I finaly found the time to work on my new KDX200

Discussion specific to the 1989 - 1994 (E Series) KDX200 model sold in the USA
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StangerGT
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I finaly found the time to work on my new KDX200

Post by StangerGT »

A few weeks ago I bought a poor running 91 KDX200 that needs wheel bearings, fork seals for a song. The bike ran rough, it had very little power, it would constantly stall, was hard to start after it stalled and would stop idling after it warmed up. However, it seemed to start fine when cold and would idle fine until warm. So the first thing I did was pull the carburetor and found a bent float and that the pilot jet was clogged. I cleared the jet bent the float straight and tried to put the carb back together when I noticed it wasn't fitting together correctly... there was some kind of obstruction keeping the float bowl from fitting to the carb body. It could be pushed together with some pressure, but there was definitely something in the way. So i took a closer look at the float bowl and found that the overflow tube was bent and pushing up against the floats and preventing them from moving. It is also the reason the floats were bent. So I bent the tube back and the floats move freely. I also noticed that it has a 158 main jet and a 48 pilot. In the manual it should be a 160 main and a 48 pilot. The bike has an FMF gold series pipe and I am unsure if this is the proper jetting for this pipe. I also found the needle pin clip was moved down one notch from stock. I moved it back up to the stock location and put it all back together. I swapped out the plug for a fresh one and it fired up and ran a lot better.
I took the bike for a ride and it keeps idling now when it warms up, but it still seems like it lacks in low end power... like it seems flat in first gear, but surges a bit in second. Now, I haven't been on a dirt bike since I was a teenager so I forgot what its like to ride one and don't know what to expect as this is my first KDX, I have been riding a two stroke triple Kawi H1 500 and a modified Yamaha R5 350 (two stroke twin) as my daily rides for the past 4 years and am accustomed to how they react to a snap of the throttle in the first 3 gears. The KDX almost feels like the jetting is wrong or something. I cant tell for sure, but something doesn't feel right. Is the jetting correct for the pipe?
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Re: I finaly found the time to work on my new KDX200

Post by KDXGarage »

Jetting requirements will change based on altitude, humidity and temperature.

I think 158 was the stock main jet for 1989, but it went to 150 after that.

How's the air filter?

8 range plug?
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Re: I finaly found the time to work on my new KDX200

Post by StangerGT »

So I pulled the reed cage today and found a warped reed that is beyond the .2 mm service limit according to the manual. Ill replace it as it doesn't look like I can flip it. I also took a look at the air filter which is gooey and I imagine pretty clogged up. I'm guessing that its part of the issue. I think Im going to try to clean it, but will order a replacement as it seems a little crumbly in spots.

If 158 was stock for a 1989, I wonder if the carb or engine are from an 89 model? Ill try to get a number off of the engine. The frame badge indicates its a 1991.

I live in Minnesota and weather conditions change drastically from day to day which makes jetting a pain. Today is hot and humid, yesterday was cool and dry. The plug Im using is a NGK B9ES. Its the type that was in the bike, but the manual calls for a NGK BR8ES...
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Re: I finaly found the time to work on my new KDX200

Post by bufftester »

Run a BR8 plug, new filter, new reeds and check any other possible issues in the intake/exhaust track (i.e.: air leaks at any of the rubber boots, pipe to cylinder gaskets intact, no major dings/holes in expansion chamber, silencer drained and/or repacked if applicable. Then you'll be ready to check your jetting. Wouldn't be a bad idea to do a compression and leakdown test to check the condition of the motor as well, given the hidden gems you've already found.
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Re: I finaly found the time to work on my new KDX200

Post by KDXGarage »

What did you pay for it?

Yes, a properly running bike will need an "8" plug, a proper filter and good condition reeds.

Jetting is jetting.
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I finaly found the time to work on my new KDX200

Post by SS109 »

Jason and bufftester covered it all. I'm just here to beg for you to start a thread, with pics, in the "Other Bikes" section on your R5 and H1!
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I finaly found the time to work on my new KDX200

Post by StangerGT »

Thanks everyone for the information. I did a compression test and think I need to do a top end job. It's 140 psi and I think I need to be around 150 plus. Where would you guys recommend ordering parts from?

