Buell S1 Lightning User Manual

3-32
CRANKCASE BREATHING SYSTEM
GENERAL
See Figure 3-43. On piston downstroke, a mixture of crankcase
air and oil mist is vented up the push rod covers (1) through an
umbrella valve (3) in each middle rocker box section. The oil
mist separates from the crankcase air, collects and passes
through a small drain hole (2) where it eventually returns to the
crankcase. The crankcase air is routed through a passage in
each cylinder head. The crankcase air then travels through
each air cleaner breather bolt (4) into a hose leading into the
air cleaner.
Figure 3-43. Crankcase Breathing System – Typical Cylinder
1. Push rod cover (2)
2. Oil drain hole
3. Umbrella valve
4. Breather bolt
b0143a3x
1
4
3
2

Buell S1 Lightning Specifications

General

Transmission	5-speed
Rear Brakes	Single 230mm disc, single-piston caliper
Compression Ratio	10.0:1
Ignition	Electronic
Engine Type	Air-cooled, four-stroke, 45° V-twin
Rear Suspension	Showa monoshock, adjustable preload, compression and rebound damping
Front Brakes	Single 340mm disc, 6-piston caliper
Seat Height	775 mm
Bore x Stroke	88.8 mm x 96.8 mm
Fuel System	Carburetor
Frame	Tubular steel
Tires	Front: 120/70 ZR17, Rear: 170/60 ZR17