Honda CRF450R User Manual

Carburetor Adjustments & Tuning Tips
126 Adjustments for Competition
Standard Tuning Recommendations
For the following recommendations to be
accurate, you must use the standard settings as a
baseline. Also, don’t change any of the settings
until you’ve determined what changes are
necessary.
Adjustment
Pilot screw opening
Slow jet
Jet needle
Needle clip position
Main jet
Float level
Identification number
Standard settings
1 7/8 turns out
#42
NGGQ
4th groove
#168
0.31 in (8.0 mm)
FCR00D
Adjustments for Altitude & Temperature
All jetting recommendations are based on
standard jetting with an unmodified engine. The
following conditions can affect the fuel mixture.
Condition
cold temperature
warm temperature
dry air
high humidity
high altitude
Mixture will be:
lean
rich
lean
rich
rich
Adjust to:
richer
leaner
richer
leaner
leaner
All jetting is based on
• Standard jetting
• Unmodified Engine
Legend
PS: Pilot Screw opening from fully seated
SJ: Slow Jet
JN CLIP: Needle Clip position
JN: Jet Needle
MJ: Main Jet
TEMPERATURE
ALTITUDE
10,000 ft
(3,050 m)
to
7,500 ft
(2,300 m)
7,499 ft
(2,299 m)
to
5,000 ft
(1,500 m)
4,999 ft
(1,499 m)
to
2,500 ft
(750 m)
2,499 ft
(749 m)
to
1,000 ft
(300 m)
999 ft
(299 m)
to
Sea level
PS:
SJ:
JN CLIP:
JN:
MJ:
1 7/8
42
4th
NGGQ
168
1 7/8
42
4th
NGGQ
165
1 5/8
42
3rd
NGGQ
165
1 5/8
42
3rd
NGGQ
162
1 5/8
40
3rd
NGGQ
162
1 3/8
40
3rd
NGGQ
160
1 3/8
40
3rd
NGGQ
160
PS:
SJ:
JN CLIP:
JN:
MJ:
1 7/8
42
4th
NGGQ
170
1 7/8
42
4th
NGGQ
168
1 7/8
42
4th
NGGQ
165
1 5/8
42
3rd
NGGQ
165
1 5/8
42
3rd
NGGQ
162
1 5/8
40
3rd
NGGQ
162
1 3/8
40
3rd
NGGQ
160
PS:
SJ:
JN CLIP:
JN:
MJ:
2 1/8
42
5th
NGGQ
170
1 7/8
42
4th
NGGQ
170
1 7/8
42
4th
NGGQ
168
1 7/8
42
4th
NGGQ
165
1 5/8
42
3rd
NGGQ
165
1 5/8
42
3rd
NGGQ
162
1 5/8
42
3rd
NGGQ
162
PS:
SJ:
JN CLIP:
JN:
MJ:
2 1/8
45
5th
NGGQ
172
2 1/8
42
5th
NGGQ
170
1 7/8
42
4th
NGGQ
170
1 7/8
42
4th
NGGQ
168
1 7/8
42
4th
NGGQ
165
1 5/8
42
3rd
NGGQ
165
1 5/8
42
3rd
NGGQ
162
PS:
SJ:
JN CLIP:
JN:
MJ:
2 1/8
45
5th
NGGQ
172
2 1/8
45
5th
NGGQ
172
2 1/8
42
5th
NGGQ
170
1 7/8
42
4th
NGGQ
170
1 7/8
42
4th
NGGQ
168
1 7/8
42
4th
NGGQ
165
1 5/8
42
3rd
NGGQ
165
CENT
FAHR
–30°~ –17°
–21°~ 0°
–18°~ –6°
–1°~ –20°
–7°~ 5°
19°~ 40°
4°~ 16°
39°~ 60°
15°~ 27°
59°~ 80°
26°~ 38°
79°~ 100°
37°~ 49°
99°~ 120°
STANDARD
JETTING

Honda CRF450R Specifications

General

Brand	Honda
Model	CRF450R
Category	Motorcycle
Language	English