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Old May 30th, 2023, 01:22 PM   #25
dan151
ninjette.org member
 
Name: Dan
Location: USA
Join Date: May 2023

Motorcycle(s): 2012 Kawasaki Ninja 250R

Posts: 20
Quote:
Originally Posted by ducatiman View Post
How, unless you measured, could you be absolutely sure of this?
Also suggest all brand new "consumables" (orings, float valves) and a full treatment to the float valve seats, followed by setting fuel levels based upon actual wet testing using a gravity fed fuel source, letting them set for 60 minutes to assure floats are fully sealing.

Best o' luck.
Quote:
Originally Posted by Bob KellyIII View Post
Personally I think you shouldn't be confident that the carbs are clean. the carbs on these bikes are the hardest to clean that I have ever seen "THEY DO NOT COME CLEAN EASILY"
I am a retired Motorcycle mechanic but getting old at 70 yrs now, and I know bike carbs.
yet it took me 3 trys to get the carbs clean !!!! I used the time tested methods , not an ultrasonic cleaner, ( which I now have by the way) but after riding the bike all season I could tell the carbs were not as clean as I thought they were.
over the winter I did a valve adjustment and sent the carbs to Gordon (Ducattiman)
because I didn't want to fight these silly carbs again.... he cleaned them for me and this same problem cropped up He graciously offered to check them out again for me so I sent them back to him... he did a re clean and after discussing it we decided to put in smaller main jets and 2 shims under the needles.... and after much tinkering I think she is running alot better now.... I still haven't ridden it on the street but I think it is finally
back up and running right.
....
with all the smog garbage on these things and the settings so very fine to get them to pass smog they run on a razors edge.....any thing will screw up the running of these bikes, but once you get them tuned in they run fantastically and will stay that way for ages... My bike does not get alot of use it sets most of the time. it's only got 5600 miles on it and is in like new condition.... yet this same problem cropped up as what happened to you. you'll notice in the manual that each carb is slightly different right from left..... they have different jet needles and the mixture screws are set differently from each other.... this to me is very strange to see ! it is a highly tuned powerhouse
of a bike that develops alot more power than the average 250cc bike so any speck of dirt in the carbs can effect it's running. ( I put an in line fuel filter on my bike first thing. )
.....
I sujest pulling off the carbs and paying close attention to the passageways inside the carbs in cleaning them again....the pic. below helped me a bunch those passageways do not come clean easily.... and you can't poke a small spring wire through them yet they must be super clean.
....
Bob
As suggested, I'm going to try another carburetor cleaning, fluid fuel level check, and step down a size in the pilot and main jet. The stock Keihin CVK30 carbs on this bike have a #38 pilot and #98 main jet. Looks like the next step down would be a #35 pilot and #95 main. Could anyone confirm if these are the correct jet series? I am referencing the attached chart from Keihin.

Main Jet Series: 99101-393
Pilot/Slow Jet: N424-25B

https://www.keihin-na.com/assets/1/7/jetlist.pdf
Attached Images
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