| Problem |
Description |
Solution |
| Engine won’t start |
Engine is unresponsive or does not crank. |
Check battery, ignition switch, starter relay, kill switch, and connections. |
| Engine cranks but won’t fire |
Engine turns over but does not start. |
Check for spark, fuel flow, clean carburetor, and verify compression. |
| No spark |
Spark plug shows no ignition. |
Test CDI unit, ignition coil, stator, spark plug, and wiring harness. |
| Weak spark |
Spark is present but faint or intermittent. |
Replace spark plug, check coil resistance, and inspect ground connections. |
| Hard to start (cold or hot) |
Requires multiple attempts or throttle input to start. |
Clean carb, adjust choke, check fuel quality, inspect air filter. |
| Engine stalls |
Engine runs briefly and dies at idle or under load. |
Clean carburetor, check idle adjustment, inspect fuel cap and vacuum lines. |
| Engine idles rough |
Inconsistent or choppy idling. |
Adjust idle speed and air/fuel mixture, clean carburetor. |
| Loss of power |
Poor throttle response or sluggish acceleration. |
Check air filter, fuel system, carb jetting, and throttle cable. |
| Backfiring |
Loud popping from exhaust or intake during deceleration or throttle use. |
Inspect exhaust for leaks, adjust carb mixture, check timing. |
| Engine overheating |
Engine gets excessively hot, possible power loss. |
Clean cooling fins, check oil level, inspect airflow paths. |
| Excessive smoke from exhaust |
White (coolant), Blue (oil), or Black (fuel-rich) smoke from exhaust. |
Diagnose and repair based on smoke color – rings, valve seals, or carb tune. |
| Fuel leak |
Dripping fuel or strong gas smell. |
Check fuel lines, carb bowl gasket, petcock, and clamps. |
| Transmission hard to shift |
Difficulty changing gears or false neutrals. |
Adjust clutch cable, inspect shifter linkage, check oil condition. |
| Clutch slipping |
Engine revs without corresponding acceleration. |
Adjust clutch cable or replace worn clutch plates and springs. |
| Grinding when shifting |
Noises when engaging gears. |
Check clutch operation, gear dogs, and shifter mechanism. |
| Battery discharges while riding |
Battery goes flat despite riding. |
Inspect stator, regulator/rectifier, and battery health. |
| Starter motor weak or dead |
Starter turns slowly or not at all. |
Check battery, solenoid, starter motor, and grounding. |
| Electrical components not working |
Lights, horn, or indicators are non-functional. |
Inspect wiring, fuses, switches, and connectors. |
| Brake fade or weak brakes |
Reduced braking power or soft lever/pedal feel. |
Bleed brakes, check fluid level, replace pads or shoes, inspect for leaks. |
| Suspension issues |
Noisy or ineffective shock absorption. |
Lubricate pivot points, inspect shocks, replace worn bushings. |
| ATV veers to one side |
Pulls left or right when riding. |
Check tire pressure, alignment, steering components, and brake drag. |
| Chain noise or wear |
Rattling, slack chain, or visible sprocket wear. |
Lubricate and tension chain, replace worn chain/sprockets. |
| Excessive vibration |
Unusual shaking during operation. |
Check engine mounts, wheels, driveshaft, and suspension components. |
