No Idle After Rebuild

[CarsonMcI]

This is the second top end rebuild I’ve done on my 98 KDX200. This time I got v force reeds for it and I put in a CEL needle as the stock one had a chip in it and I decided it was time to replace it. The bike started up fine but it wouldn’t idle high enough. I even turned the plastic idle adjustment screw all the way in and it’s only enough to keep it idling for around 3 seconds before it dies out. It idles fine of course if I give it 1/16 of throttle to keep it from dying. Any ideas? It has the stock 160 main jet and 48 pilot.

[Molly's 70]

That sound super rich to me. Never seen a plastic idle adjustment screw, only brass. Check for air leaks.

[SS109]

That pilot jet is huge. I run a 38pj at 2000ft.

[Slick_Nick]

That sound super rich to me. Never seen a plastic idle adjustment screw, only brass. Check for air leaks.

He’s talking about the throttle stop screw.

[John_S]

When I installed the V force reeds I couldn’t get it to idle (overly rich) and called customer support They told me it’s not uncommon to need to go down 1-2 pilot jet sizes with their reeds. I dropped one size plus another 1/4 or so leaner on the air screw and it was idling good.

[CarsonMcI]

When I installed the V force reeds I couldn’t get it to idle (overly rich) and called customer support They told me it’s not uncommon to need to go down 1-2 pilot jet sizes with their reeds. I dropped one size plus another 1/4 or so leaner on the air screw and it was idling good.

I went to a 38pj and it idled but only at 3 1/2 turns out on the mixture screw with the plastic idle screw still all the way in. Smoking a lot also and not able to rev all the way out

[SS109]

You're running on the main jet if you have the idle speed screw turned in that far so the pilot jet isn't really doing squat. Have you checked your jet block gasket in the carb? That's what I'm leaning towards as being the issue due to the idle screw position yet on a tiny 38pj and 3.5 turns out on the idle mix screw trying to lean it out. That or a bad float and/or needle valve

[CarsonMcI]

You're running on the main jet if you have the idle speed screw turned in that far so the pilot jet isn't really doing squat. Have you checked your jet block gasket in the carb? That's what I'm leaning towards as being the issue due to the idle screw position yet on a tiny 38pj and 3.5 turns out on the idle mix screw trying to lean it out. That or a bad float and/or needle valve

So I believe you’re correct about the jet block gasket. Threw in a cheap Chinese carb from Amazon and it ran awesome and hardly smoked. So I suppose the gasket on the oem carb went bad and was letting in more fuel than it should. Thank you!

[KDXGarage]

I am glad you got somewhere on it. This reaffirms my belief in having spare parts to test with!