1990 kdx 200

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cowasaki
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1990 kdx 200

Post by cowasaki »

hi guys im new amd have just bought a 1990 kdx 200 runs good, needs some work but would like to start by learning what the stock or best a/f screw setting with stock jetting, also my clutch sticks ever so slightly ad will kill the motor if im sitting while im gear amy ideas i have played with the cable some but it really hasn't improved, thanks so much
-Cowi

lol... cam amy ome guess what key has stopped workimg om me? L-M-?-O-P
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SS109
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Post by SS109 »

Welcome to the forums!

The idle mixture screw should be adjusted for your conditions when you are riding. Things like temp, humidity, and elevation can change what is the optimal setting during any given ride. I suggest reading the jetting guide as it will give the run down on what you are looking for when adjusting the airscrew. Click the following link and read up! http://kdxrider.net/forums/viewtopic.php?t=1156
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Fletch
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Post by Fletch »

I would add to check the function of the powervalves by removing the pipe and having a look in the exhaust port. THere are three valves one in the center and two on either side of that. The e- series is known for breaking the l-hand sub-valve. You'll have to pull off the little plastic cover off the right side of the cylinder to get at the actuaton shaft (three 8mm bolts). They should open and close together when you pull the shaft in and out. This is also a good time to check the condition of the piston and to have a small look at the cylinder. If the piston is all scored up you might want to change it. I had one let go and it makes a big mess. Hope fully you are smarter than me and already know this...
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89 kdx 200 with 99 rm125 forks
cowasaki
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Post by cowasaki »

ehh this keyboard :mad:
thaks i will check the valves, i oticed the power kida cuts off at mid-high rpm this is my secod 2 stroke ad first oe with power valves so should this bike scream all the way thru the rpm's or are they made to oly have low ramge power at first i thought it was fime but ow i thik this might be a valve issue

also im at 1-1/2 turs out is this lean should i be like 2-1/2
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SS109
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Post by SS109 »

KDX's don't scream like an MX bike but it should pull/rev pretty good into the upper RPM's.

As for the airscrew, 1.5 turns is ideal if your pilot jet is correct.
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cowasaki
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Post by cowasaki »

well i had a look see in the exhaust, piston and what not looks clean, seen newer bikes that looked worse, right and left valves were working good except the top valve. i really dont know what it should look like but to me it looked like it would close shut if rotated anymore any pics of what they should look like would be appreciated, i did see that the pipe is missing its o rings so i guess its been off maybe a few times, could escaping gas at high rpm affect the powerband... it will certainly fix the splooge on my front fender :wink:

also i guess i should note its got some good dents in the pipe, as for jetting im at 500ft elevation and its about 70 degress fahrenheit all with i think is stock jetting
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Post by SS109 »

Sorry, I don't have pics of how the KIPS should look when installed. I'm sure someone on here either has some or knows where to find them. Dents in the pipe don't matter as long as they are not in the headpipe (first 12" or so). The jetting is something you just have to get into and do the way the jetting guide says. Every bike is different and so are the conditions that bike is ridden under.
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Current KDX: '98 KDX220
Old KDX: '90 KDX200 -White/Blue
'11 GasGas EC250R
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Post by chadr »

>|<>QBB<
cowasaki wrote:i did see that the pipe is missing its o rings so i guess its been off maybe a few times, could escaping gas at high rpm affect the powerband... it will certainly fix the splooge on my front fender :wink:
Even new orings on my bike didn't seal well so I followed the advice I had read on here about using a good amount of silicone sealer. I prefer permatex right stuff since it seals well enough in a few minutes that you don't need to let the bike sit at all. I started my bike 10 minutes after putting the pipe back on and it hasn't leaked yet 6 months later.
1989 KDX 200
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Post by cowasaki »

well guys i pulled the head off looks like its a pretty fresh cylinder :supz: but now i can see that top valve is completely timed backwards like it is a tiny bit open at rest, then when you pull the arm it turns but stays closed until the last little bit then it opens just a crack...

i have a petty good idea of how it works shouldn't need any pics, so how do i re-time the top valve so far i pulled the little access plate above the exhaust port but can't get to that valve
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Post by chadr »

bookmarked this site a while back

http://www.geocities.com/a57ngel/moto/kips.html
1989 KDX 200
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Post by cowasaki »

thanks man, at first i couldn't understand it but it actually helped alot hopefully ill have her all back to gather in an hour or so
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Post by cowasaki »

thanks again guys got her all back together and she runs so much better and quieter too :supz: chadr both the link and the silicone worked awesome but just a questions my idle has dropped super low now... i screwed the idle in all the way, like it sounds like its about to die but it sat and idled steadily for well over 30 seconds before i turned her off


one last thing is the clutch still doesnt want to let go its strong enough that if im in second gear and decide to coast down a hill it will bring my rpm's up and if i hit the kill switch it just keeps cycling over which kinda hurts my stealth, if i take off the clutch cover can i adjust anything in there
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scheckaet
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Post by scheckaet »

have you read this: http://www.kdxrider.net/forums/viewtopic.php?t=1156
that's all u need to sort the jetting now.
clutch dragging, I would guess the fingers basket have notches on them from the friction plates. Take it out and smooth them. do a search there is a post on how to do it, you can't be too aggressive on them, just wanna smooth it out.
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