Also, I'll start a forum for my other bikes when I get a chance :cool:
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Re: I finaly found the time to work on my new KDX200

Post by KDXGarage »

oemcycle.com is where I got my last couple of Wiseco pistons. Check their prices. Rocky Mountain otherwise.
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Re: I finaly found the time to work on my new KDX200

Post by Rather be Riding »

StangerGT wrote:Thanks everyone for the information. I did a compression test and think I need to do a top end job. It's 140 psi and I think I need to be around 150 plus. Where would you guys recommend ordering parts from?

Also, I'll start a forum for my other bikes when I get a chance :cool:

I thought 140 psi is within the acceptable range. Cyclepedia states 90-151 psi. My 93 KDX 200 is at 130 psi with a new top end. It runs mostly fine.


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Re: I finaly found the time to work on my new KDX200

Post by KDXGarage »

How in the world do you only have 130 from a new top end??

Welcome to kdxrider. (7 months ago)
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Re: I finaly found the time to work on my new KDX200

Post by Julien D »

After my last top end job which included a replate I was pushing near 180psi. 150 should run fine, though. Have you checked the KIPS valves? If one or both is broken it can really affect your low end. Pretty common failure on the E bikes.

The 158 main should be fine as a starting point. After jetting you'll likely end up even smaller.
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I finaly found the time to work on my new KDX200

Post by StangerGT »

Ok so I think my compression tester may be incorrect. Im getting 145 psi now with it and did nothing with the engine. I did another test with a friends compression tester and got 152psi.. Im going to go with his over mine. A top end will be in this bikes future (probably over the winter), but for now I think Ill run it.

I ended up replacing the plug with the correct one and cleaning the air filter and it seems a lot better now. I'm still trying to find a new reed petal for it to replace the warped one.

Ill check out the KIPS system as well this weekend. I noticed someone must of been in there at some point because it has a bunch of rubber silicone form-a-gasket squeezed out the bottom of the KIPS cover.

Also, I was riding around my neighborhood the other day on my H1 and a guy in a truck followed me back to my garage and told me that he is a huge motorcycle enthusiast and lives at the end of my block! He goes dirt biking regularly on Sundays and knows where all the tracks, trails and etc are around my area. I just moved here in the spring and am happy to know I live practically next door to another motorcycle gear head! :supz:
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Re: I finaly found the time to work on my new KDX200

Post by Rather be Riding »

Jason wrote:How in the world do you only have 130 from a new top end??

Welcome to kdxrider. (7 months ago)

I suspect it's a little low because the cylinder wall has a little bit of wear/damage. I've got maybe 3 hours on this new top end. I made sure to clean out the KIPS and reinstalled them correctly so everything was actuating smoothly. I cleaned the hell out of everything.

Bike cranks up within a couple of kicks on the first start of the day. Only problem now is once she's hot and I kill the motor, she won't start again until I give her some time. I'll post elsewhere to get some help. I don't want to hijack the thread.
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I finaly found the time to work on my new KDX200

Post by StangerGT »

I got the bike running well enough to take light trail riding with a friend, but it just never seemed right. It still lacks bottom end and so when I got home I took the KIPS covers and the exhaust pipe off to take a closer look at the drum valves. Am I supposed to be able to pull the rod on the throttle side of the engine out while it is still hooked up to the bottom end? I pulled it out and while looking through the exhaust port, I saw one drum valve move as it should while the other one didn't move at all. I can turn the other valve by hand and it moves freely, but doesn't move with the rod. I also didnt see any slides moving to change port height. Im assuming the KIPS in my bike needs a rebuild. Any recommendations for parts? Ive heard these are tough to find these days.
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Re: I finaly found the time to work on my new KDX200

Post by david »

Not hard to find, just a little expensive. The valves are no longer offered by Kawasaki, but that’s ok as we have a better option now. BDK Racing makes steel replacements, about $200 USD. Several of us have bought them and are very pleased. Your center valve is probably fine (and not available new), you were just at the wrong angle to see it.


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Re: I finaly found the time to work on my new KDX200

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Thank you for participating on kdxrider.net. :bravo:
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Re: I finaly found the time to work on my new KDX200

Post by david »

Oh, man. I think his price came down a little.
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