How many times have you walked out to your motorized bike ready for a ride, only to pedal the motor and it not start? We’ve all been there, so it’s good to know what to look for to fix the problem and get you on the road. There are two typical scenerios riders see when they’re unable to start their motor, and both can be seen when you try to engage the motor:
Scenario 1:
You hold in the clutch, pedal your motor, and release the clutch. You keep pedaling and can hear the piston moving up and down in the cylinder, trying to start the motor. The bike, however, does not produce any power. What do you do?
Make sure all nuts and bolts are snug per maintenance instructions, including the cylinder head, manifold, and exhaust studs. If your studs aren’t tightened you can be allowing air leaks around your engine, which leads to a lack of compression.
Check the fuel flow in to your motor. If you are not receiving fuel into your cylinder there is nothing to combust and move the piston in the cylinder. *If you cannot get fuel in to your engine, remove the gas cap of your fuel tank. If the fuel travels into the cylinder with the cap off it is an indication that your fuel tank is not breathing- simply change the gas cap for one that allows for air flow. If the fuel does not travel to the engine, you may have a clogged fuel valve.
Check the fuel valve. The Down position means the fuel is on; sideways means it is off. Always turn the fuel valve off when not in use to avoid accidental spills or flooding your motor. Also check the filter on the fuel valve to assure it is free of debris and blockage.
Check the position of the choke. You’ll want to assure the choke is on when you’re starting your motor. Depending on the temperature in your area and the time of year, the choking time will vary. When it is warm outside you won’t need to choke the engine as long; in cold weather you’ll need to choke the motor longer.
Scenario 2:
You hold in the clutch, pedal your motor, and release the clutch. As you try to pedal the bike drags to a halt and the engine does not turn over. What do you check?
A small amount of free play is needed for your clutch cable to work properly within the clutch lever. Too much or too little free play and the bike won’t start. If you need to adjust the play slightly, you can do so on the barrel end adjuster at the clutch lever. Major cable adjustments can be done at the clutch arm with the clutch wire clip (or clutch cable stop).
Check the chain tension. An improperly adjusted chain tensioner can cause the drive chain to bind within the engine, leading to the chain snapping. Check that the engine chain is not bound around the drive sprocket inside of the engine. The play on the top of the chain should be between 1/4-1/2″ of play depending on the motor you have.
Remove the clutch plate on the right side and inspect the condition of the small and large bevel gears for wear. Also check to see if they are flush with the motor.
If everything in the clutch is in proper working order, carefully remove the cylinder head and inspect the cylinder and piston for scarring or general damage.