Gilera DNA 50, Workshop Manual

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This section makes it possible to find the solutions to use in troubleshooting.
For each breakdown, a list of the possible causes and respective interventions is given.
Engine
Poor performance
POOR PERFORMANCE
Possible Cause Operation
Defective fuel pump or damaged depression line Replace the pump or control lines
Carburettor nozzles clogged or dirty Dismantle, wash with solvent and dry with compressed air
Fuel filter on the tank outlet fitting dirty or clogged Clean the fitting filter
Excess of encrustations in the combustion chamber Remove the encrustations
Lack of compression wear of the piston rings or cylinder Check the worn parts and replace them
Exhaust pipe clogged due to excessive encrustations Replace the exhaust pipe and check the carburation and mixer
timer
Air filter blocked or dirty Clean according to the procedure
Starter inefficient (stays on) Check the mechanical sliding, continuity of the circuit, the pres-
ence of power and electrical wiring
Clutch slipping Check the centrifugal brake shoe assembly and /or clutch bell
and replace if necessary
Defective mobile pulley sliding Check the parts, change the faulty parts and lubricate the driv-
en pulley using only Montblanc-Molibdenum Grease (dis.
498345) grease
Transmission belt worn Replace
Roller wear; Presence of oil; Dirt Clean the speed variator, replace the rollers if worn out
Rear wheel spins at idle
REAR WHEEL
Possible Cause Operation
Idling rpms too high Check the idling speed and, if necessary, adjust the C.O.
Clutch fault Check the spring/friction mass and the clutch bell
Air filter housing not sealed Correctly refit the filter housing and replace it if it is damaged
Starting difficulties
DIFFICULTY STARTING
Possible Cause Operation
Carburettor nozzles clogged or dirty Dismantle, wash with solvent and dry with compressed air
Defective fuel pump or damaged depression line Replace the pump or control lines
Starter inefficient Check: electric wiring, circuit continuity, mechanical sliding and
power supply
Battery flat Check the state of the battery. If it shows signs of sulphation
replace it and bring the new battery into service charging it for
eight hours at a current of 1/10 of the capacity of the battery
itself
- Engine flooded. Start up keeping the throttle fully open alternating approximate-
ly five seconds of turning it with five seconds still. If however it
does not start, remove the spark plug, the engine over with the
throttle open being careful 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
Defective spark plug or with incorrect electrode gap Remove the encrustation, restore the plug gap or replace being
sure to use the types of spark plug recommended at all times.
Troubleshooting
DNA 50
TROUBL - 36