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Discussion Starter · #1 ·
I am having a little trouble getting the carbs on my bike tuned properly, every time I try to adjust the air/fuel screw I end up either too rich or too lean. is there any one who can give me a little advice on making this easier and more exact. are there factory settings I can default to I.E. number of turns for the screw.


Exhaust is stock, air box is stock, filter is clean.

Thanks Guys
 

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i've had great results with 2 1/4 turns out from lightly seated, other members have as well with stock setup, though this can vary bike to bike.

You are CERTAIN your pilot circuits are clear all the way through?

And valve clearances are within spec? (very important)
 

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I read somewhere you want to screw in the pilot screws. Then back them out a half turn. Start the bike and let it idle. Now back out both screws with the bike idling. The idle should get higher and higher then it will start to decrease after a certain point. Set them where the idle is the highest. Then use the idle knob to adjust that.

Whether this works or not, I don't know. As Ducatiman said, everything else has to be in working order. Ducatiman set my carbs at 2.5 turns when he rebuilt them and they were fine. Bike ran beautifully. What are your indicators for rich and lean?
 

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I believe the factory spec is somewhere between 1 & 2 turns out. The FOG mod is designed so that it will lean out the top end, and you're supposed to turn out the pilot screws some to compensate and richen the low end back up (especially since it's pretty lean from the factory). This means that the recommended ~2.5 turns out for the FOG mod should be higher than the stock setting. In stock form, mine seemed to like ~1.25 best (though I didn't spend too much time tuning it, and it didn't stay stock for long).

http://www.ex-500.com/index.php/topic,39813.0.html has a document with some steps for tuning your pilot screws. The doc is originally for a different model carb which has an "air screw" (leaner as you turn it further out) as opposed to our "fuel screw" (richer as you turn it further out), but the process is the same. One of these days I'll get around to wiki-fying that info... It's similar to what Mango said - you turn the idle up a bit to make the changes more noticeable, then just adjust the screws until you get the highest RPMs, which indicates optimum combustion.

I'm not really sure what to tell you other than turn it up if it's too lean, or down if it's too rich. It's not like you're installing jets that only come in certain sizes where you might not be able to get a part that works perfectly - you're adjusting a screw that can be turned a lot or a little to the exact point you need it.
 

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Short of running the bike on a dyno and exhaust analyzer...start at 2 1/4 out (you'll be very close there) and take the bike for a test ride. Open the screws in 1/4 turn increments... your target is best throttle response off the idle circuit while in the leanest possible setting to allow said response.

If you notice "gassy stink" from the pipes, turn in 1/4 increments. Any flat spots or hesitation...somethings wrong.

Again, 2 1/4 to 2 1/2 should land you very close to ideal.

Long term, you'll want to monitor your fuel consumption....you're looking for 45-50 MPG (or better) on a stock EX meanwhile accompanied by acceptable response and performance, no flat or dead spots. It should pull from idle to redline.
 

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Discussion Starter · #6 ·
Thanks Guys for the Help and sorry for taking so long to get back to y'all, the 2 1/4 turns did the trick, I just have to dial it in from here, its got a slight flat spot around 5k RPM, there is no gas smell just exhaust, I cleaned the life outta the carbs then as instructed by a friend used a guitar string to go thru the passages in the carbs, it got gunk out, the carbs I know need a new float needle that's coming really soon. im possibly gonna adjust out about an 1/8th turn. also I have a few exhaust leaks which may be causing issues with flat spots and hesitation.
 

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best to do this in orderly fashion...fix ALL your other issues first, then fine tune, otherwise you'll be wipin' your ass with a hula hoop.
 

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must be good, made millions for the HH company
 

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i just put a dna filter on and the airbox form later years bikes on the engine witch is bigger from the one my bike had before (kle500) and now i have hessitation when i drive . basicaly idles fine . but when i try to accelerate i have problems with fuel. not enough fuel.
 

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ponying on to a 7 year old thread? Suggest opening a new one.
 
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