1992 kdx200 jetting/idle

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darb808
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1992 kdx200 jetting/idle

Post by darb808 »

Did a compression test got 130 and 120 but the throttle was closed

checked my Reeds they look good put some gas in the cage and it leaked out very slowly

Repacked my silencer

I'm having trouble jetting the bike idle screw and air screw dont seem to do much

Idle screw all the way in doesnt raise idle gotta ctwist the throttle to make it idle

Air screw all the way closed will kill the motor but no noticeable change as i unscrew doesn't rev

Will try again later but was looking for ideas or things to check watch for.

Going to clean carb again. Trying to follow the jetting guide but stuck at the air screw step

Thanks guys
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Gotanubike
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1992 kdx200 jetting/idle

Post by Gotanubike »

What jets do you currently have? And your elevation? FMF or stock?

Factory carb settings are as follows(according to my manual)

Pilot - 48
Main - 158 or 150
Air screw - 1.5 turns out
Float level- 16mm +/- 1mm
Needle - R1172N, 4th clip from top

For me, the idle screw has almost no effect but my air screw is 2.5 turns I think due to rich(basically stock) 45 pilot
1990 KDX200
Bike Profile -> http://www.kdxrider.net/forums/viewtopi ... 61#p136315
Suspension Overhaul(Shock+89-92 conventional forks) -> http://www.kdxrider.net/forums/viewtopi ... 15&t=15255
96'-98' RM125 Showa 49mm fork swap -> http://www.kdxrider.net/forums/viewtopi ... 04&t=16994
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darb808
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Re: 1992 kdx200 jetting/idle

Post by darb808 »

Fmf gold series ? ill get the jet numbers elevation 800' it starts first kick is that rich usually?
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Julien D
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Re: 1992 kdx200 jetting/idle

Post by Julien D »

If the idle screw is not effective, it is likely that your pilot jet / circuit is clogged. Pull the carb, clean everything really well and blow out with compressor or canned air, make note of jet sizes, and re-assemble. Guitar strings make an excellent tool for cleaning out jets and little passages in the carb. As a side note, do NOT soak the carb in anything. There is a rubber seal between the carb body and jet block which can become damaged and leaky if soaked in solvent.
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darb808
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Re: 1992 kdx200 jetting/idle

Post by darb808 »

Will do another carb clean and float check ow will let you guys know results.

What do you think about my compression readings ? Does it matter that it wasn't wot?
Keystone
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1992 kdx200 jetting/idle

Post by Keystone »

It's recommended to be WOT but what difference it really makes, I don't know. From what I understand, kicking it over several times to bring the compression up to the highest reading possible is what is important. And, be consistent, when you re-check it after a rebuild, try to kick it that same amount of times.
I bought the bike with 1, 524 miles on the odometer, owner said he never replaced the piston or rings but was not the original owner, so who knows? Engine looked like it had never been apart.
I kicked mine over ('93 kdx200) a good 10 times straight before rebuild and got 150 psi.
usable range is 119-185 psi.
I kicked it over 10 times after rebuild and got 180 psi.
I also read that engine is supposed to be warm, mine was not. I was WOT during testing.
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Julien D
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Re: 1992 kdx200 jetting/idle

Post by Julien D »

The 10 PSI difference in your two tests doesn't add up. It should be consistent. Procedure is to disconnect the plug, hold throttle open, and kick until the gauge stops rising.
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darb808
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Re: 1992 kdx200 jetting/idle

Post by darb808 »

Ill redo it i think I did a a few extra kicks the first time thanks guys for all the info haven't had a chance to get to it yet. Ill let you guys kno.
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Gotanubike
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1992 kdx200 jetting/idle

Post by Gotanubike »

Aren't you supposed to hold the kill switch too?
1990 KDX200
Bike Profile -> http://www.kdxrider.net/forums/viewtopi ... 61#p136315
Suspension Overhaul(Shock+89-92 conventional forks) -> http://www.kdxrider.net/forums/viewtopi ... 15&t=15255
96'-98' RM125 Showa 49mm fork swap -> http://www.kdxrider.net/forums/viewtopi ... 04&t=16994
KDXrider world map! -> https://www.zeemaps.com/map?group=186158
MikeNZ
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Re: 1992 kdx200 jetting/idle

Post by MikeNZ »

Can't see why is not like it could start without the plug in?
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Gotanubike
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1992 kdx200 jetting/idle

Post by Gotanubike »

lol yeah but you can potentially fry the ignition coil / cdi unit I think
1990 KDX200
Bike Profile -> http://www.kdxrider.net/forums/viewtopi ... 61#p136315
Suspension Overhaul(Shock+89-92 conventional forks) -> http://www.kdxrider.net/forums/viewtopi ... 15&t=15255
96'-98' RM125 Showa 49mm fork swap -> http://www.kdxrider.net/forums/viewtopi ... 04&t=16994
KDXrider world map! -> https://www.zeemaps.com/map?group=186158
darb808
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Re: 1992 kdx200 jetting/idle

Post by darb808 »

adjusted float - was alittle low
cleaned pilot -48 - looked clean
cleaned main -150 - also clean
took out airscrew sprayed w/ carb cleaner
sprayed whole carb in/out w/ carb cleaner (outside before disassembly)

cleaned reeds and flipped them but it made a gap so i flipped it back.

tomorrow-

put back together
check slide
try jetting/again
re-check compression(holding kill switch and wot)
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