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Discussion Starter · #1 ·
I have a 2007 ninja 500. My bike has recently started bogging ( i suppose ) around 2-4k rpms and then when it passed 4500 rpms it’ll rip like it is usually does. I cleaned the carbs throughly and put a new k&n air filter in it. I’ve found a way to manipulate it though. When i adjusted the throttle control knob so it idles around 3k if i rev it past 6k rpms BUT if i just rev it a little to like 3500-4000 rpms it will drop down and idle at around 1k rpms. Anyone got a solution for me?
 

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Fast Old Guy
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Do the "FOG MOD" and adjust the pile screws as per the instruction there

FOG
 

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Discussion Starter · #3 ·
Do the "FOG MOD" and adjust the pile screws as per the instruction there

FOG
My bike was working fine a while back though. I want to get it running correctly before adding a mod to it. I see some people on the forum have problems regarding the mod once they install it id rather fix the problem at hand the correct way.
 

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Twist that black idle SPEED knob to about 1100-1200 RPMs and leave it there. Messing with too many things simultaneously will add up to confusion.
You need the opening of the airbox, as FOG mentioned. But low RPMs may be some bad gas, or your pilot screws (bottom front of each carb) might be off. You removed the steel plugs covering the pilot screws, correct?
 

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My bike was working fine a while back though. I want to get it running correctly before adding a mod to it. I see some people on the forum have problems regarding the mod once they install it id rather fix the problem at hand the correct way.
if a bike bogs down at low revs it's nearly always down to a weak mixture. try revving the engine from a very cold start without the choke. it bogs down. this is because it's trying to run on too weak a mixture. it does this because the engine is cold and being cold the combustion temperature is too low to burn the amount of fuel present in the mixture coming from the jets. the choke (enricher) feeds more fuel into the engine to make it run richer. so the engine revs increase.

when a weak mixture occurs and causes bogging it will be down to either not enough fuel in the mixture or too much air.
several things can cause this from low fuel levels in the float bowls. to blocked or partially blocked pilot jets or pathways.
incorrectly set mixture screws, or an air leak some where after the butterflies. the idle screw should be set at a rev range of 1100/1200 rpm. if you do this when the engine is cold you have to alter it after the engine has warmed up or it will idle too fast. conversely when it is set warm the idle will be less when the engine is cold. because of the reason stated above.
in summary. if your bike bogs at 2k, the pilot jets/pathways are blocked or partially blocked. the float levels are too low,
the mixture screws are incorrectly set. or you have a vacuum leak somewhere on the carburettor pipe work.
 

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Did you remove/clean/replace both needle jets? Those are small stainless jets held in place by the main jets. The slide needles pass through them. Sometimes they fall out unnoticed.
 

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my view is the carbs have not been cleaned/adjusted well enough, it happens so many times people having to do them 3 or 4 times doing a deeper clean before they find and cure the underlying issues.
people forget that carbs are a precision instruments that have to deliver exactly the right amount of fuel/air to the engine in all conditions from idle to full throttle.
they require a complete strip down, inspection, thorough clean. reassembly with new consumables. and final adjustment. or there just not clean. a quick strip spray with carb cleaner. and wipe down is not a carburettor overhaul.
we have all seen a set of @ducatiman's carbs. the level of work, dedication, and expertise that goes into them. if your not giving the same attention to detail as that, your not cleaning the carbs properly.
carburettors have to be done properly or your never sure they are not the source of problems that could well be somewhere else.
I once had a problem dialling in the carb adjustments never quite right, always off a little. if I had not been 100% sure the carbs were done properly I would not have looked somewhere else. I found a very small split in the underside of one of the rubber boots that was letting air in causing the issue.
 

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but but but i've read a million times on the internet....carbs are easy. Right, sure they are.
 
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but but but i've read a million times on the internet....carbs are easy. Right, sure they are.
they are providing you know what your doing and why your doing it, most do not.
I must have watched a dozen carb cleaning videos on the net. and seem to find myself writing in the comments, why did you miss this step, why did you not do the other, why are you trying to instruct others when you clearly are not doing them properly. never get any response of course. but the comments are there for others to read and understand.

personally I have no idea why the EX seems to have so many carb issues when most brands and models do not. it cannot be the carbs as they are used on other bikes without issues.
some run for years without the carbs being touched or giving problems. somehow the EX is different as soon as there is a running problem it has to be the carbs.
 
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they are providing you know what your doing and why your doing it, most do not.
I must have watched a dozen carb cleaning videos on the net. and seem to find myself writing in the comments, why did you miss this step, why did you not do the other, why are you trying to instruct others when you clearly are not doing them properly. never get any response of course. but the comments are there for others to read and understand.

personally I have no idea why the EX seems to have so many carb issues when most brands and models do not. it cannot be the carbs as they are used on other bikes without issues.
some run for years without the carbs being touched or giving problems. somehow the EX is different as soon as there is a running problem it has to be the carbs.
There are so many variables at stake it would make you dizzy. Co-worker bought a chain saw, he had to get a new carburetor for it in a year or so, mine I have not touched mine and it is from 06. Gas, use, the way the item is stored, temperature its stored, how its used - its endless. My lawnmower I have not touched the carburetor since new, it must be close to 20 years old, my generator bought in 06 needed a carburetor service which just required a fast cleaning to run tip top again.

