Kdx220r off idle bog

chriswelfare · Post by **chriswelfare** » 11:30 pm Oct 26 2009

Hi! I have an 03 kdx220r with fmf gnarly pipe, turbine core 2 silencer, and a desnorkled air box. My jetting is 42/130 and my needle is in the second clip from the top. I bought the bike set up this way. I live in Denver and ride between 5 and 10 thousand feet. I have a terrible off idle bog that I cant seem to shake. If i rip the throttle open at low rpms the motor falls flat on its face. If I'm in gear it bogs and then usually picks up again, but if its out of gear idling I can actually kill the motor my twisting the grip quickly. I would accept this as normal and try to adjust my riding style to fit, but I can make the problem vanish by turning on the choke. What is wrong with my bike. I really like this bike and want to keep it so any help or advice you can give would be greatly appreciated!

C-LOC

Post by **fuzzy** » 09:57 am Oct 27 2009

Too lean. pilot mixture can be fine tuned with the air screw on the carb, but must be rough tuned with by changing the actual pilot jet inside. Main jet must be changed from inside as well, but fine adjustments are made at the clip on the slides needle.

chriswelfare · Post by **chriswelfare** » 12:17 am Oct 28 2009

I have tried going up on both the pilot and main circuits. No luck. It does exactly the same thing. I have tried and unchopped air box lid, new spark plug, different needle heights. If I screw the air screw all the way in it seams to fix the bog. What is going on?
Chris

Post by **Indawoods** » 12:35 am Oct 28 2009

It is not getting enough fuel..... makes sense don't it? Raise the needle....

chriswelfare · Post by **chriswelfare** » 08:52 pm Oct 28 2009

It does make sense to me that it is not getting enough fuel. That is why I tried increasing both the pilot and main jet sizes. Because it was suggested, I tried adjusting the needle today. It was set on the second clip from the top. I moved it all the way to the bottom with no change in performance or results. The bog is exactly the same. If I turn the air screw all the way in or put the choke on the bog goes away. I understand that it is running lean, but i don't know how to fix it. So frustrated!
Chris

Post by **Indawoods** » 09:06 pm Oct 28 2009

Your carb needs a good cleaning if nothing is changing... you have a blockage somewhere....

chriswelfare · Post by **chriswelfare** » 09:13 pm Oct 28 2009

What exactly should I clean? I have had both the pilot and main jets out and cleaned them.
Chris

Post by **Indawoods** » 09:15 pm Oct 28 2009

Spray carb cleaner through all the passages and make sure it exits somewhere.... Check the float height, check the needle valve for wear and replace if worn.

Post by **fuzzy** » 10:59 am Oct 29 2009

^ Yep! Also, jsut because you went up one on the pilot doesn't mean that you don't need to go up antoher. Having the air screw in and fixing it indicates this is most likely. Clean carb first though.

Also, check for air leaks by spraying carb cleaner around your intake/etc. If you have one you'll find it.

chriswelfare · Post by **chriswelfare** » 07:42 pm Oct 29 2009

Guys. I've tryed all of these obvious remedies. It's not jetting and it's not needle hight. The carb is clean. Either someone out there has had this problem and has fixed it or it's just the way these bikes are. Could someone go out in the garage and wick the throttle fast on there kdx220r with full pipe and modified air box. I'm pretty sure it's just the way these bikes are.
Chris

Post by **Indawoods** » 08:06 pm Oct 29 2009

If that was a fact... all of our bikes would run like ass.... since we know this isn't the case... well...

chriswelfare · Post by **chriswelfare** » 09:14 pm Oct 29 2009

Thats the thing about it. I think maybe I just ride a little differently. I think most riders never wick the throttle the way i do and so they never experience the bog. I have a crf450x as well and it does exactly the same thing. I took it to a shop and he couldn't make it any better. I have dialed it in now to where I'm fairly happy with it but I was hoping a 2 stroke would be better. I understand how carburetors work and I can't get this one dialed in so I can only assume that this the best this bike can run. Also I recently read an article where the guy had the same problem and couldn't solve it. Thanks for all of the advice, but i think this bike is down the road.
Chris

Post by **Mr. Wibbens** » 09:25 pm Oct 29 2009

chriswelfare wrote:Thanks for all of the advice, but i think this bike is down the road.

Chris

If that's the case maybe someone with a little more patience and ability to tune a bike will get ahold of this bike

Post by **Indawoods** » 09:26 pm Oct 29 2009

If you give... I give. CASE CLOSED.

Post by **Indawoods** » 09:53 pm Oct 29 2009

I know what it is now...

You are not allowing it to warm up before you holeshot!

A KDX takes a good 10-15 minutes to properly warm up before you flog it.

Post by **Julien D** » 10:11 pm Oct 29 2009

My jetting is 42/130 and my needle is in the second clip from the top. I bought the bike set up this way. I live in Denver and ride between 5 and 10 thousand feet

Am I the only one that things a 130 MJ sounds rediculously lean for the thin air @ 5-10k' with the air lid gone and AM pipe and reeds? I know it's a 220, but damn. Was that 130 MJ the jet you "moved up" to??? Wow....

I'm just babbling. You are almost certainly correct in your assessment that it can't possibly be anything as simple as the incredibly lean jetting and overall increased airflow causing a dangerously lean condition. Surely it must be something much more complex and irreversible. It must just be a cursed and evil imitation of an incredibly versatile woods machine. I've seen this before. Things could get dangerous for you if you don't act quickly! If you agree to pay me a small disposal fee of $50 I will come quickly to retrieve, cleanse, and properly dispose of this evil entity that dares to pose as a 2003 KDX

Post by **Mr. Wibbens** » 10:19 pm Oct 29 2009

Indawoods wrote:I know what it is now...

You are not allowing it to warm up before you holeshot!

A KDX takes a good 10-15 minutes to properly warm up before you flog it.

Hmmm, mine only needs about 50 yards

Post by **Indawoods** » 10:21 pm Oct 29 2009

OK.

Post by **fuzzy** » 09:40 am Oct 30 2009

Your 450F needs an accel pump mod. They make aftermarket stuff for that. That's a BIG carb on that air compressor too.

In your thin air you will have more of a problem getting your jetting perfect, or it'll be less tolerant anyway. Richen the jetting up until the bike 4-strokes and then back it off. I'll bet if you get it rich your 'wick' test will pass. I don't mind a tune that's a touch lean on the 'wick test' myself. I can make my bike do it, and I can make it go away

Keep at it.

Post by **Mr. Wibbens** » 11:47 am Oct 30 2009

Indawoods wrote: OK.

Sure is hell don't need 10 - 15 minutes

All I need is about 50 yds before mine will clean up and hit the powerband

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Kdx220r off idle bog

Kdx220r off idle bog