Derbi BOULEVARD 50 2T, Workshop Manual

Page: 38 / 154

Possible Cause Operation
to keep the cap in contact with the spark plug and the spark
plug grounded but away from its hole. Refit a dry spark plug
and start the vehicle.
Altered fuel characteristics Drain off the fuel no longer up to standard; then, refill
Faulty spark plug Remove the encrustation, restore the plug gap or replace being
sure to use the types of spark plug recommended at all times.
Bear in mind that many problems engines have, derive from
the use of the wrong spark plug
Intake joint cracked or with a bad seal Replace intake joint and check for correct sealing on the head
Purifier-carburettor fitting damaged Replace
Excessive oil consumption/Exhaust smoke
EXCESSIVE OIL CONSUMPTION/SMOKEY EXHAUST
Possible Cause Operation
Excess of encrustations in the combustion chamber Remove the encrustations
Engine tends to cut-off at full throttle
ENGINE STOP FULL THROTTLE
Possible Cause Operation
Maximum nozzle dirty - lean mixture Wash the nozzle with solvent and dry with compressed air
Dirty carburettor Wash the carburettor with solvent and dry with compressed air
Water in the carburettor Empty the tank through the appropriate bleed nipple.
Air filter dirty Clean or replace
Defective floating valve Check the proper sliding of the float and the functioning of the
valve
Tank breather hole obstructed Restore the proper reservoir aeration
Engine tends to cut-off at idle
ENGINE STOP IDLING
Possible Cause Operation
Minimum nozzle dirty Wash the nozzle with solvent and dry with compressed air
Starter that stays open Check: electric wiring, circuit continuity, mechanical sliding and
power supply
Reed valve does not close Check / replace the reed pack
Wrong idling adjustment Correctly adjust the engine idling and check the level of the
C.O.
Spark plug defective or faulty Replace the spark plug with one with the specified degree and
check the plug gap
Excessive exhaust noise
INCREASED NOISINESS
Possible Cause Operation
Secondary metal air pipe deteriorated Check there are no leaks on the hoses on the crankcase and
the housing, check that there is a cap with filter and it is correctly
fitted to the transmission cover
Good condition of the missing secondary air circuit components Check the individual components and the piping, check the
precision of the fitting. Replace the damaged components
Troubleshooting
TROUBL - 38