2002-2003 Bombardier Baja DS650 Service Manual, Page 52Get this manual
Section 03 ENGINE Subsection 02 (TROUBLESHOOTING)
ENGINE GENERAL
SYMPTOM CONDITION TestInspection ENGINE BACKFIRESNORMAL USE1Check spark plug andor electrical systemaCarbon accumulation caused by defective spark plugClean carbon accumulation and replace spark plugbElectrical system has failureReplace defective part(s)2Check leakage on intake manifoldaAir leak on intake systemRetighten screws andor replace intake manifold3Check exhaust air leakingaExhaust gasket is leakingRetighten screws andor replace exhaust gasket4Check intake valve(s) for leakingaIntake valve(s) is(are) leakingRepair or replace valve(s)5Check if fuel supply is to less at high RPMaFuel line is contaminated andor bent (engine gets lean)Clean andor replace defective part(s)SYMPTOM CONDITION TestInspection ENGINE SUDDENLY TURNS OFFNORMAL USE1Perform engine leak testRefer to ENGINE LEAK TEST procedureCheck for possible piston seizureaDamaged head gasket andor seal andor leaking inletexhaust valve(s)Replace andor repair defective parts2"Four-corner" seizure of pistonaAccelerating too fast when engine is coldPiston expands faster than cylinderReplace pistonsAsk driver to refer to warm-up procedure in Operator's Guide3Piston seizure (arrow to piston exhaust side)aSpark plug heat range is too warmInstall spark plug with appropriate heat range (refer to TECHNICAL DATA)bImproper ignition timingReplace failed part(s) in electrical system (electronic module)cCompression ratio is too highInstall genuine partsdPoor oil qualityUse BOMBARDIER recommended oileLeaks at air intake manifold (engine gets too lean)Retighten screws or replace air intake manifold