2006 KXF450 bogging

Finally getting on the bike this year, and notice I have less power in 2nd from idle. If I recall last year, I could go from a stop in 2nd and have power at all spots on the throttle. This year, when in 2nd and at a stop, I crack the throttle and it bogs a little before it gets going.

Any ideas? Never touched the jetting, only difference is regular gas, not "advance" premium I usually use, but doubt that would do it.

Finally getting on the bike this year, and notice I have less power in 2nd from idle. If I recall last year, I could go from a stop in 2nd and have power at all spots on the throttle. This year, when in 2nd and at a stop, I crack the throttle and it bogs a little before it gets going.

Any ideas? Never touched the jetting, only difference is regular gas, not "advance" premium I usually use, but doubt that would do it.

Gotta use premium.

When was the last time you changed the gas? Is it old?

Accelerator pump diaphram might be old and need of replacement.

I'll drain the gas and fill with premium, re-adjust fuel screw and test. I'll go from there

Drained the gas, put in premium. Ran the bike for a 10 minute run. Still bogging in 2nd, from near stop to WOT without clutch. Fuel screw is 3.25 turns in, but that is a little strong. I'll put it to 2 tomorrow and test. Looks like I can check the accelerator pump without removing the carb. What should I be looking for in there?

Drained the gas, put in premium. Ran the bike for a 10 minute run. Still bogging in 2nd, from near stop to WOT without clutch. Fuel screw is 3.25 turns in, but that is a little strong. I'll put it to 2 tomorrow and test. Looks like I can check the accelerator pump without removing the carb. What should I be looking for in there?

Fuel screw needs to be within 1-2.5 turns out, no more. If you need more, your pilot jet is clogged or too small.

Follow the fuel screw adjustment procedure:

http://www.thumpertalk.com/forum/showthread.php?t=327405

If you get bog rolling on the throttle, it's fuel starvation to the float bowl.

If you get bog when the throttle is 'whacked' under load, the issue is fuel starvation of the Accelerator pump, or a clogged pump nozzle (or broken linkage parts, which is unlikely).

Tilt up the subframe so you can see inside the carb. With the motor off, gas on, using a flashlight, look to see if a stream of gas shoots down the carb throat when you whack the throttle. It should do it every time, no matter how many times or how fast you whack it. It should not hit the slide, ever.

It should appear to shoot 6 ft into the motor.

http://www.youtube.com/watch?v=mSZAfjRcWFU

If it dribbles out of the nozzle, it's most likely clogged at the nozzle, or the apump diaphragm is torn. Remove apump cover and inspect.

You should have a 50 or smaller leakjet to get good results.

Bigger makes it too short of a squirt, smaller makes it too long.

The apump linkage can be fine tuned for better results, but should be close enough from the factory to be ride-able, unless someone has been playing with the carb.

If it is clogged, you need to remove the carb and clean with compressed air and brake cleaner.

Fuel screw needs to be within 1-2.5 turns out, no more. If you need more, your pilot jet is clogged or too small.

Follow the fuel screw adjustment procedure:

http://www.thumpertalk.com/forum/showthread.php?t=327405

If you get bog rolling on the throttle, it's fuel starvation to the float bowl.

If you get bog when the throttle is 'whacked' under load, the issue is fuel starvation of the Accelerator pump, or a clogged pump nozzle (or broken linkage parts, which is unlikely).

Tilt up the subframe so you can see inside the carb. With the motor off, gas on, using a flashlight, look to see if a stream of gas shoots down the carb throat when you whack the throttle. It should do it every time, no matter how many times or how fast you whack it. It should not hit the slide, ever.

It should appear to shoot 6 ft into the motor.

http://www.youtube.com/watch?v=mSZAfjRcWFU

If it dribbles out of the nozzle, it's most likely clogged at the nozzle, or the apump diaphragm is torn. Remove apump cover and inspect.