I had two issues with two bikes in the past that was weird. I had a job where I parked my EX and one of my VFRs in an air conditioned enviornment all day. My EX developed a leak on one of the bowls, it might have been a stuck float, I ended up getting some bowl gaskets and just went through it, problem corrected. My Vfr, developed a leaking o-ring on one of the fuel tubes which fouled out one cylinder. I changed the fuel rails/o-rings and changed oil cause of the contamination and all has been well, over 3 years ago.

The way I role with these bikes is I always use a bike cover when I commute on them. They sit either in the open or under a shelter (with-out cover) all day in sub tropical climate (South Florida) and never had problem like this in the past.
 

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Discussion Starter · #11 ·
Twist that black idle SPEED knob to about 1100-1200 RPMs and leave it there. Messing with too many things simultaneously will add up to confusion.
You need the opening of the airbox, as FOG mentioned. But low RPMs may be some bad gas, or your pilot screws (bottom front of each carb) might be off. You removed the steel plugs covering the pilot screws, correct?
Wasn’t really messing with a bunch of things. Just that knob trying to find the sweet spot for idle rpms. If i rev it under 4k rpms it will drop to about 1k rpms but if i rev it to 6k+ rpms it will stay at around 3k rpms
 

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Wasn’t really messing with a bunch of things. Just that knob trying to find the sweet spot for idle rpms. If i rev it under 4k rpms it will drop to about 1k rpms but if i rev it to 6k+ rpms it will stay at around 3k rpms
in that case something is amiss. sticking or poor adjustment. perhaps a kink in the cable a stiff joint or the slides sticking.
poor adjustment of the (push) cable would do that.
you could try manually pushing the throttle closed at the cable ends with long screwdriver when it idling at 3k see if the revs drop down to normal.
 

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Clean carbs are vital of course...but Just casting a wider net , I'd consider the fuel supply as a potential problem too. dirt in filters, and even the vacuum operating the petcock-ie: "goosing "the bike may give temporary relief as the increased manifold vacuum pulls the petcocks plunger....so giving the bike unrestricted fuel from a temporary tank.....stuff like that.
ADDED: you didn't mention "lack of power" when it's "bogging" That'd be an important symptom...aka "lean" or "rich" or even an ignition- timing problem. And stuff like yorkie has per the cable is not going to be found easily in the manual ...it's good to cross the easy-to-test ideas off the list !

I think you are right to stay "stock" until you know what the trouble is . Start with the manual's specs. Workarounds are useful as "troubleshooting" info. but a baseline is really important.
 

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Fast Old Guy
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Stock sucks, the biggest problem with the Ex carbs is the stock settings. To get past the emission refs, they set up the carbs overly lean, then compensated by too rich a setting over 5000 RPM. You bottom end problems are because your engine is not perfect any more. therefore you need to adjust the settings.
I told you how in the FOGMOD post. Choosing not to take advantage ,is just shooting yourself in the foot
 
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Moderating: Fair & Just
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I hear what you're sayin' fog...but.....
The OP is not at stock, he's at sub-stock.
Correct me if I'm wrong, but I believe the FOGMOD is designed to take what is stock and improve upon it. It's not designed to fix something that has gone wrong with stock.

Wouldn't it make more sense to first fix the issue that has decreased the performance he has become accustomed to. And then move on to the FOGMOD to gain extra performance?
 

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Fast Old Guy
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well he put a KN filter in place further aggravating his slightly lean fuel mixture .he must open the pilot screws and adjust them according to current conditions IE: FILter,carb conditions . He will never get it to respond down low until he does.

FOG
 

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well he put a KN filter in place further aggravating his slightly lean fuel mixture .he must open the pilot screws and adjust them according to current conditions IE: FILter,carb conditions . He will never get it to respond down low until he does.

FOG
Good point.
 

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You removed the steel plugs covering the pilot screws, correct?
An answer to this OP? I'll submit if you "cleaned" your carbs while leaving pilot screws intact......your carbs are not truly cleaned.

Furthermore, during your cleaning efforts, did you check fuel levels via clear tube method, adjusting as needed?
 
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Discussion Starter · #20 ·
An answer to this OP? I'll submit if you "cleaned" your carbs while leaving pilot screws intact......your carbs are not truly cleaned.

Furthermore, during your cleaning efforts, did you check fuel levels via clear tube method, adjusting as needed?
I have non adjustable floats and yes i removed the pilot screws
 
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