Kdx220 stops increasing rpm at 1/2 throttle - kips issue

Discussion specific to the 1995 - 2006 KDX200 (H Series) and 1995 - 2005 KDX220R (A Series) models sold in the USA
tmosely1
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Kdx220 stops increasing rpm at 1/2 throttle - kips issue

Post by tmosely1 »

I could use some thoughts on this one. I have a 97 kdx220 with 130psi of compression and a carb that I've been thru now several times. The float has been set by the air blow and angle method and it has a 38 pilot and 145 main 1172 needle with the air screw at 1-1/2 but (note that the screw doesn't appear to change anything.) I opened the inspection cap and the kips valve moves. I have confirmed that fuel flows freely thru the petcock. I have done a crankcase leak down and found no leaks. The bike starts right off and runs but doesn't idle without the idle screw all the way in and the rpm does not increase past half throttle. It runs great to the 1/2 throttle point lifting the front tire with ease. But then after you reach the 1/2 throttle point it doesn't increase in rpm from there. I have attempted the cdi test from the manual and cant duplicate the procedure. It mentions several times to use the Kawasaki meter but it is unobtainable. I can complete the coil test and it is either incorrect, or I don't get a reading on my secondary coil. The resistance on the exciter is good. Anyone have any ideas? Or know what would happen if I had a break in the secondary coil? I really feel like it ignition related.
I have tried the knocking the silncer with a mallet but haven't tossed it into a fire like I have heard guys suggest. I did consider this and pulled the silencer to see if it it would change the condition at all. I didn't ride it like that, but it made no change to the rough idle with the idle screw having to be screwed all the way in to even keep an idle. Reeds are new and while they don't hold crankcase pressure, I can hear them slowly leak back when I did the crankcase pressure check. I have tried 38-40-42 with 145-148 and 3rd and 4th clip with zero changes
Last edited by tmosely1 on 02:57 pm Apr 14 2019, edited 1 time in total.
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Re: Kdx220 stops increasing rpm at 1/2 throttle

Post by KDXGarage »

How is the power valve system?
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Re: Kdx220 stops increasing rpm at 1/2 throttle

Post by tmosely1 »

KDXGarage wrote: 03:25 pm Apr 11 2019 How is the power valve system?
Just completely cleaned, lubed, and reassembled. I have also had that side cover off once already to look at it to reassure myself that it is correct
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Re: Kdx220 stops increasing rpm at 1/2 throttle

Post by bufftester »

IF the intake track is mechanically sound (no air leaks, cracks in gaskets/boots, clean filter, new plug) and the exhaust track is also mechanically sound (KIPS, no blockages in silencer, etc) you likely have a carb issue, especially given that you have to run your idle screw all the way in and your airscrew is making no difference. Pull and clean the carb (don't dip it) thoroughly. You may want to check the jet block gasket while you're in there. Then run through the jetting guide and never change more than one thing at a time. The air screw should definitely change things as you move it from 1/2 to 2 1/2 turns out. You might also want to verify that your slide is traveling all the way open when you twist the throttle. If it runs then likely not ignition related, since it runs. Good luck and let us know what you find.
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Re: Kdx220 stops increasing rpm at 1/2 throttle

Post by KDXGarage »

If you looked in the manual to time and reassemble the valves, what version of the manual did you use? first and second versions have them backwards
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Re: Kdx220 stops increasing rpm at 1/2 throttle

Post by tmosely1 »

KDXGarage wrote: 09:43 pm Apr 11 2019 If you looked in the manual to time and reassemble the valves, what version of the manual did you use? first and second versions have them backwards
I have the first version.. but noticed it was janky... so I used one of the threads online that walks thru it. All is aligned correctly and the dot on the arm is on the white tooth of the actuator. I removed the pipe and confirmed the valve is closed while not running and rotating the actuator opens it.
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Re: Kdx220 stops increasing rpm at 1/2 throttle

Post by tmosely1 »

I made a little progress last night after disassembling the carb to check the jet block for leaks. (It was fine) I put a little fine valve compound on a q tip and worked a bit on the seat. I then flipped the needle clip direction and goofed with the float level again and I seem to be getting somewhere. ... I went ahead and ordered a new fuel needle valve. With the idle rough, lack of reaction from the air screw, and it seeming to load up and get smokey... It has to be getting past it somehow even though it seems to be fine when I test it. I have heard guys talk about buying needle seats for that carb, but I can't figure out where they sourced them... anyone know a vendor?
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Re: Kdx220 stops increasing rpm at 1/2 throttle

