Hi, John and the usual suspects are:
1. Fuel tank empty.
2. The fuel tank has old dead gas.
3. Fuel tank bottom contaminated with ethanol sludge, dirt, water, rust, etc.
4. Fuel supply valve/petcock turned off.
5. Fouled spark plugs.
6. Engine flooded as a result of overuse of the choke.
7. Vacuum hose to the fuel supply valve/petcock disconnected, broken, cracked, or pinched.
8. Fuel valve/petcock or filter clogged.
9. Fuel line to carburetor or throttle body pinched, kinked or blocked.
10. Carburetor float stuck.
11. Fuel injectors clogged.
12. Fuel injectors stuck open.
13. Quick disconnect check ball stuck.
14. Compression below 75 PSI.
15. A stuck-bent-burnt valve.
16. Severely discharged or a damaged battery should have 12.5 volts or more and be able to pass a proper "LOAD" test if necessary, you may have a cursory reading of 12.5 volts or more but little or zero amperage the battery is faulty and must be replaced, AGM batteries fail in this scenario more so than lead-acid batteries.
17. Check battery terminals for damage or corrosion, check the battery cables at "BOTH" ends for loose, corroded, or broken connectors, "INSIDE" and outside the cable harness, perform connector wiggle test and check cables with an ohmmeter if necessary.
18. Loose or corroded wire connection at the coil or plug between ignition sensor and ECM module.
19. Spark plug cables in bad condition and shorting check for spark leakage in the dark, cable connections are loose or connected to the wrong cylinders.
20. Ignition timing incorrect due to a faulty ignition coil, ignition module or MAP, CMP, CKP, O2, TPS, ETP, IAC sensors.
21. Faulty neutral, clutch, kickstand safety switch.
22. Faulty fuel pump or fuse or relay.
23. Faulty or corroded run/stop switch.
24. Tilt sensor needs a reset.
25. Security system not disarming alarm needs a reset.
26. Check for engine trouble codes.
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Hi, Dean before testing any electrical component in the Starting Circuit it is "IMPERATIVE" that you have a fully charged battery of 12.5 volts or more and be able to pass a proper "LOAD" test if necessary, you may have a preliminary reading of 12.5 volts or more but little or zero amperage, the battery is faulty and must be replaced. AGM type batteries fall into this scenario more so than lead-acid batteries.
1. Ignition Switch not in the "ON" position.
2. Engine Run Switch in the "OFF" position.
3. Engine Run Switch is "FAULTY" or corroded.
4. Check the battery terminals for damage or corrosion check the battery cables at "BOTH" ends for loose, corroded, or broken connectors, "INSIDE" and outside the cable harness, perform connector wiggle test and check cables with an ohmmeter.
5. Bank angle sensor needs a reset or is faulty.
6. FOB battery low or dead.
7. Faulty ignition switch.
8. Faulty starter button.
9. Faulty kickstand, clutch, neutral safety switch.
10. Security alarm needs a reset.
11. Starter relay, solenoid, starter motor or circuit wiring faulty.
12. Starter armature or field coils have failed.
13. Main fuse or circuit breaker may be blown or faulty.
14. Faulty ignition relay.
15. The electric starter is working but starter clutch has failed.
16. Check for engine trouble codes.
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Hi, Pete you may have squeaked your top end this is commonly known as "HEAT SEIZE" the piston heats up expands and becomes extremely tight in the cylinder bore and usually occurs mainly on 2 cycle engines right after a fresh top end rebuild, but it can also happen to brand new motorcycles, these are rare instances due to better quality control and education. Overheating failures that cause pistons to seize are many and each one should be carefully diagnosed to prevent future repeat offenders and the usual suspects are:
1. Lack of lubrication due to low or no oil.
2. Among the causes of lack of cylinder, lubrication is clogging of lubricator by dirt or waste, obstruction in oil pipes/lines, leaky check valves, leaky pump packing, broken oil pipe/line, oil too cold to feed.
3. Wrong type of oil used in premix or oil tank.
4. Improper premix ratio you should start with 32:1 as a baseline.
5. New rebuild piston to cylinder tolerances set up too tight.
6. Failure to follow proper break-in procedures with a 16:1 premix ratio.
7. Loose fasteners causing intake, base, or head gaskets to leak or blown crankshaft seal, failure caused by age, overheating or walking.
8. Holes in the intake manifold bent or warped intake flange or reed cage any stray air coming into a cylinder will cause a super lean condition.
9. Improper assembly of reed valve gaskets.
10. Insufficient warm-up time for temperature conditions before WOT.
11. Broken, pinched or cracked fuel line.
12. Carburetor fuel passages clogged or restricted from stale fuel varnish, ethanol sludge, dirt, rust, or fuel level in float bowl too low.
13. Main jet size too small or partially clogged
14. Air filter improperly installed, missing or not sealing.
15. Faulty or improperly adjusted oil pump and or cable.
16. Failure to bleed oil pump after a rebuild/replacement or running oil tank dry.
17. Engine coolant level too low, too old, or improper mixture ratio.
18. Radiator clogged, fins damaged, or faulty cap.
19. No liquid circulation due to failed oil or water pump.
20. Cavitation due to air in oil or coolant system.
21. Water and oil mix due to a blown head gasket.
22. Timing retarded due to faulty CKP sensor or CDI.
23. Improper spark plug heat range (too hot) and or gap.
24. Excessive engine load, brakes dragging, clutch slipping, transmission lubricant level too low or viscosity to high.
For more information about your issue and valuable "FREE" downloads that you will need for viewing or printing please click on the blue links below. Good luck and have a wonderful day. Kymco ZX50 SC10 motor build AF16 clone 49ccScoot com Scooter Forums 50cc KICKSTARTER PROBLEMS AND SOLUTIONS KYMCO ZX Service Manual Fever 1 50 ZX50 KCA SA10AL Kymco Scooter Parts Racing Planet USA KYMCO ZX 50 User Manual