Trident 750 - Unable To Start

When you say the battery is "fine" it has to be tip top or, if the battery is even slightly below voltage it wont even try to start. it needs 12. something volts. to throw the starter.
" it would just go fail to turn over" Again battery or possibly connections.

Starting System Symptoms:

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:

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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Please free to comment, make suggestions, etc.

Jim
(Stolen and kept safe)

 

Make sure your Battery is fully charged or you could damage the sprag clutch, possibly jump from a car battery, if its on the car leave the car switched off !!
There are apparently some duff spark plugs about so be careful where you buy from ...
Do you have a good spark ?
Are the plugs wet ?
Have you trapped / kinked the vac hose or fuel hoses when replacing the tank ?
Have you tried using the prime position ?

 

If it will start when jump starting from a car battery (or similar) and restart on a regular basis then the battery is no good. Wemoto have an offer on Motobatts at the moment (around £45 ish) and Dynavolts (similar spec) are available for a similar quantity of your £s somewhere on ebay apparently.

 

I would check valve clearances (mainly inlets close up)
then check piot jets are clear
Battery Yuasa YTX14AHL-BS

 

Lots of advice above. Mine would be ‘Take a deep breath, think’.

What state is the bike in and what has changed? Specifically, how old is the fuel in the tank? Was it just static running or on the road? Is the engine modified in any way?

If the plugs are sooty you may simply have a rich mixture (running on choke?) leading to a weak spark. With older fuel the most volatile elements will have evaporated off. They are the particles that ignite most readily.

I would be for fully charging the battery/jumping off a car battery (engine off) having cleaned the plugs and, if necessary, put new fuel in. Check for a spark and, if present, turn her over.

If there is no spark launch into your ignition system but that is a less likely scenario than a cold, damp garage, old fuel, old wiring and a general reluctance to get out of bed!