You should have a 50 or smaller leakjet to get good results.

Bigger makes it too short of a squirt, smaller makes it too long.

The apump linkage can be fine tuned for better results, but should be close enough from the factory to be ride-able, unless someone has been playing with the carb.

If it is clogged, you need to remove the carb and clean with compressed air and brake cleaner.

I called a local mechanic, and he said these bikes arent meant to be hammered on in 2nd from a near stop. They need to be rolled on. Is this true? Either way, I have the carb off the bike and will investigate things. Video quality is rough, and sorry for showing my mean mug. But here is the stream http://youtu.be/0OJ3YkYpU2o?hd=1

Goes strong for about 3/4 inches and dies. Not 6ft. I'll hook the throttle back up and do it like that video and see how strong the stream is. Seems weak though. Does the fuel screw have anything to do with this stream? The local guy said as long as you get some squirt..... Doesn't seem right, when that video is shooting like 6 ft. Also, what is the AP mod I keep reading about, but can't find any info on?

Edited by Themitch

I called a local mechanic, and he said these bikes arent meant to be hammered on in 2nd from a near stop. They need to be rolled on. Is this true?

NO, HE IS CLUELESS. THE BIKE SHOULD LAUNCH OR SPIN THE TIRE EVERY TIME YOU WHACK IT, UNLESS YOU ARE IN TOO HIGH A GEAR.

Either way, I have the carb off the bike and will investigate things. Video quality is rough, and sorry for showing my mean mug. But here is the stream http://youtu.be/0OJ3YkYpU2o?hd=1

Goes strong for about 3/4 inches and dies. Not 6ft. I'll hook the throttle back up and do it like that video and see how strong the stream is. Seems weak though.

YES THAT IS VERY WEAK. YOU HAVE A PUMP ISSUE AND A TIMING ISSUE (IT APPEARS TO BE HITTING THE SLIDE).

Does the fuel screw have anything to do with this stream?

NO, THE FUEL SCREW IS A PILOT/IDLE CIRCUIT ADJUSTMENT ONLY

The local guy said as long as you get some squirt..... STOP LISTENING TO THIS GUY CAUSE HE'S A BONE HEAD.

Doesn't seem right, when that video is shooting like 6 ft.

WHAT YOU NEED TO DO:

1. REMOVE APUMP COVER

2. INSTALL AN APUMP RE-BUILD KIT. DONT FORGET THE TINY ORINGS

3. REPLACE THE LEAK JET WITH A 50 (PROBABLY A 70 NOW)

4. RE-INSTALL APUMP AND FLOAT BOWL

5. ADJUST A PUMP LINKAGE SCREW SO IT JUST TOUCHES THE THROTTLE LINKAGE, THEN BACK IT OFF 1/2 TURN

Also, what is the AP mod I keep reading about, but can't find any info on?

IF YOUR CARB HAS A 'BLUE' APUMP LINKAGE ARM, IT'S ALREADY DONE AT THE FACTORY. IF IT DOESN'T, YOU CAN CAN ADD AN ORING TO STIFFEN THE APUMP DETENT SPRING. BETTER YET IF YOU REPLACE THE DETENT SPRING WITH A MERGE RACING SPRING. DO A YOUTUBE SEARCH ON 'FCR MX ORING' TO SEE WHERE TO INSTALL ORING.

Thanks for the info, i'll get on it. What do you mean a timing issue? I assume you mean something other than the cam chain timing right? Because I set that when I shimmed the valves.

No, he is talking about the AP timing. You should first check/set it according to the manual to ensure it is correct before you try to fine adjust it.

Also, you should never, ever be in 2nd gear at a near stop. At idle, under load like that can be very detrimental to the engine, major piston slap can occur, possibly even bend a rod or shatter a barrel.

And your local mechanic is utterly clueless, Avoid him.

my 07 will ROAST the rear tire in 2nd gear off-idle..

