11-22-2014, 10:22 PM
(This post was last modified: 04-03-2015, 08:39 AM by Chief_Mechanic.)
Note: This thread is for jetting specs only; jetting discussion can continue in the Jetting Discussion Thread.
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 bike's ride-ability. Your contributions are what will make this a valuable tool for anyone looking to rejet their bike in the future.
Benefits of rejetting...
With rejetting, it is possible to extract more power out of the little 250 motor. 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 area at the bottom of this post into your reply to help start building a jetting database in the SRV250 forum. As much as possible, please stay on topic 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. (Don't forget that jetting discussions are to be held in the Jetting Discussions forum.)
As a baseline, these are the stock 1994 jetting specs from the service manual-
Carburetion
I.D.Mark - 4DN01
MAIN JET - #97.5 (Anybody know the manufacturer for the stock jets?)
MAIN AIR JET - #100
PILOT JET 1 - #15
PILOT AIR JET - #130
JET NEEDLE – 4FEZ4-3/5
PILOT SCREW - 1-1/2 turns out
THROTTLE VALVE - 135
ENGINE IDLE SPEED - 1,250 ~ 1,350 r/min
FUEL LEVEL - 4 ~ 5 mm
---------------------------------------------------------------------------------------
Here are some main jet conversions between manufacturers-
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
-----------------------------------------------------------------------------------------------
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:
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 bike's ride-ability. Your contributions are what will make this a valuable tool for anyone looking to rejet their bike in the future.
Benefits of rejetting...
With rejetting, it is possible to extract more power out of the little 250 motor. 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 area at the bottom of this post into your reply to help start building a jetting database in the SRV250 forum. As much as possible, please stay on topic 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. (Don't forget that jetting discussions are to be held in the Jetting Discussions forum.)
As a baseline, these are the stock 1994 jetting specs from the service manual-
Carburetion
I.D.Mark - 4DN01
MAIN JET - #97.5 (Anybody know the manufacturer for the stock jets?)
MAIN AIR JET - #100
PILOT JET 1 - #15
PILOT AIR JET - #130
JET NEEDLE – 4FEZ4-3/5
PILOT SCREW - 1-1/2 turns out
THROTTLE VALVE - 135
ENGINE IDLE SPEED - 1,250 ~ 1,350 r/min
FUEL LEVEL - 4 ~ 5 mm
---------------------------------------------------------------------------------------
Here are some main jet conversions between manufacturers-
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
-----------------------------------------------------------------------------------------------
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: