a leaner pilot jet, it caused the midrange to become lean and cause more pinging which was solved by moving the needle one clip richer. Therefore if the same pattern repeats itself, I MIGHT save myself an extra jetting change by richening the needle one clip position while simultaneously leaning out the pilot jet. It makes some sense considering the RB head mod and the exhaust port modification may have changed the flow of the intake and exhaust. Needing more fuel at midrange and less at idle seems reasonable. The jetting seems slightly lean at midrange and full throttle anyway.)
3) New jet block gasket from JD jetting.

I will try to test these changes within the next 4 days.
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Re: Q8: carb? problems 2001 KDX220

Post by freeindeed »

I was able to test the '01 KDX220 this morning.
I warmed it up for 5 minutes and rode it for 10 minutes on a tar parking lot.

Results:
1) It runs good when I am really on the throttle. At any RPM you can twist the throttle wide open and it does not bog or stumble.
2) There is still a rich running condition at the real low revs. It stumbles/blubbers at steady throttle at low revs or accelerating through lower revs.

So it appears I need to try a 35 pilot next and leave everything else alone?
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