My Baby Won't Start - Please Help

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Re: My Baby Won't Start - Please Help

Post by 6 Riders »

You should start at the tank.....is your tank vent plugged? Are you out of gas (or only have reserves left & the petcock is turned the wrong way)Is the petcock working, is the fuel line ok? Pull the Carb drain and see if there is any crud in the bowl and if fuel flows freely with the petcock on. Carb vent lines blocked? Air filter is clean and NOT over oiled, then check or replace your Reed's, amazingly this is a problem that a lot of people overlook. Then check your carb cleanliness..

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Re: My Baby Won't Start - Please Help

Post by FlyKDXGuy »

6 Riders wrote:You should start at the tank.....is your tank vent plugged? Are you out of gas (or only have reserves left & the petcock is turned the wrong way)Is the petcock working, is the fuel line ok? Pull the Carb drain and see if there is any crud in the bowl and if fuel flows freely with the petcock on. Carb vent lines blocked? Air filter is clean and NOT over oiled, then check or replace your Reed's, amazingly this is a problem that a lot of people overlook. Then check your carb cleanliness..

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That was almost the EXACT order I followed. Spark, petcock, carb, air filter, reeds.

I completely drained the tank and put fresh fuel in it (put just over 1/2 tank in it), the flow out of the peacock was smooth and unrestricted. I also rebuilt the carb (with new jets and gaskets) and it was damn-near spotless when I took it apart, but I cleaned the living hell out of it anyway. Same with all of the vent lines (carb and tank).

Also checked the reeds - no cracks, scratches, or chips. And the air filter was cleaned/oiled as per the instructions that came with it. I even checked the timing and the woodruff key, which were both fine.

I noticed after a fresh swap of transmission oil, I ran the bike for 10 minutes or so and it was cloudy again. So I'm thinking my crank seals went so it's getting too much air rather than not enough fuel. So I bought new crank seals and a complete gasket kit to see if that remedies the issue. They should be here Thursday - so I'll keep everyone posted.

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Re: My Baby Won't Start - Please Help

Post by KDXGarage »

You may want to do a pressure test and vacuum test before disassembly.
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Re: My Baby Won't Start - Please Help

Post by SS109 »

Jason wrote:You may want to do a pressure test and vacuum test before disassembly.
Exactly. Replacing crank seals isn't a small task on a KDX.
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Re: My Baby Won't Start - Please Help

Post by FlyKDXGuy »

SS109 wrote:
Jason wrote:You may want to do a pressure test and vacuum test before disassembly.
Exactly. Replacing crank seals isn't a small task on a KDX.
I dug into the service manual and realized that it is a much bigger job than I expected. I've replaced seals without splitting the cases on my buddy's yz, figured I could do the same with the kdx.

Pressure test it is haha

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Re: My Baby Won't Start - Please Help

Post by FlyKDXGuy »

The compression reading came back a little low, so I decided on replacing the top end.

I put it all back together and it definitely ran better, but it still four-stroked like CRAZY! Come to find out, when I went to AutoZone, the guy didn't give me the exact plug I asked for, he gave a plug deemed "compatible" in his database - which still fit, it just didn't have the Resistor.

I swapped plugs and repacked the silencer and now she runs like a champ!

But hey gents, I super appreciate the help! Happy riding!

-JimImage

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My Baby Won't Start - Please Help

Post by SS109 »

Wow. A stupid improper spark plug. Yeah, never trust most auto parts slingers (I was one for years) when it comes to plug cross references for motorcycles unless they know motorcycles. Stick with NGK BR8ES only and you'll never have a problem. No other brand is even worth looking at.

On that note, glad you got it figured out. Braaaaaap on! :supz:
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