Mini Bike Troubleshooting

A guide to mini bike troubleshooting

Engine will not start

  • Check if there is gas and oil in the tank
  • The kill switch is turned off
  • The engine choke is not at the proper position
  • Wiring of spark plug is disconnected
  • Check the air filter (should be cleaned regularly)
  • Throttle cable is grounded to engine
  • Start switch or battery is dead if using electric start units
  • Stale fuel ( fuel that has gone bad more than 60 days)

Bike Turns off after some time

  • Check if the gas contains water or not. If water is present as soon as it reaches the carburetor it will switch off. Check this by looking at the bottom of the gas tank if there is any “beading” of water present. Remove the water by draining the tank.
  • The spark plug wire is loose or has gone bad
  • The air filter is wet or clogged
  • The stop switch is broken
  • The throttling cable is being grounded
  • Malfunctioning carburettor

Not powering up or throttle is not going back to idle

  • Adjust the throttle cable properly
  • Lubricate the throttle link
  • Overtightened throttle linkage
  • The pedal and throttle return spring has either been stretched or broken
  • Engine throttle linkage is binding


Stop and start switches

Start switch does not operate

  • Check the connections and the voltage of the battery
  • Inspect the connectors for the start switch
  • The start switch is broken
  • Solenoid is faulty

Stop switch does not operate

  • The ground wire is loose
  • The wire is either not connected properly or broken
  • The engine terminal is loose
  • Malfunctioning toggle switch and engine ground terminal


Electrical Systems

Headlights are not working

  • Burnt out head lights
  • Broken or disconnected wiring
  • The battery voltage is low
  • Grounding is poor


Drive System

Centrifugal Clutch System

Bike moving while on idle

  • Worn out and overheated clutch caused by no lubrication
  • The tension is driving chain is too tight
  • High adjustment in engine idle


Torque Converter System

Bike moving while idle

  • Belt is assembled in the wrong orientation
  • Incorrect belt type- incorrect length will cause the bike to creep at idle
  • The driving clutch on the crankshaft is not working properly
  • The driven pulley on the jackshaft is not working properly
  • Spacing in the driving pulley is not correct
  • Engine idle is set at above recommended
  • Misalignment in pulley will destroy belt
  • Poor, slow or jerky acceleration
  • Drive system is not working properly
  • The throttle cable is not adjusted properly
  • The drive chain is loose or worn due to absent of lubrication
  • Brake is dragging and binding on axle or bearings
  • Malfunctioning engine

Low speed

  • The throttle cable is not adjusted properly
  • Dragging of brakes or bearing on axle
  • Drive system is not working properly
  • Tire pressure is not at proper pressure
  • Malfunctioning engine


Drive Chain

Chain Is not engaging on sprocket

Chain tension
Chain Tension Check
  • Not enough chain tension
  • Worn or stretched chain
  • Misalignment of sprockets
  • Sprocket is bent or worn or loose from sprocket hub
  • Drive wheel is loose
  • Bent axle
  • Frame is bent


Brake Systems

Lining wears Quickly

  • Brake rod and cables not adjusted properly
  • Using of the brake too much


Brake doesn’t work

disc brake mini bike
Mini bike Disc brake
  • Brake rod and cable is not adjusted properly
  • The brake pad is worn
  • Missing key in the brake disc
  • Missing key in the wheel hub


Brake wont release

  • The brake rod is not adjusted correctly
  • The brake linkage is unlubricated
  • The brake linkage is too tight
  • Stretched or broken brake return spring



Hard to steer

  • The joints and linkage is unlubricated
  • Spindle pivot bolt is fastened too tight
  • The tire pressure is not at recommended level
  • The Toe-in is not adjusted properly
  • The tie rod end is binding
  • The spindle or tie rod is bent
  • The front axle is bent
  • The steering column is bent


Erratic engagement

The motorist clutch that’s mounted on the engine crankshaft frequently causes unpredictable engagement. Understanding how they work may help you discover why yours does not.

As engine rpm falls, the pulley driving the belt to a greater circumference is closed by the spring in the driven pulley. This activity causes the driver clutch pulley to open, letting the belt to go a lesser circumference round the motorist clutch and defeats the power of the flyweights against the movable sheave. The sides of the belt must not engage when the engine is at idle. The belt ought to not be tight in resting and the pulley on the bronze bushing round the hub. The movable sheave has to have the ability to slip without binding on the splined hub. Disassemble the motorist clutch and clean away any lubricant or soil deposit using an automotive parts. Don’t make use of an oil based lubricant between the hub and movable sheave or in the motorist clutch. Make use of a dry, molybdenum established lubricant. The extreme heat and pressure within the motorist clutch chars oil based lubricants. Filth which causes increased wear additionally gathers. Oil lube is not preferable to graphite lube, but nonetheless, it also finally makes a residue that builds up on the parts, making them bind and need more regular cleaning.

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