2004 Bombardier DS650/DS650 Baja/DS650 Baja X Shop Manual, Page 160Get this manual
Section 05 ELECTRICAL Subsection 05 (IGNITION SYSTEM)
SPARK PLUG DISASSEMBLY
Unplug the spark plug cable Unscrew the spark plug one turnClean the spark plug and cylinder head with pressurized air then completely unscrew
SPARK PLUG INSTALLATION
CAUTION: Always use the recommended spark plugPrior to installation make sure that contact surfaces of the cylinder head and spark plug are free of grime1Using wire feeler gauge, set electrode gap according to the following chart2Apply anti-seize lubricant over the spark plug threads to prevent possible seizure3Hand screw spark plug into cylinder head and tighten with torque wrench and proper socket
FOULING
Fouling of the spark plug is indicated by irregular running of the engine, decreased engine speed due to misfiring, reduced performance, and increased fuel consumptionThis is due to loss of compressionOther possible causes are: prolonged idling or low-speed riding, or running on too rich mixture due to abuse of choke, clogged air filter, faulty carburetor adjustment, incorrect fuel, defective ignition system, incorrect ignition timing, incorrect spark plug gap, lubricating oil entering the combustion chamber, or too cold spark plugThe plug face of fouled spark plug has either wet black deposit or black carbon foulingSuch coatings form conductive connection between the center electrode and ground