KDX 200SR stock jetting

Discussion specific to KDX models not sold in the USA
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nick.killick
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KDX 200SR stock jetting

Post by nick.killick »

Hey all,

I've picked up a 1990 KDX200SR in the UK, done a top-end rebuild on it but I have a feeling the jets in the carb (28mm) are completely wrong. I've changed the pilot jet to 45 and can now idle it at least but I'm having a mission getting the main jet and needle position right.

Does anyone know what should be on here or can check on theirs to see what works as stock - then I can adjust as necessary for my machine?

Thanks!
HillbillySnowman
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Re: KDX 200SR stock jetting

Post by HillbillySnowman »

Where did you get your jets? Did they come in a kit?
Im trying to find a kit for the 28mm carb but havent found any yet.
nick.killick
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Re: KDX 200SR stock jetting

Post by nick.killick »

Hey Hillbillysnowman,

I bought a (relatively cheap) pack of pilot jets and main jets from ebay. As I don't know what the stock jets should be I bought a pack so that I can try tuning it as necessary. I found the 45 pilot jet worked quite well but still working on the main, needle and needle position.
SerpentZA
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Re: KDX 200SR stock jetting

Post by SerpentZA »

Mate, I have a turd SR I'm trying to rebuild and I can guarantee that the carb has never been repaired, I'll take a look on Tuesday and post some pics of what the jets look like

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nick.killick
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KDX 200SR stock jetting

Post by nick.killick »

As an update to anyone interested, here's the current situation:

I was really lazy getting this sorted over winter but been having another crack at it recently. I can get the bike running pretty reliably now, but at low end it's really rich and WoT massively lean to the point that in 6th gear the last 10% of throttle gives no power at all.

Pilot jet: 42
Main: 128
Needle: N68K, 2nd clip (from top)
Needle jet: Fitted at maximum height

If I put a larger main jet in it still runs lean, if I increase the needle height it runs FAR too rich at idle and up to half throttle. Dropping the pilot jet prevents it idling at all.

It's basically not doing what it should be doing, which is damn infuriating. I think I'll be removing the carb boot tonight to make sure there's no cracks/leaks which might explain why it's *SO* lean at top end.
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Jaguar
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Re: KDX 200SR stock jetting

Post by Jaguar »

there is a correct sequence to follow when jetting: http://www.dragonfly75.com/moto/carbtuning.html
Performance CDI -- KDX motocross mods -- the SR KDX -- expansion chamber analysis---> http://www.dragonfly75.com/moto/
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