This post was Last updated on : 01/30/2020
Before “starting”, make sure you are not ignoring most basic things. Because sometimes we forget simple things.
- New Fuel is available in tank & holding left brake lever while pressing start switch.
- Engine oil – No engine oil(even a small leak will drain whole engine oil in a period of few months), oil filled more than needed, less oil, dark brown or black colored engine oil etc are common reasons of trouble in starting.
Ultimate step by step guide to troubleshoot and repair a motor scooter/bike that won’t start.
When kick starting, if you only hear sound of mechanical parts moving, it means No ignition is there. Sound of mechanical parts moving only means there is no explosion sound.
Scooter not starting and no sign of ignition is normal in cold whether.
- Case 1 – Only mechanical parts moving sound(with compression). This sound will be similar to when we try to kick without turning on the key. Engine crankshaft & other parts are moving, but no ignition.
- Case 2 – One or two powerstroke sound and stopping. This sound can be identified as Deep “Teih, Teih” sound.
- Case 3 – No compression. In this case, there is no ignition or compression. In this case kicker will be loose, and there will be no compression. Means air pressure is loosing through some leaks. For example we take spark plugs out of engine & turn motor over there will be no compression.
Case 1 – Sound Sample – No ignition while kick starting.
Case 2 – Sound sample – Engine starts but suddenly shuts off.
It is a little bit difficult to differentiate this sound when starting with a starter motor. But even with starter motor sound, explosive sound of engine starting can be easily identified.
Scooter not starting – troubleshooting step by step
First 3 things what mechanics check when a motor scooter is not starting are Fuel, Engine oil & spark(Spark plug).
Case 1- No ignition while kick starting.
- Step 1 – Common reason for ignition system not working is spark plug. So remove spark plug from engine & inspect it.
- Step 2 – If spark plug is in good condition, check battery. If brake light is not turning on, battery is dead. While some scooters will start and run even without a battery, some ignition system will not work without a battery. If this is the case, try jump starting it.
- Step 3 – Ignition coil in another important part of ignition system. Ignition coil is what provide very high voltage to spark plug.
- Step 4 – CDI unit is the brain of ignition system in most low end motor scooters. There is 2 types of CDI systems, AC cdi & DC cdi.
- Step 5 – Regulator & rectifier is another part part of ignition system in scooters, but these parts rarely get defective.
- Step 6 – Check for Starter relay problems.
- Step 7 – Magnetic coil in engine, create current for charging battery and also for lights.
Case 2 – Engine starts but suddenly shuts off.
This is better than case one, because in this case engine is woking. Engine will shut off because of many reasons. Following are some step by step guide to figure out its problem.
- Step 1 – In this case also, remove spark plug from engine and inspect it. Make sure that spark is white in color, It is hitting at the center of spark plug center electrode. Clean or replace it.
- Step 2 – Make sure engine oil is in good condition & right amount. It should not be too dark in color.
- Step 3 – Clean and tune carburetor, dirty or clogged carburetor is one of the main reasons of this problem.
- Step 4 – Recharge or replace battery if dead. Try to jump start it with other battery.
- Step 5 – Make sure engine compression is there.
- Step 6 – Clean & replace air filter.
- Step 7 – Check for Engine spark timing(this will also cause compression loss)problems (Very low chance of this happening).
Case 3 – No Compression from scooter/bike engine
Loss of compression from engine can happen because of leak in valves, broken parts, defective engine head gasket, problem with timing belt etc. Or there is a hole in piston.
- Step 1 – Do a compression test. If sure about no compression avoid this step.
- Step 2 – No compression is a major problem with engine(Kind of). So if you are trying to repair it by yourself, open engine head & check for issues. This can be done without removing engine completely.