Evaporative Emissions Control System - Buell P3 2003 Service Manual

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EVAPORATIVE EMISSIONS CONTROL SYSTEM

GENERAL
See Figure 4-22. Buell motorcycles sold in the state of Cali-
fornia are equipped with an evaporative (EVAP) emissions
control system. In conformance with California Air Resource
Board (CARB) regulations, the EVAP system prevents both
fuel and crankcase vapors from escaping into the atmo-
sphere.
The EVAP system functions as follows:
The fuel vapor vent tube connected to the fitting at the
front of the fuel cap flange allows fuel vapors in the fuel
tank to be vented through the rollover valve to the char-
coal canister. If the vehicle is tipped, the rollover valve
also prevents the loss of gasoline through the vent tube.
When the engine is running, negative pressure (vacuum)
created at the carburetor venturi draws the fuel vapors
stored in the charcoal canister through the purge hose
to the carburetor where they are burned as part of the
normal combustion process.
Fuel vapors emanating from the carburetor throat are
drawn to the charcoal canister through a fitting on the
PCV outlet hose. A preformed hose on one end of the
a0187a4x
1. 3-Way fitting
2. Carburetor
3. PCV valve
4. Fuel line
5. Fuel valve
6. Rollover valve
7. Vent tube fitting
8. Fuel tank
9. Vent tube
10. Purge tube
11. To "carb"
12. To "fuel tank"
13. Charcoal canister
14. PCV outlet hose
15. Venturi ring
16. Breather hose
Figure 4-22. California Evaporative Emissions Control System Schematic
4-24 2003 Buell P3: Fuel System
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fitting is fixed to an allen head screw on the venturi ring
for positive location.
Crankcase vapors passing through the PCV valve follow
the fuel vapors to the charcoal canister via a 3-way fitting
plumbed into the PCV outlet hose. The fuel and crank-
case vapors, after passing through the charcoal canister,
travel through the purge hose to the carburetor, and like
the vapors from the fuel tank, are burned during combus-
tion.
Verify that the vent tubes and hoses do not contact hot
exhaust or engine parts. Tubes contain flammable vapors
that can be ignited if damaged, possibly causing fire or
explosion, which could result in death or serious injury.
The EVAP system has been designed to operate with a mini-
mum of maintenance. Check that all hoses are correctly
routed and properly connected. Also, verify that the hoses are
not pinched or kinked.
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WARNING WARNING
NOTE
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