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Old 06-16-2009, 09:55 PM   #13 (permalink)
Master EcoModder
Join Date: May 2009
Location: New Jersey
Posts: 389

2003 Ninja EX250 - '03 Kawasaki Ninja EX250
90 day: 78.57 mpg (US)

Saturn - '99 Saturn SL1 Base
90 day: 47.27 mpg (US)
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Originally Posted by beatr911 View Post
OOPS! Should've read the original post. Guess you did the gearing.

Well I still think you can reach 100 mpg. I picked up 5+ mpg on my Connie by lowering the fuel level in the float bowls about 10mm, effectively leaning all circuits. This may have other adverse affects on the main, but I almost never dip into the main circuits.

To do it better weld in a bung on the exhaust and install a cheap O2 sensor and monitor the voltage with an AFR gauge or a voltmeter. Adjust jetting, air orifices and mixture screws accordingly after doing good research on how your carbies work. This will get you pretty darn close and you won't spend $400 on a wide band set up.

Additionally, I'm considering using intake air heat to seasonally fine tune the carbs though I don't know how effective it will be with the CV carbs we have.
I think its possible for me to reach 100mpg too... i am very close

My carbs are much smaller. The stock float bowl height in my carbs is 17mm, and when i took the carbs out a few months ago to clean them, they were both exactly at 17mm. I dont think i'll be able to decrease it nearly as much as you did. I may only be able to go 3-5mm.

I dont think i ever use the main jets on my bike. In fact, most of my riding probably is influenced by the pilot jet and screw. Even on the highway, i dont think i go more than half throttle, even with the changed gearing.

Are you suggesting using a narrow band or wide band sensor? I have a few narrow band sensors laying around from various cars i have owned. The only wideband i have is in my 1984 Buick Grand National, and its a part of the FAST standalone ecu that i have in the car. All a narrow band + voltmeter will tell me though is whether or not my current mixture is stoichiometric. I can see your pint. The only problem is that the exhaust pipes on the ninja 250 are only 3/4" ID each (i just measured), so i would need to find a NB sensor small enough to fit.

Another thing is that in stock configuration, the Carbs on this bike are a hassle to work on.... because of the huge factory air box. If i were to replace the airbox with pods, it would make things much easier.
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My 101.5 MPG 2003 Kawasaki Ninja 250

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