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Electrical problemsBattery dead or weak Battery overcharged ref.36 Fault Finding 1 Engine doesn't start or is difficult to start Starter motor doesn't rotate U Engine kill switch OFF. D Fuse blown. Check main fuse and starter circuit fuse (Chapter 9). □ Battery voltage low. Check and recharge battery (Chapter 9). secure. Make sure the starter relay clicks when the start button is pushed. If the relay clicks, then the fault is in the wiring or motor. ] Starter relay faulty. Check it according to the procedure in Chapter 9. Starter switch not contacting. The contacts could be wet. corroded or dirty. Disassemble and clean the switch (Chapter 9). D Wiring open or shorted. Check all wiring connections and harnesses to make sure that they are dry, tight and not corroded. Also check for broken or frayed wires that can cause a short to ground (earth) (see wiring diagram, Chapter 9). □ Ignition (main) switch defective. Check the switch according to the D Engine kill switch defective. Check for wet, dirty or corroded contacts. Clean or replace the switch as necessary (Chapter 9). D Faulty neutral, side stand or clutch switch. Check the wiring to each switch and the switch itself according to the procedures in Chapter 9. Starter motor rotates but engine does not turn over □ Starter motor clutch defective. Inspect and repair or replace I Damaged idler or starter gears. Inspect and replace the damaged parts (Chapter 2). Starter works but engine won't turn over (seized) Q Seized engine caused by one or more internally damaged components. Failure due to wear, abuse or lack of lubrication. Damage can include seized valves, followers, camshafts, pistons, crankshaft, connecting rod bearings, or transmission gears or bearings. Refer to Chapter 2 for engine disassembly. Wo fuel flow □ No fuel in tank. □ Fuel tank breather hose obstructed. [ I Fuel tap filter clogged. Remove the tap and clean the filter (see Chapter 4), D Fuel line clogged. Pull the fuel line loose and carefully blow through it. I I Float needle valve clogged. For both valves to be clogged, either a very bad batch of fuel with an unusual additive has been used, or some other foreign material has entered the tank. Many times after a machine has been stored for many months without running, the fuel turns to a varnish-like liquid and forms deposits on the inlet needle valves and jets. The carburettors should be removed and overhauled if draining the float chambers doesn't solve the problem. Engine flooded □ Float height too high. Check as described in Chapter 4. □ Float needle valve worn or stuck open (carburettor models). A piece of dirt, rust or other debris can cause the valve to seat improperly, causing excess fuel to be admitted to the float chamber. In this case, the float chamber should be cleaned and the needle valve and seat inspected. If the needle and seat are worn, then the leaking will persist and the parts should be replaced with new ones (Chapter 4). □ Starting technique incorrect. Under normal circumstances (i.e., if all the carburettor functions are sound) the machine should start with little or no throttle. When the engine is cold, the choke should be operated and the engine started without opening the throttle. When the engine is at operating temperature, only a very slight amount of throttle should be necessary. Wo spark or weak spark □ Ignition switch OFF. U Engine kill switch turned to the OFF position. D Battery voltage low. Check and recharge the battery as necessary (Chapter 9). □ Spark plugs dirty, defective or worn out. Locate reason for fouled Spark plug caps or secondary (HT) wiring faulty. Check condition. Replace either or both components if cracks or deterioration are evident (Chapter 5). D Spark plug caps not making good contact. Make sure that the plug caps fit snugly over the plug ends. Zl Ignition control unit defective. Check the unit, referring to Chapter 5 for details. □ Pulse generator defective. Check the unit, referring to Chapter 5 □ Ignition HT coils defective. Check the coils, referring to Chapter 5. corrosion, damage or excessive wear. The switches can be disassembled and cleaned with electrical contact cleaner. If cleaning does not help, replace the switches (Chapter 9). □ Wiring shorted or broken between: a) Ignition (main) switch and engine kill switch (or blown fuse) b) Ignition control unit and engine kill switch c) Ignition control unit and ignition HT coils d) Ignition HT coils and spark plugs e) Ignition control unit and pulse generator □ Make sure that all wiring connections are clean, dry and tight. Compression low C Spark plugs loose. Remove the plugs and inspect their threads. Reinstall and tighten to the specified torque (Chapter 1). □ Cylinder head not sufficiently tightened down. If the cylinder head is suspected of being loose, then there's a chance that the gasket or head is damaged if the problem has persisted for any length of time. The head bolts should be tightened to the proper torque in the correct sequence (Chapter 2). □ Improper valve clearance. This means that the valve is not closing completely and compression pressure is leaking past the valve. Check and adjust the valve clearances (Chapter 1). I Cylinder and/or piston worn. Excessive wear will cause compression pressure to leak past the rings. This is usually accompanied by worn rings as well. A top-end overhaul is necessary (Chapter 2). □ Piston rings worn, weak, broken, or sticking. Broken or sticking (Chapter 2). D Piston ring-to-groove clearance excessive. This is caused by excessive wear of the piston ring lands. Piston replacement is necessary (Chapter 2). □ Cylinder head gasket damaged. If a head is allowed to become loose, or if excessive carbon build-up on the piston crown and combustion chamber causes extremely high compression, the head gasket may leak. Retorquing the head is not always sufficient to restore the seal, so gasket replacement is necessary (Chapter 2). □ Cylinder head warped. This is caused by overheating or improperly tightened head bolts. Machine shop resurfacing or head replacement is necessary (Chapter 2). [ Valve spring broken or weak. Caused by component failure or wear; the springs must be replaced (Chapter 2). Fault Finding ref.3? 1 Engine doesn't start or is difficult to start (continued) Date: 2016-01-14; view: 785
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