Honda CRF450R 2019 User Manual

Servicing Your Honda 87
Valve Clearance
6. Lift the rocker arms (12) up and remove the
shims (13).
Be careful not to damage the intake rocker arms.
Do not clean the intake rocker arms using a
commercially available compound cleaner.
1. Measure the shim thickness with a micrometer
and record it.
Seventy-three different shims (1) are available
in 0.025 mm thickness intervals, from 1.200
mm (the thinnest) to 3.000 mm (the thickest).
2. Calculate the new shim thickness using the
equation below.
A = (B – C) + D
A: New shim thickness
B: Recorded valve clearance
C: Specified valve clearance
D: Old shim thickness
• Make sure of the correct shim thickness by
measuring the shim with a micrometer.
• Reface the exhaust valve seat if carbon deposits
result in a calculated dimension of over 3.000
mm.
Do not lap the intake valves. They are titanium and
have a thin oxide coating. Lapping will damage
this coating.
If a calculated dimension is out of specifications,
have your motorcycle inspected by your dealer.
(12) rocker arms
(13) shims
(13)
(12)
(13)
(12)
Shim Selection
(1) shim
(1)
1.80 mm 1.825 mm 1.85 mm
1.875 mm
3RMKE630_CRF450RX-L.book Page 87 Friday, April 5, 2019 5:55 PM

Honda CRF450R 2019 Specifications

General

Engine Type	449cc liquid-cooled single-cylinder four-stroke
Bore x Stroke	96.0mm x 62.1mm
Compression Ratio	13.5:1
Induction	Programmed Fuel Injection (PGM-FI), 46mm throttle body
Ignition	Full transistorized ignition
Final Drive	#520 chain; 13T/49T
Front Brake	Single 260mm disc with twin-piston caliper
Rear Brake	Single 240mm disc
Front Tire	80/100-21
Rear Tire	120/80-19
Trail	116mm (4.6 inches)
Wheelbase	58.3 inches
Seat Height	37.8 inches
Ground Clearance	13.0 inches
Valve Train	Unicam
Transmission	5-speed
Rear Suspension	12.4 inches travel
Curb Weight	247 pounds