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Electrical Starting Problems & Diagnosis
Weak battery symptoms:
-- Slow cranking.
-- Stops cranking suddenly on compression stroke with button pressed.
-- Starts when starter button is released at end of cranking.
Repair:
-- Charge/Test/Replace battery.
Failure Modes:
-- Loss of capacity. Appears to charge, voltage good but no reserve for starting.
-- Won't hold a charge.
-- Low voltage/cell failure.
Preventative Maintenance:
-- Check fluid levels regularly
-- Maintain full charge: Regular riding, trickle charger.
Ignition Coil failure symptoms:
-- Hard starting/misfiring during cranking.
-- Rough idle that can't be tuned out with carb adjustments and carb cleaning.
-- Idle misfire clears with new sparkplugs, returns in a few hundred miles
Repair:
-- Replace: Preferably with Nology for higher reliability than stock Gill coils.
Failure Mode:
-- Shorted turns in secondary resulting in weak spark.
Preventative Maintenance:
-- None
Testing:
-- Replace sparkplugs.
-- Hang a spare plug off the plug wires. Fat blue spark = good, thin yellow spark = bad.
Pickup Coil failure symptoms:
-- No spark at all
-- Spark quits with engine hot, returns when engine cool.
-- Note: Pickup coil failure is total. There is no random misfire spark loss.
Repair:
-- Replace pickup coil
Failure mode:
-- Thermal intermittant with long (15-30 minute) period.
Preventative Maintenance:
-- None. Get a spare.
Testing:
-- Ohms checks hot and cold.
Worn starter symptoms:
-- Sometimes won't crank until the bike is rocked in gear.
-- Excessively noisy cranking with a grinding sound.
-- Click from under seat but no cranking.
Failure Mode:
-- Brush wear progressing to commutator damage.
-- Bearing failure related to brush wear.
Repair:
-- Rebuild or replace.
Preventative Maintenance:
-- Maintan battery in peak condition.
-- Follow proper starting procedures. Neutral, clutch in.
-- Crank 5-10 seconds at a time max., switch off for twice as long before cranking again.
Worn sprag clutch symptoms:
-- Very loud rattling when cranking
-- Starter spins but engine doesn't turn
Falure Mode:
-- Breakage
Repair:
-- Replace sprag clutch
Preventative Maintenance:
-- Maintain battery in peak condition.
-- Follow proper starting procedures. Neutral, clutch in.
Worn starter solenoid:
-- Click from under seat but no cranking.
-- Won't crank after rocking bike.
-- Starter continues to run after bike starts and won't stop until the battery is disconnected.
Failure mode:
-- Internal contact damage resulting in non-conduction.
-- Internal contact damage resulting in contacts welding shut.
-- Internal damage/wear prevents solenoid core movement.
Preventative Maintenance:
-- None.
Repair:
-- Replace starter solenoid.
Testing:
-- For no cranking, short across solenoid high-power terminals. Normal operation denotes failed solenoid contacts.
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Linear Mode
