KDX Acting Up

Brian

Stanbagger

N. Texas SP

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May 1, 2001

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• Nov 10, 2002

• #1

The last two times I've been out riding, my bike(97 KDX 200) starts acting up at totally random times. For some reason, it decides to act like it's running out of fuel. It will start to rev up, bog down with any twist of the throttle, surge, and die. It does this sometimes with a full tank of fuel. Position of the fuel tap(on, res, off) makes no difference. Carb is set up properly(float level, jets, AS, etc...) and again, this happens at totally random times. The previous owner told me that for some reason(I forgot his reasoning) he beat on the carb with a hammer, and this is obvious, as there are many scratch marks, and dings on the side of the carb. I've checked the petcock and fuel filter, neither one appear to be clogged. When this happens, there is fuel in the fuel line, so that indicates something is amiss in the carb, right? Any insight is apreciated.

 

R

rethnal

~SPONSOR~

Jul 14, 2002

659

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• Nov 10, 2002

• #2

Hmmm... happened to me too! Last time I was out.... I thought maybe it was a kinked breather hose. :silly:

 

Last edited: Nov 10, 2002

Brian

Stanbagger

N. Texas SP

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May 1, 2001

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• Nov 10, 2002

• Thread starter
• #3

The last two times I was out, it was extremely muddy. Maybe the breather hoses were getting clogged with mud? There was about an inch of mud accumulated on them last time, but I didn't check the time before. I hope that's it. Canyncarvr is knowledgable with these kind of situations. Maybe he could input some?

 

M

Matt90GT

Member

May 3, 2002

1,517

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• Nov 10, 2002

• #4

First thing to do is replace all the breather hoses on the carb. Also take the airfilter and clean it. Inspect the airbox boot behind the filter to make sure that no dirt is coming through the seal at the airbox. If it is, good chance that you are getting some dirt in the carb and jets. Last thing is to take the carb off and clean it!

 

J

jmutiger

Member

Oct 10, 2001

169

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• Nov 10, 2002

• #5

I've had that happen.. And each time it was carb icing.

I'd drain the fuel in the carb, get rid of any water in your fuel (it sinks to the bottom).. And try again on a warmer dryer day.

Jon!

 

B

BRush

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Jun 5, 2000

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• Nov 10, 2002

• #6

Clogged carb breather tubes will do this, as will a plugged gas cap vent.

 

J

John Harris

Member

Apr 15, 2002

552

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• Nov 11, 2002

• #7

Periodically you need to take the plug out of the bottom of the carb and drain it. Sounds silly, but water or condensate will collect there and bike will run funny or maybe cold not start at all. Always open the fuel petcodk and run a little fuel out when you do this to rinse out any trash, etc. that might accumulate in the bottom of the carb. Stan, you need to come to Barnwell Mountain in East Texas to ride where it is not muddy!

 

F

FLBob

Member

Jun 4, 2001

210

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• Nov 11, 2002

• #8

If the last owner "tapped" on the side of the carb, he was probably trying to release a hung-up float/needle valve. I'd suggest a real close look at those parts when you open up the carb to give it the good cleaning it probably needs.

 

C

canyncarvr

~SPONSOR~

Oct 14, 1999

4,005

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• Nov 11, 2002

• #9

re: plugged stuff.

Yep.

re: tapping and flbob

He's related the 'fix' to the 'problem'. Sounds good to me.

It's not too hard to tweak the floats when the bowl is put on. Just because the float level is judged to be correct doesn't mean the individual floats aren't bent some....so they hang up on the edge of the bowl?

But the hung-up inlet valve sounds good. Sounds especially good cuz I've had that same problem on two other machines in the past six months, and these things all run 'round in packs.....right? ;)

If new vent tubes/check valves don't fix it, check the lateral float alignment, replace the inlet valve and burnish the seat a bit with a strip of wet-n-dry over a q-tip.

Oh..make sure your carb is 'straight' as in alignment to the intake boot. The OEM boot has a notch that makes this pretty easy. Some aftermarket boots (boyesen) do NOT have that notch..and you can have the carb pretty crooked.

BTW...'Knowledgable' once in awhile, IMO everything else!

CONSIDER THE SOURCE

 

Brian

Stanbagger

N. Texas SP

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May 1, 2001

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• Nov 11, 2002

• Thread starter
• #10

Thanks for all the help, guys :) I assume that my carb is on right, float levels are correct,etc... because, well, someone who knows much more than me did it. At DW, Mikeb set everything up for me, and cleaned out the carb,too. I checked yesterday, and think I found the problem. Two of the three carb breather hoses were clogged solid with mud. I'll drain the carb,too, and perform all other suggested tasks to insure I don't have other problems,too :)