Buell 2002 X1 Handbook page 137

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ENGINE
GENERAL
TM
The Thunderstorm high performance engine is a two-cylin-
der, four-cycle, air-cooled, overhead-valve V-twin. It has three
major component assemblies.
Cylinder
The cylinder assembly includes cylinder head, valves, rocker
arm cover, rocker arms and piston. Cylinders mount on the
crankcase in a 45 degree "V" with both connecting rods con-
nected to a single crank pin.
Thunderstorm engines have modified cylinder heads with a
black finish and unique pistons.
Crankcase
The up-and-down motion of the piston in the cylinder is con-
verted to circular motion in the crankcase. The multi-piece
crankshaft consists of a crank pin mounted between two
counterweighted flywheels, which rotate on two end shaft
bearings. The lower end of the rear cylinder connecting rod is
forked to fit around the single-end front cylinder connecting
rod, allowing a single connecting rod crank pin connection to
the flywheel.
Gearcase
The gearcase is located on the right side of the crankcase.
The gearcase houses the gear train, which operates and
times the valves and ignition. The cam gear train, consisting
of four cam shafts with one cam lobe on each shaft, is gear
driven. The engine valves are opened and closed through the
mechanical linkage of hydraulic lifters, push rods and rocker
arms. Hydraulic lifters, located in the lifter bores, automati-
cally compensate for heat expansion to maintain the no-lash
fit of valve train components. Hydraulic lifters and pushrods
transmit the cam action to the valve linkage. Valve timing is
obtained by aligning timing marks when installing cam gears.
Ignition spark is produced by the operation of a microproces-
sor-controlled electronic control module (ECM), ignition coil
and spark plugs. Spark timing is determined by a trigger
rotor, magnetic sensing unit and the ECM.
The trigger rotor has six openings which time the cylinders
and communicate engine speed to the ECM.
The spark plugs fire independently during the compression
stroke on each cylinder (no waste spark).
2002 Buell X1: Engine
FUEL
Gasoline/Alcohol Blends
Buell motorcycles were designed to obtain the best perfor-
mance and efficiency using unleaded gasoline (91 pump
octane or higher). Some fuel suppliers sell gasoline/alcohol
blends as a fuel. The type and amount of alcohol added to the
fuel is important.
DO NOT USE GASOLINES CONTAINING METHANOL.
G
Using gasoline/methanol blends will result in starting and
driveability deterioration and damage to critical fuel sys-
tem components.
ETHANOL is a mixture of 10% ethanol (Grain alcohol)
G
and 90% unleaded gasoline. Gasoline/ethanol blends
can be used in your motorcycle if the ethanol content
does not exceed 10%.
Gasolines containing ETHER: Gasoline/ether blends are
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a mixture of gasoline and as much as 15% ether. Gaso-
line/ether blends can be used in your motorcycle if the
ether content does not exceed 17%.
REFORMULATED OR OXYGENATED GASOLINES
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(RFG): "Reformulated gasoline" is a term used to
describe gasoline blends that are specifically designed
to burn cleaner than other types of gasoline, leaving
fewer "tailpipe" emissions. They are also formulated to
evaporate less when you are filling your tank. Reformu-
lated gasolines use additives to "oxygenate" the gas.
Your motorcycle will run normally using this type of gas.
Buell recommends you use it when possible, as an aid to
cleaner air in our environment.
Because of their generally higher volatility, these blends may
adversely affect the starting, driveability and fuel efficiency of
your motorcycle. If you experience these problems, Buell rec-
ommends you operate your motorcycle on straight, unleaded
gasoline.
LUBRICATION
The engine has a force-feed (pressure) type oiling system,
incorporating oil feed and return pumps in one pump body, with
one check valve on the oil feed side. The feed pump forces oil
to the engine, lubricating lower connecting rod bearings, rocker
arm bushings, valve stems, valve springs, push rods and
hydraulic lifters. Cylinder walls, pistons, piston pins, timing
gears and bushings and main bearings are lubricated by oil
spray thrown off connecting rods and crankshaft, and by oil
draining from each rocker box through an internal drain pas-
sage in each cylinder and each lifter guide. A small amount of
oil is sprayed through an oil galley jet onto the rear intake cam
gear in the gearcase; oil is transferred to the teeth of all the
cam gears by way of the gear meshing action. The oil-scav-
enging section of the pump returns oil to the tank from the
engine. See 3.7 LUBRICATION SYSTEM
3.2
for more information.
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