Perk

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Sep 17, 2001
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2002 KDX 220, FMF Rev, Q Silencer, Frisbee removed, RB carb mod running jetting that was installed in carb from RB.

Today while riding tight off road terrain the bike started to bog badly in the upper end of RPM range, 3/4 throttle and above. No problem anywhere else in power range until a little bit later in the ride. Bog got worse later on in ride and started to appear in lower throttle untill bike just stopped running. Tried new plug with no luck. Checked vent tube on top of tank and breathing fine. Still appear to have good compression but bike will not refire. When it cut out, it acted if out of gas, but there was plenty in tank. Yes, the petcock was on. Even tried reserve but nothing. I'm thinking trash in carb but I am not the best at diagnosing issues with the bike.

Fire away.

Thanks,

Perk
 

BSWIFT

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N. Texas SP
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Nov 25, 1999
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Disconnect the fuel line from the carb and drain some into a container. If it flows good, remove your carb and clean thoroughly. It sounds like you have some blockage and your starved for fuel.
 

Perk

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Sep 17, 2001
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Thanks for the feedback BSWIFT. That's along the same lines as I was thinking, but I trust a lot of you long time DRN members more than myself when it comes to these issues. I'm pretty good with a wrench, but don't have a lot of confidence in my thoughts as to what's wrong. If anyone else has a different potential diagnosis, I'm all ears. This site and this forum in particular have never let me down. Thanks again.

Perk
 

OldDirtKDX

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Dec 14, 2004
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Stator

Had a similar problem a while back. Turned out to be the stator failing. Shop Manual has to specs to test it if the fuel system checks out.
 

Perk

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Sep 17, 2001
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More good feedback. Preeschateya OldDirt.
 

Perk

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Sep 17, 2001
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No, not yet. I've never had to check before, so I'm not sure how to do it. Someone please refresh me. I've seen it done but it's been an eternity since. I pulled the carb today but did not have time to tear it down and clean everything out. I could definitely see a little bit of very fine funk and gunk in there. I guess it is just stuff that made it's way through the air filter over numerous rides. I keep the bike pretty clean, but do not keep up with routine maintenance like I should. I keep fresh tranny oil in it and clean the filter pretty regularly, but I get pretty lazy after that.
 

low_e

Member
Mar 27, 2007
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/\ Remove the plug from the head and put it back in the boot. Now lay it on a conductive metal part of the bike (frame, pipe, etc.). Kick it over with your hand a few times and you should see a spark. Don't hold the plug against the metal with your free hand or you'll get zapped, just let it lay against it.
 

KdX_SkUiRrEl

Member
Oct 28, 2006
47
0
check your airfilter also. dirty filter, or over oiling is a very common problem i see on dirtbikes when they come into the shop. if in doubt just clean and reoil it. it wouldnt hurt to do it anyways ;P happy riding
 

BSWIFT

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N. Texas SP
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Nov 25, 1999
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I forgot to mention to check your float level. Too low and it will starve for fuel.
 

Perk

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Sep 17, 2001
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Would the float level be an issue over that short of a time span? The bike went from perfect to just having a lean bog near redline within about a minute. Everytime I would get the revs up, the bog would come down further and further in the RPM range, until it reached the midrange, then it just went kapoot. This all took place from start of problem to dead in about 20 minutes. Got into the carb today and main jet and pilot appeard to have some degree of blockage. Kind of hard to see in those tiny holes though. After some carb cleaner the jets looked perfect though.

I am a bit confused though about setting the float. Was looking at the float tip on the JUSTKDX site and can't figure out what they are referring to as the float bowl mating surface. I could not find what I would call a mating surface. I get everything else in the instructions but that. Is he referring to the surface where the float bowl and the upper half of the carb meet? That makes sense to me, that's probably it. Can anyone confirm that for me? If that is it then I'm going to definitely have to bend that tang on the bowl pivot thingy. Mine is not even close to level when it meets that little actuator pin thingy.
 

Perk

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Sep 17, 2001
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paab also mentioned above to check reeds. Forgot to mention that I have a V-Force II installed. Have not yet checked reeds. That would have been a nice post to have read before re-installing the carb today. :bang:
 

Perk

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Sep 17, 2001
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Scoring of the cylinder I can see, but other than that how do you know if it is about to granade? It did not run lean for long, when the bike would start to bog I would bring down the revs immideately into the midrange where it was running fine. I'll give a look anyway while the seat and tank are off. Thanks,

Perk
 

Perk

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Sep 17, 2001
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It's a Weisco. Fairly new top end. Has maybe 40 hours on it. I ditched the OEM after reading all of the horror stories.
 

Perk

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Sep 17, 2001
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OK. Here I go again. Since I had already cleaned out the carb and re-installed it, I decided to put a gallon of fresh gas in it and just see where I was at. It fired on about the third kick but died out in about three seconds. I gave up after about 50 kicks in 90 degree heat. Fresh filter, clean carb, fresh gas, new plug and I did check for spark and I have one. Not only can I see it, I can hear it. Pulled out plug and it was pretty wet all around. Is float level my next step. If I was looking at it right, then it is quite cockeyed to the up direction, as the carb would be sitting on bike.
 

Perk

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Sep 17, 2001
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I take that last statement back. With carb upright, it was actuating the little plunger on the float needle at a below level position. When I say level, I'm referring to the float bowl mating point. That would have pushed the plunger thingy in further, delivering more fuel and potentially flooding the bike. Right? Would flooding have caused the bogging that started this whole fiasco?
When I removed plug after last start attempt, it was pretty wet. And after removing carb again it was pretty wet also going into the reed cage. I pulled off the float bowl and bent the tang so that the float now actuates the needle when level. I don't have the measuring tools, so I did it by eye. Either way, the float is WAY closer to level than it was before doing this.
No time to re-install and try again. Time to go to work. Looking forward to reading some posts when I get in from work this evening.
Thanks again for everyones help.

Perk
 

Perk

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Sep 17, 2001
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The more I think about the float level, the more confused I get. With carb upright, if the float contacts the needle below level, is that allowing more or less gas in bowl? After my adjustment on the float level, the float contacts the needle higher up in the bowl and is not depressing the pin on the needle as far as before. The float looks dead level when that pin starts to compress in the needle. Zat sound right?
 

Perk

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Sep 17, 2001
303
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And the award goes to "paab". It's taken me a while to get to this point as I have very little time anymore to work on the bike. Finally I get to the V-Force intake and KABLOOM!! Two reeds were completely blown into the reed cage and had partially damaged the other two reeds on that side of the cage. Have reeds on order but could not find the replacement gaskets that go on either side of the cage. Ordered from Dennis Kirk, but the only gaskets they had pertain to the top end. Gaskets still look in good shape, but I don't trust looks. Anyone know where to get those gaskets?
 

Perk

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Sep 17, 2001
303
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Found the gaskets at Bikebandit.com. Remembered someone had recommended that site on different post. Service seems great so far. Thanks to all.

Perk
 
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