Royal Enfield Bullet Classic EFI Service Manual page 215

Observation
Poor Cranking
Complaint : Engine starts but switches OFF
General
Fuel Related
Electricals Related
Complaint : Idling Erratic / high
General
Causes
Loose spark plug
Loose cylinder head nuts
Blown cylinder head gasket
Auto Decompressor mechanism stuck in
open position
Valves Leaking due to poor seating/burnt
valves or seats
Piston Rings Worn out
Worn out / scored/ glazed cylinder barrel
Piston rings stuck in piston grooves
Idling RPM low
Fuel is stale due to vehicle being in
storage for a long period
Fuel adulterated
Fuel level very low in tank
Vent hole clogged in fuel tank cap
Fuel Line Clogged
Fuel hose cracked resulting in fuel leaking
out and not getting supplied to injector
Fuel pump pressure insufficient/fuel pump
not working
Fuel Injector partially blocked
Loose / damaged throttle body to engine
hose / air filter to throttle body
Weak Battery
Electrical connections Loose
Incorrect Electrode gap
Spark plug electrode dirty / fouled
Wrong specification spark plug
Loose HT connections/ damaged HT lead
Idling RPM High
No throttle cable free play
Stuck throttle inner cable
Loose / damaged throttle body to engine
hose / air filter to throttle body
Suction leakage
Remedies
Tighten spark plug
Tighten cylinder head nuts
Change cylinder head gasket
Ensure flyweight in exhaust cam
gear assembly in free to operate.
Check & Correct
Replace piston rings
Replace cylinder barrel/piston
Clean, check and refit/replace
piston rings
Adjust the idle air bypass screw
in the throttle body
Clean petrol tank and carburetor
and fill the tank with fresh petrol
Refill with good fuel
Fill up the tank
Clean vent hole.
Clean the fuel line.
Check and replace
Check fuel pump coupler
connection/ Check fuel pump
relay for proper working
Replace fuel injector.
Check and correct
Charge / Replace the battery
Check & Correct
Adjust the gap
Clean park plug & Reset gap.
Fit the correct Spark Plug
Fix connections firmly/ Replace
Lead.
Adjust the idle air bypass screw
in the throttle body
Adjust throttle cable free play
Clean / Replace cable
Tighten / replace the hose
Check and correct
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