| Problem |
Description |
Solution |
| Engine won’t start |
No crank, click, or ignition response. |
Check battery charge, starter relay, ignition switch, kill switch, and fuses. |
| Engine cranks but won’t fire |
Starter turns engine but it won’t start. |
Check for spark, fuel flow, carburetor condition, and compression. |
| No spark |
Spark plug not firing during ignition. |
Test CDI, stator, ignition coil, spark plug, and all electrical connections. |
| Weak or intermittent spark |
Spark is weak or cuts in and out. |
Replace spark plug, inspect ignition coil and wires, ensure good ground. |
| Hard to start (cold or hot) |
Difficult to start unless throttle or choke is manipulated. |
Clean carburetor, check choke/enricher circuit, inspect air filter and fuel. |
| Engine stalls after starting |
Engine runs briefly then shuts off. |
Check fuel flow, clean idle circuit, adjust idle screw and mixture. |
| Unstable idle |
Idling is rough, surges, or dies without throttle input. |
Adjust idle speed, clean carburetor, inspect vacuum lines. |
| Loss of power |
Sluggish acceleration or poor top-end performance. |
Clean air filter, inspect throttle cable, clean carburetor, check jetting. |
| Backfiring |
Loud popping from intake or exhaust, especially when decelerating. |
Check air leaks, timing, adjust air/fuel mix, inspect exhaust for leaks. |
| Overheating |
Engine runs very hot, may shut off or lose power. |
Clean cooling fins, check oil level, inspect cooling fan and sensor (if equipped). |
| Excessive exhaust smoke |
Blue (oil burn), black (rich fuel), or white (coolant or steam). |
Blue: Valve seals/rings. Black: Rich mixture. White: Check head gasket. |
| Transmission won’t shift properly |
Gears don’t engage or shift smoothly. |
Check shift linkage, clutch adjustment, and inspect transmission fluid. |
| Clutch slipping |
Engine revs but doesn’t transfer power well to wheels. |
Adjust clutch or replace worn clutch plates/springs. |
| Grinding while shifting |
Grinding noise when shifting gears. |
Inspect shift drum, forks, clutch operation, and check transmission oil. |
| Battery not charging |
Battery loses charge even while riding. |
Test stator, regulator/rectifier, and connections. |
| Starter motor won’t turn |
Starter doesn’t engage or turns very slowly. |
Check battery voltage, solenoid, starter motor, and grounds. |
| Lights or electronics not working |
Headlights, tail lights, or dash are dead. |
Inspect bulbs, fuses, wiring harness, and handlebar switches. |
| 4WD not engaging (if equipped) |
4-wheel drive won’t activate when switch is pressed. |
Check 4WD actuator, switch, wiring, and front differential. |
| Fuel leak |
Gasoline smell or dripping fuel near carb/tank. |
Inspect fuel lines, carb bowl gasket, petcock, and tighten all connections. |
| Weak or spongy brakes |
Brakes feel soft or require more pressure to stop. |
Bleed brakes, check brake fluid level, inspect pads/shoes and hoses. |
| Suspension issues |
Bouncy, stiff, or noisy ride over rough terrain. |
Check and replace shocks, grease bushings, inspect swingarm bearings. |
| Excessive vibration or rattling |
Abnormal shaking or noise while riding. |
Inspect engine mounts, driveshaft, skid plates, and loose bolts. |
| ATV pulls to one side |
ATV veers left or right when riding or braking. |
Check tire pressure, brake drag, steering alignment, and suspension damage. |
| Drive belt slipping (if equipped) |
Engine revs but ATV doesn’t accelerate properly. |
Inspect and replace worn belt, check clutch sheaves and alignment. |