No, he is talking about the AP timing. You should first check/set it according to the manual to ensure it is correct before you try to fine adjust it.

Also, you should never, ever be in 2nd gear at a near stop. At idle, under load like that can be very detrimental to the engine, major piston slap can occur, possibly even bend a rod or shatter a barrel.

And your local mechanic is utterly clueless, Avoid him.

It's not that I want too do it all the time. Its that I noticed the problem that way at a tight back yard track. Sort of like I know the bike should, but won't sort of deal. I got the shop manual, and will be taking apart the carb tommorow/tuesday night. I'll post findings.

I can't find any AP rebuild kits or leak jets online. Any help?

It's not that I want too do it all the time. Its that I noticed the problem that way at a tight back yard track. Sort of like I know the bike should, but won't sort of deal. I got the shop manual, and will be taking apart the carb tommorow/tuesday night. I'll post findings.

I can't find any AP rebuild kits or leak jets online. Any help?

http://www.dirtrider.com/tech/141_0707_keihin_fcr_carb_rebuild/index.html

It's called google

http://www.pjmotorsports.com/power-pumps-covers.html

When everything is working properly, your 06 carb is near idiot proof to throttle use/abuse. They are amazing. Not that this is a good habit ... but you should be able to wide open to closed "chop" the throttle 3 times in one tight rut and the engine responds hard every time. You probably already experienced that. If so then over time something in your carb is worn, sticking or blocked. Problems with steady throttle use = jetting issues. Problems with quick throttle opening (only) = AP issues. You could go to somewhere like motosport.com and buy all the AP parts you want, then the AP just needs adjustment. Kawi put a 70 AP leak jet in the carb to make expert riders happy who ride higher in the revs (less excess fuel so more power). But for many or most guys a smaller leak is the go.

Here is how I adjusted my AP screw http://www.thumpertalk.com/forum/showpost.php?p=10062175&postcount=6

The carb should work great bone stock correct? Reason i'm asking, is I can get a used carb in great shape for near the price of the jet kits/diaphram. But not a good purchase if the bike has issues from stock. Let me know, thanks.

The carb should work great bone stock correct? Reason i'm asking, is I can get a used carb in great shape for near the price of the jet kits/diaphram. But not a good purchase if the bike has issues from stock. Let me know, thanks.

Never buy a used carb unless you know the bike and person it came from.

It takes very little to destroy a carb.

And no, you have to do the same work on any stock carb.

While taking the carb apart, I see it says "flat CR" on a cover near the top. Is that even the correct carb for this bike? The manual says KEIHIN FCR40, is this the same thing, or am I working with the wrong carb.

While taking the carb apart, I see it says "flat CR" on a cover near the top. Is that even the correct carb for this bike? The manual says KEIHIN FCR40, is this the same thing, or am I working with the wrong carb.

That is correct.

It also say fcr somewhere on it.

It should have a little removable 'window' on the top.

Not every country gets the exact same (looking) carb.

http://www.bikebandit.com/houseofmotorcycles/2006-kawasaki-kx-450f/o/m3769#sch436146

Here we are. I took the carb partially apart and here is what I found.

The diaphragm appears to be in decent shape and clean. Cleaned the area with compressed air and cleaning solvent. Put back together. Removed throttle cable cap, cleaned and adjusted the AP screw in all the way, and back 1 turn. Not sure if that is what krannie meant, but the manual says to do that and check for slack in the rod. I'll have to re-check that.

Took the bowl off, and noticed i'm missing the two screws that hold it on, on the AP plunger side. This could be causing an issue when the plunger pushes in. No dirt got in the bowl, but hopefully this was an issue.

See video for my progress so far. Also, the green paint/blue paint i'm referring to in the video. Does that mean the "ap mod" was done at the factory?

http://youtu.be/-MK0Xy9plnc?hd=1

Anyone know off the top of their head the thread count and size of the screws holding the float bowl on?

Edited by Themitch

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