Help w/1985 KDX200?

Discussion specific to the various air-cooled KDX models sold in the USA
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TigerKDX200
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Help w/1985 KDX200?

Post by TigerKDX200 »

Issue> stall at idle & sputter at low RPM, runs smooth in upper range

Troubleshooting & Results>
1. ran compression test & was near bottom of operating range (122 psi), installed used rings off eBay & got modest improvement in compression (133 psi)
2. thoroughly cleaned carb & installed new jets (stock size), needle is good, float/needle good
3. thoroughly cleaned air box & installed new filter
4. installed new plug
5. examined piston & cylinder, no significant wear
6. examined reed block/reeds, no issues
7. checked for air inleakage on intake side found nothing wrong
8. found exhaust gasket/rings degraded/gone so it has moderate exhaust leak between head & pipe (ordered parts...TBD after install if that helps issue)

Any suggestions what else can cause the stall/studder issue??
Thanks!
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6 Riders
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Re: Help w/1985 KDX200?

Post by 6 Riders »

Did you replace the pilot jet?
Other things to look at are float height, throttle cable, petcock and vent tubes.

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TigerKDX200
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Help w/1985 KDX200?

Post by TigerKDX200 »

Replaced pilot jet, replaced petcock, installed new fuel lines, removed & lubricated throttle cable. Did not check vent tubing, from memory there are 2 lines....will pull those & check. Not sure about float height, it's not adjustable that I can tell; no bendable tang like on my CRF450R. My exhaust gssket/O-rings arrive tomorrow as well. Thanks for tips, I'll keep chasing till it's solved.
david
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Re: Help w/1985 KDX200?

Post by david »

Never seen a non-adjustable float.
'81 KDX 175
'90 KDX 200
'07 Vulcan 2000 Classic LT (totaled 4/25/15)
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G22inSC
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Re: Help w/1985 KDX200?

Post by G22inSC »

Can't wait to see this one once you get it sorted out!
'05 Kaw KDX200 ('00 KX125 forks / '02 RM125 Showa "K2" shock)
'14 Yam YZ125(x) (oldest boy's)
'22 Yam YZ125X (youngest boy's)
'17 Yam YZ85 (soon to be FOR SALE)
'10 Honda Recon (wife's)
'08 Kaw KX65 (Sold)
'07 KTM 50SX Sr. (Sold)
'09 Yam PW50 (retired)
'97 Kaw KX250 (Sold)

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KDX Geoff
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Help w/1985 KDX200?

Post by KDX Geoff »

To eliminate the carb as the issue, fit a carb of another bike and see what it's like.
1980 KDX400-A2
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Help w/1985 KDX200?

Post by 1980 KDX400-A2 »

... installed used rings ...
Why used?
David
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Re: Help w/1985 KDX200?

Post by G22inSC »

1980 KDX400-A2 wrote:
... installed used rings ...
Why used?
Because that's all he could locate as OE rings (and aftermarket) are no longer produced.
'05 Kaw KDX200 ('00 KX125 forks / '02 RM125 Showa "K2" shock)
'14 Yam YZ125(x) (oldest boy's)
'22 Yam YZ125X (youngest boy's)
'17 Yam YZ85 (soon to be FOR SALE)
'10 Honda Recon (wife's)
'08 Kaw KX65 (Sold)
'07 KTM 50SX Sr. (Sold)
'09 Yam PW50 (retired)
'97 Kaw KX250 (Sold)

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2005 KDX200 Bike Profile
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Re: Help w/1985 KDX200?

Post by 6 Riders »

I could be completely wrong, but it would seem to me that newer kdx rings would work. The bore and design should be similar, no?

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Re: Help w/1985 KDX200?

Post by KDXGarage »

The ring end shape may be different? Different ID? ring actually thicker, taller??
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G22inSC
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Re: Help w/1985 KDX200?

Post by G22inSC »

6 Riders wrote:I could be completely wrong, but it would seem to me that newer kdx rings would work. The bore and design should be similar, no?

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That's what I originally thought as well. I'll let TigerKDX200 ring in with the details but long story short, he spoke with a Wiseco individual who stated it would not work and gave specific details of why and the current options available.
'05 Kaw KDX200 ('00 KX125 forks / '02 RM125 Showa "K2" shock)
'14 Yam YZ125(x) (oldest boy's)
'22 Yam YZ125X (youngest boy's)
'17 Yam YZ85 (soon to be FOR SALE)
'10 Honda Recon (wife's)
'08 Kaw KX65 (Sold)
'07 KTM 50SX Sr. (Sold)
'09 Yam PW50 (retired)
'97 Kaw KX250 (Sold)

Gallery

2005 KDX200 Bike Profile
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