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Recommended Jetting for Bing Carburetors
The following is the factory recommended jet for Bing carburetors at sea level and 70F
degrees. Apply the Bing Main Jet Correction Chart shown at the bottom of the page to
compensate for temperature and altitude at your location. Jetting for engines equipped
with intake silencers are also listed.
Rotax Engines w/o Intake Silencer
| Engine Type |
Main
Jet |
Idler
Jet |
Needle
Jet |
Jet
Needle |
Clip from top
|
Air
Screw
|
| Rotax 277 |
148 |
45 |
2.72 |
8L2 |
2 |
1.0 |
| Rotax 377 |
165 |
45 |
2.70 |
8O2 |
2 |
0.5 |
| Rotax 447 |
165 |
45 |
2.70 |
15K2 |
2 |
0.5 |
| Rotax 447 DC |
135 |
50 |
2.70 |
6G1 |
3 |
1.0 |
Rotax 503 SC
Up to Serial #3785371 |
180 |
45 |
2.74 |
8G2 |
3 |
0.5 |
Rotax 503 SC
After Serial #3785372 |
185 |
45 |
2.72 |
15K2 |
3 |
0.5 |
| Rotax 503 DC |
158 |
45 |
2.70 |
11K2 |
2 |
0.5 |
| Rotax 532 SC |
195 |
55 |
2.74 |
15K2 |
3 |
1.0 |
| Rotax 532/582 DC |
165 |
55 |
2.72 |
11G2 |
3 |
1.0 |
| Rotax 618 DC |
158 |
55 |
2.72 |
15E5U |
3 |
1.0 |
Rotax Engines with Intake Silencer
-NOTE-
I personally do not recommend the use of the intake silencer
it reduces horsepower and is generally ineffective in noise reduction ! !
| Engine Type |
Main Jet |
Idler Jet |
Needle
Jet |
Jet
Needle |
Clip |
Airscrew |
| Rotax 277 |
140 |
45 |
2.72 |
8L2 |
2 |
1.0 |
| Rotax 377 |
155 |
45 |
2.70 |
8O2 |
2 |
0.5 |
| Rotax 447 |
155 |
45 |
2.70 |
15K2 |
2 |
0.5 |
| Rotax 447 DC |
128 |
50 |
2.68 |
15K2 |
2 |
1.0 |
Rotax 503 SC
UP to Serial #3785371 |
158 |
45 |
2.74 |
6H2 |
3 |
0.5 |
Rotax 503 SC
After Serial #3785372 |
165 |
45 |
2.70 |
15K2 |
3 |
0.5 |
| Rotax 503 DC |
148 |
45 |
2.68 |
11K2 |
2 |
1.0 |
| Rotax 532 SC |
170 |
55 |
2.74 |
15K2 |
3 |
1.0 |
| Rotax 532/582 DC |
145 |
55 |
2.68 |
15K2 |
3 |
1.0 |
| Rotax 618 DC |
135 |
55 |
2.70 |
15E5U |
3 |
1.0 |
Bing Correction Chart
How to Use the Bing Main Jet Correction Chart
Step #1 - Assume Nothing!!! (ASSUME-makes an ASS out of U and
ME) -Disassemble and check your carburetor(s) to verify the recommended jetting
listed in the recommended Bing jetting chart is installed in your Carb(s). This is the
most up to date information available at the time of this publication.
Step #2 - Because air density varies with temperature and altitude changes, a main jet
correction may be necessary. This chart was calculated at sea level with an air
temperature of 60F or 15C.
Step #3 - Apply the multiplication factor shown to the main jet size recommended in the
chart at the top of the page.
Step #4 - Your operating conditions will vary by the change of seasons. If your EGT T
temps vary and your engine experiences performance difficulties, a review of your jetting
may be necessary. Return to step #2.
Step #5 - Humidity is also a variable in determining air density. A high humidity means
a lower air density of air to be consumed by combustion. Because we are generally not
equipped with a way of easily reading the % of humidity present, this can be read in to
this chart by adding altitude on high humidity days and subtracting altitude on in very
dry climates. An EGT gauge should illustrate changes in these conditions under lull
throttle readings.
Main Jet Correction Chart ................
Example: 160 x 0.89= 142 Main Jet
| Altitude - Meters |
0m |
500m |
1000 |
1500 |
2000 |
2500 |
3000 |
3500 |
4000 |
| - Feet |
0' |
1500' |
3000' |
4500' |
6000' |
7500' |
9000' |
10500' |
12000' |
| Temperature |
|
|
|
|
|
|
|
|
|
| -22F -30C |
1.04 |
1.03 |
1.01 |
1.00 |
0.98 |
0.97 |
0.95 |
0.94 |
0.93 |
| -4F -20C |
1.03 |
1.02 |
1.00 |
0.99 |
0.97 |
0.96 |
0.95 |
0.93 |
0.92 |
| 14F -10C |
1.02 |
1.01 |
0.99 |
0.98 |
0.96 |
0.95 |
0.94 |
0.92 |
0.91 |
| 32F 0C |
1.01 |
1.00 |
0.98 |
0.97 |
0.95 |
0.94 |
0.93 |
0.91 |
0.90 |
| 50F 10C |
1.00 |
0.99 |
0.97 |
0.96 |
0.95 |
0.93 |
0.91 |
0.90 |
0.88 |
| 59F 15C |
1.00 |
0.99 |
0.97 |
0.96 |
0.94 |
0.93 |
0.92 |
0.90 |
0.88 |
| 68F 20C |
1.00 |
0.98 |
0.97 |
0.95 |
0.94 |
0.93 |
0.91 |
0.90 |
0.88 |
| 86F 30C |
0.99 |
0.97 |
0.96 |
0.94 |
0.93 |
0.92 |
0.90 |
0.89 |
0.88 |
| 104F 40C |
0.98 |
0.96 |
0.95 |
0.94 |
0.92 |
0.91 |
0.90 |
0.88 |
0.87 |
| 123F 50C |
0.97 |
0.96 |
0.94 |
0.93 |
0.92 |
0.90 |
0.89 |
0.88 |
0.86 |
Note:
Before operating the engine again at lower altitudes, reinstallation of the original
jetting is necessary or engine damage or failure may occur!
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