edit- 08Sep08. In order to keep this data base a source of easy to find info, I ask that only information from the cut and paste portion be included. If you have any questions or comments for people, please post them in the jetting database discussion thread here.... http://www.kawiforums.com/showthread.php?t=119320
Edit 31-July-2011: If you post comments or questions in this thread instead of the above listed thread instead of just your jetting information you will refer an infraction. You really need to read threads before aimlessly commenting in them. --VeX
There has been a lot of information on rejetting the 250R in this forum. The problem is, the bits and pieces of information is scattered not only in separate threads among the forum, but in separate posts in threads that sometimes have nothing to do with jetting in the thread title. The purpose of this thread is to consolidate the information from people who have done any type of work to their carburetor jetting to improve the stock bike's rideability. Your contributions is what will make this an valuable tool for anyone looking to rejet their bike in the future.
Are you nuts!!??? Why would anyone want to even consider rejetting their perfectly good, brand new bike?
The stock 250R is marketed as a high mileage, economy bike and as such, the factory has seen to jet the bike as lean as possible to eek out the very best MPG numbers and to also adhere to emissions laws in the US. Kawasaki has done a very good job in selecting the best combination of jetting components to make the 250R a very miserly, gas sipping vehicle. It is ironic, however, that the very jetting which makes the bike a gas sipper, makes it a very unfriendly beginner bike as far as throttle control and rideability. Add to that, poor quality control at setting the mixture screws properly from the factory and you end up with a bike that is difficult to start, takes a long time to warm up and even when warm is difficult to get moving from a stop without revving it to about 4-5k just to get moving smoothly. Add to that the sometimes unexpected hiccup when the bike is just starting to get moving and you end up with a lot of dropped bikes from beginners. Instead of being rider friendly, it makes riding the bike lot more difficult than it needs to be. Rejetting your bike will address this low speed glitch. If you would like more info on jetting, this is a very good primer… http://faq.ninja250.org/wiki/I_want_to_improve_my_carburetor_jetting
Any other benefits?
Glad you asked!! With rejetting, it is possible to extract more power out of the little 250 motor. The factory tuned it for mileage… you can tinker with the jetting to extract more power, though be advised gas mileage will be affected. What I like is that rejetting increases the amount of power available in the lower rpms ranges and in doing so makes the bike much easier to ride and much more rider friendly… two things that greatly benefit someone new to riding a motorcycle.
So, on to the purpose of this thread... In brief, please cut and paste the following as I have in post #2 and help start building a database in the 250R forum. As much as possible, please stay on topic (yeah, right!!) so the information will be easily accessible by those searching for jetting help in the future. You are more than welcome to come back and post new jetting specs in the future in another post if you should redo your jetting. Please comment on any improvements rejetting did for you if you do repost.
As a baseline, these are the stock 2008 jetting specs-
From the service manual-
Make, Type- Keihin, CVK30
Main Jet- #98
Optional mains- #92,95,100,102
Main Air Jet- #100
Jet Needle- left-N9VU right-N9VW
Needle Jet- #6
Pilot Jet- #38
Pilot Air Jet- #100
Starter Jet- #48
Pilot Screws (turns out)- left- (2 1/2) right- (1 3/4)
Throttle Valve- 11degrees 00seconds
Idle Speed- 1300 +/- 50 rpm
Carb Sync Vacuum- less than 2.7 kPa (2 cmHg) difference between two carburetors.
Service Fuel Level- 0.5 +/-1mm (0.02 +/-0.04 in.) above the mating surface of the carburetor float bowl.
Float Height- 17 +/-2mm (0.67 +/-0.08 in.)
---------------------------------------------------------------------------------------
Here are some main jet conversions between manufactures-
Width------Keihin # -- DynoJet # --- Mikuni #
0.0350---- 92.5--------- 92----------- 86.3
0.0360---- 95----------- 94----------- 88.1
0.0370---- 97.5--------- 96----------- 90.0
0.0380---- 100---------- 98----------- 91.9
0.0390---- 102.5------- 100---------- 93.8
0.0400---- 105--------- 102---------- 95.6
0.0410---- 107.5------- 104---------- 97.5
0.0420---- 110--------- 106---------- 99.4
0.0430---- 112.5------- 108--------- 101.3
0.0440---- 115--------- 110--------- 103.1
0.0450---- 117.5------- 112--------- 105.0
0.0460---- 120--------- 114--------- 106.9
0.0470---- 122.5------- 116--------- 108.8
0.0480---- 125--------- 118--------- 110.6
0.0490---- 127.5------- 120--------- 112.5
0.0500---- 130--------- 122--------- 114.4
Mahalo to all that contribute.
-----------------------------------------------------------------------------------------------------------------
YEAR:
INTAKE MODIFICATIONS:
EXHAUST MODIFICATIONS:
JET KIT OR STOCK?
BRAND OF JET KIT?
MAIN JET:
NEEDLE AND CLIP POSITION:
MIXTURE SCREW SETTINGS:
ELEVATION:
MISCELLANEOUS INFORMATION ABOUT YOUR BIKE’S JETTING SETUP:
.
Edit 31-July-2011: If you post comments or questions in this thread instead of the above listed thread instead of just your jetting information you will refer an infraction. You really need to read threads before aimlessly commenting in them. --VeX
There has been a lot of information on rejetting the 250R in this forum. The problem is, the bits and pieces of information is scattered not only in separate threads among the forum, but in separate posts in threads that sometimes have nothing to do with jetting in the thread title. The purpose of this thread is to consolidate the information from people who have done any type of work to their carburetor jetting to improve the stock bike's rideability. Your contributions is what will make this an valuable tool for anyone looking to rejet their bike in the future.
Are you nuts!!??? Why would anyone want to even consider rejetting their perfectly good, brand new bike?
The stock 250R is marketed as a high mileage, economy bike and as such, the factory has seen to jet the bike as lean as possible to eek out the very best MPG numbers and to also adhere to emissions laws in the US. Kawasaki has done a very good job in selecting the best combination of jetting components to make the 250R a very miserly, gas sipping vehicle. It is ironic, however, that the very jetting which makes the bike a gas sipper, makes it a very unfriendly beginner bike as far as throttle control and rideability. Add to that, poor quality control at setting the mixture screws properly from the factory and you end up with a bike that is difficult to start, takes a long time to warm up and even when warm is difficult to get moving from a stop without revving it to about 4-5k just to get moving smoothly. Add to that the sometimes unexpected hiccup when the bike is just starting to get moving and you end up with a lot of dropped bikes from beginners. Instead of being rider friendly, it makes riding the bike lot more difficult than it needs to be. Rejetting your bike will address this low speed glitch. If you would like more info on jetting, this is a very good primer… http://faq.ninja250.org/wiki/I_want_to_improve_my_carburetor_jetting
Any other benefits?
Glad you asked!! With rejetting, it is possible to extract more power out of the little 250 motor. The factory tuned it for mileage… you can tinker with the jetting to extract more power, though be advised gas mileage will be affected. What I like is that rejetting increases the amount of power available in the lower rpms ranges and in doing so makes the bike much easier to ride and much more rider friendly… two things that greatly benefit someone new to riding a motorcycle.
So, on to the purpose of this thread... In brief, please cut and paste the following as I have in post #2 and help start building a database in the 250R forum. As much as possible, please stay on topic (yeah, right!!) so the information will be easily accessible by those searching for jetting help in the future. You are more than welcome to come back and post new jetting specs in the future in another post if you should redo your jetting. Please comment on any improvements rejetting did for you if you do repost.
As a baseline, these are the stock 2008 jetting specs-
From the service manual-
Make, Type- Keihin, CVK30
Main Jet- #98
Optional mains- #92,95,100,102
Main Air Jet- #100
Jet Needle- left-N9VU right-N9VW
Needle Jet- #6
Pilot Jet- #38
Pilot Air Jet- #100
Starter Jet- #48
Pilot Screws (turns out)- left- (2 1/2) right- (1 3/4)
Throttle Valve- 11degrees 00seconds
Idle Speed- 1300 +/- 50 rpm
Carb Sync Vacuum- less than 2.7 kPa (2 cmHg) difference between two carburetors.
Service Fuel Level- 0.5 +/-1mm (0.02 +/-0.04 in.) above the mating surface of the carburetor float bowl.
Float Height- 17 +/-2mm (0.67 +/-0.08 in.)
---------------------------------------------------------------------------------------
Here are some main jet conversions between manufactures-
Width------Keihin # -- DynoJet # --- Mikuni #
0.0350---- 92.5--------- 92----------- 86.3
0.0360---- 95----------- 94----------- 88.1
0.0370---- 97.5--------- 96----------- 90.0
0.0380---- 100---------- 98----------- 91.9
0.0390---- 102.5------- 100---------- 93.8
0.0400---- 105--------- 102---------- 95.6
0.0410---- 107.5------- 104---------- 97.5
0.0420---- 110--------- 106---------- 99.4
0.0430---- 112.5------- 108--------- 101.3
0.0440---- 115--------- 110--------- 103.1
0.0450---- 117.5------- 112--------- 105.0
0.0460---- 120--------- 114--------- 106.9
0.0470---- 122.5------- 116--------- 108.8
0.0480---- 125--------- 118--------- 110.6
0.0490---- 127.5------- 120--------- 112.5
0.0500---- 130--------- 122--------- 114.4
Mahalo to all that contribute.
-----------------------------------------------------------------------------------------------------------------
YEAR:
INTAKE MODIFICATIONS:
EXHAUST MODIFICATIONS:
JET KIT OR STOCK?
BRAND OF JET KIT?
MAIN JET:
NEEDLE AND CLIP POSITION:
MIXTURE SCREW SETTINGS:
ELEVATION:
MISCELLANEOUS INFORMATION ABOUT YOUR BIKE’S JETTING SETUP:
.