Post by bufftester »

For the PWK there are no commercially available needle seats, some folks have had luck doing what you did - a little polishing compound on a q-tip and patience. If its really bad your only real option is to replace the carb (and not with a chinese clone unless you REALLY like exasperation). However, a leaking inlet valve isn't going to keep it from running past half throttle, rather it would likely leak a lot out the overflow tubes and possibly flood the motor if it was extreme. The Idle air screw and the mixture screw are on the idle/slow circuit which does have some small passages in it. That's why we always recommend a thorough cleaning (without dipping which WILL destroy your jet block gasket) with spray carb cleaner and compressed air. Some folks even use very fine wire to run through the passages. Doesn't take much to plug one of them up.
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Re: Kdx220 stops increasing rpm at 1/2 throttle

Post by KDXGarage »

Just a needle valve, the seat is the carb body. If it is the original carb, then it is from 1996. They do wear over time.
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Re: Kdx220 stops increasing rpm at 1/2 throttle

Post by tmosely1 »

Think I found it... once the kips valve opens... its not closing... one blip and I am open ports
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Re: Kdx220 stops increasing rpm at 1/2 throttle

Post by doakley »

Try cleaning it first to see if it releases?
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Re: Kdx220 stops increasing rpm at 1/2 throttle

Post by tmosely1 »

doakley wrote: 01:17 pm Apr 13 2019 Try cleaning it first to see if it releases?
Tried.. No luck. Took of the side cover and checked the go enter and its assembled correctly and appears fine. I did notice the lever on the arm that rides in the bearings on the govener side is a touch loose and not rigid to the arm. Is it supposed to be rigid fixed to the arm? Going thru everything it's almost like the ball detent is to tight in the cylinder and dragging. I found where guys have removed that ball, but I'd rather figure out the issue rather than bandaid it.
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Re: Kdx220 stops increasing rpm at 1/2 throttle

Post by doakley »

Sounds like you're going to have to pull the cylinder, disassemble and do a proper cleaning/inspection. Not hard to do. Let us know what you find.
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Re: Kdx220 stops increasing rpm at 1/2 throttle

Post by tmosely1 »

To you guys that know these bikes better.. How much tension should there be when actuating the kips valve? There's a definite break over force required to get past the detent ball in mine. The issue I have is that something is holding it open once it gets past the detent. I am see it start to ruturn, but it doesn't have the force to make the full return... I'm thinkin it's in the actuator arm somewhere.
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Re: Kdx220 stops increasing rpm at 1/2 throttle

Post by tmosely1 »

So the kips valve opening and rotational pressure is controlled by the detent ball and spring. Mine already has a pair of copper washers to shim it out. Is that oem correct?
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Re: Kdx220 stops increasing rpm at 1/2 throttle - kips issue

Post by tmosely1 »

Schematic and manual seem to confirm that is correct... Anyone have any idea what the oem thickness is? Possibly they have been over crushed and are providing too much drag?
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Re: Kdx220 stops increasing rpm at 1/2 throttle - kips issue

Post by B737driver »

I have run mine without the ball in the past and I see very little difference in performance. I don't think that this is your issue. If the valves are timed correctly it's gotta be your carb. FWIW. I'd check the timing on the stator plate as well.
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Re: Kdx220 stops increasing rpm at 1/2 throttle - kips issue

Post by rexemouse »

I just did my 220 and mine has 2 washers. The detent definitely adds some initial resistance.

If your cylinder was just plated, the power valve rod bores can become really rough. I gently honed mine with a drill and some fine grit sandpaper, and this really smoothed things out.
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Re: Kdx220 stops increasing rpm at 1/2 throttle - kips issue

Post by rexemouse »

If you decide to pony up and buy a carb, consider going up to a pwk35. Big upgrade on the 220 IMO.
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Re: Kdx220 stops increasing rpm at 1/2 throttle - kips issue

Post by KDXGarage »

I concur with what texemouse said.

I know if someone who had an issue like that.
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