Installation; Tuning And Adjustment; Carburetor Tuning Data - Yamaha BR250F Service Manual

9. Apply grease to the following areas so
they will not freeze:
Throttle return spring,
Throttle shaft,
Both spaces between the throttle shaft
and carburetor body,
Throttle lock washer,
E~c1ip, and
The wire holder attached to the throttle
valve.
E. Installation
1. Install the carburetor in the engine. Be
sure the air box boot and the carburetor
boot correctly engage the carburetor.
Secure the clamp on the carbu retor
boot, and carefully secure the air box
boot spring.
Do not overstrech the air box boot spring.
The spring can be damaged and will have to
be replaced.
2. Attach the throttle cable, starter cable,
oil pump cable, oil del ivery line, and the
pulse pipe. Refer to the Cable Routing
Diagram in the appendix.
2. High altitude tuning
3-2. Tuning and Adjustment
The carburetor is set at the factory to run at
temperatures of 32° F to _4° F (0° to -20°C)
at seal level. If the machine has to be operated
under conditions other than specified above,
the carburetor must be reset as required.
Special care should be taken in carburetor
setting so that the piston will not be damaged
or seized.
A. Carburetor Tuning Data
1. Standard specification
Carburetor BD32·28/KEIHIN
1.0. Mark 8R401
Main jet #108
Slow adjuster (turn out) 1·1/4
Starter jet. #120
Slow jet #78
15 ± 2.0 mm
Float height
(0.59 ± 0.08 in)
~
-30°C -20°C -10
0
e
O°C 10°C 20
0
e
(-22°F)
(_4°F)
(14°F) (32°F) (50°F) (68°F)
Altitude
I I J I I
I ..
#105
It'
Seal level
..
#108
..
.......-#112 .....
....
#105
...
"" 600 m (200
tt)
..
#108
...
...#102 ....
"" 1200 m (4000
ft)
. .
#105
..
"""'-'#108
...
...
#102
..
"" 1800 m (6000
ft)
..
#105
..
.....--#108 .....
......#100....
"" 2400 m (8000
ft]
..
#102
...
"""'-#105
...
"" 3000 m or more
..
#100
It'
(10000
ft)
..
#102
...
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