James Dean
Member
- May 17, 2000
- 137
- 0
--------------------------------------------------------------------------------
Take 30 years of dirt biking experience and a mechanical engineering degree and put them together. Then ask if there is a better way to understand and make jetting changes on dirt bikes.
******
See: www.JDJetting.com
******
This Keihin jetting guide is now available to everyone and is unlike any before.
The Excel spreadsheet uses tables within the program to graph the needle profile (diameter) at the nozzle and show the relative change in jet orifice area from one setup to another.
The relative change in jetting is shown versus throttle position for all of these components:
-Pilot jet
-Needle diameter
-Clip position
-L1 dimension
-Taper
-Main jet
Additional correction factors are included to adjust for:
-Altitude
-Temperature
All of the components along with altitude and temperature are combined into a single "Relative Change" graph. The spreadsheet takes into account overlapping circuits and the transition between the needle and main jet mathematically.
All of the 2002 250 MX carb needles have been measured and tabulated in the spreadsheet: NOZE, N3WE, N8RH, N3EJ, NAFF, and the R11xxx, R13xxx, R14xxx needles.
There are over 200 Keihin replacement needles available between the FCR and PWK/PWM/PJ carburetors.These are all coded into the program. Also, a refined list of the most useful ones for ease of selection showing rich versus lean choices. With all the possible clip positions, pilot, and main jet combinations, literally thousands of settings can be evaluated.
If you ever want to do jetting, you need to see this first. The methods have been around for at least 20 years, but nobody has ever tried quantify and share them before. :eek:
James Dean
Take 30 years of dirt biking experience and a mechanical engineering degree and put them together. Then ask if there is a better way to understand and make jetting changes on dirt bikes.
******
See: www.JDJetting.com
******
This Keihin jetting guide is now available to everyone and is unlike any before.
The Excel spreadsheet uses tables within the program to graph the needle profile (diameter) at the nozzle and show the relative change in jet orifice area from one setup to another.
The relative change in jetting is shown versus throttle position for all of these components:
-Pilot jet
-Needle diameter
-Clip position
-L1 dimension
-Taper
-Main jet
Additional correction factors are included to adjust for:
-Altitude
-Temperature
All of the components along with altitude and temperature are combined into a single "Relative Change" graph. The spreadsheet takes into account overlapping circuits and the transition between the needle and main jet mathematically.
All of the 2002 250 MX carb needles have been measured and tabulated in the spreadsheet: NOZE, N3WE, N8RH, N3EJ, NAFF, and the R11xxx, R13xxx, R14xxx needles.
There are over 200 Keihin replacement needles available between the FCR and PWK/PWM/PJ carburetors.These are all coded into the program. Also, a refined list of the most useful ones for ease of selection showing rich versus lean choices. With all the possible clip positions, pilot, and main jet combinations, literally thousands of settings can be evaluated.
If you ever want to do jetting, you need to see this first. The methods have been around for at least 20 years, but nobody has ever tried quantify and share them before. :eek:
James Dean
Last edited: