A no-start is the job most likely to be solved by replacing parts until it goes. It is also the job that responds best to a fixed sequence, because an engine needs only three things and they can be tested separately: fuel, spark and compression. Work through them in order and the fault is usually found before anything has been bought.
Start with the free checks. Fuel in the tank and the tap open or the pump priming. The kill switch off and the side stand up, because both interlocks fail closed and both are routinely overlooked. The clutch lever pulled if the vehicle requires it. The battery terminals clean and tight. The main fuse intact. It is worth being unhurried about this list - a meaningful share of no-start jobs end here, and every one of them ends without a part.
Distinguish the three no-start behaviours. They point in completely different directions. If nothing happens at all, or you get a single click, the problem is electrical supply - battery, terminals, earths, starter relay. If it cranks normally but does not fire, it is fuel or spark. If it cranks unusually fast and lightly, with none of the usual resistance, suspect compression. Naming which of the three you have narrows the job immediately.
Test for spark properly. Remove the plug, reconnect the cap, earth the plug body firmly against bare metal on the engine - not against paint - and crank. A healthy spark is a fat blue snap that you can hear. A thin yellow one that only appears intermittently counts as no spark for diagnostic purposes. If there is no spark, work back through the plug, the cap and lead, the ignition coil, the CDI or ECU, the pickup or pulser coil, the kill switch and the side-stand switch, and the earths. Do not condemn the CDI first because it is the part everyone suspects; it is a common failure but it is not the most common one.
Read the plug while it is out. It tells you what has been happening. Dry and clean, and fuel is not arriving. Wet with petrol, and fuel is arriving but not igniting, or the engine has been flooded by repeated starting attempts. Black and sooty means running rich, and the air filter is the first thing to look at. Oily suggests oil reaching the combustion chamber. White and glazed suggests running lean or too hot a plug.
Check fuel delivery. On a carburettor machine, look for fuel actually reaching the float bowl - a blocked tap filter, a clogged inline filter, a stuck float needle or a blocked pilot jet are all common, and a bike that sat unused through a monsoon will usually have varnish in the pilot circuit. On a fuel-injected machine, listen for the pump priming when the ignition is switched on and check its fuse and relay before anything else.
Check compression last, because it is the expensive answer. A compression test with the throttle held open gives a number to compare against specification, and against the other cylinder if there is one. Low compression on a two-wheeler is usually rings and bore, a valve not seating, or valve clearances that have closed up over time. Valve clearances are worth checking before condemning anything, especially on an engine that has never had them set - a tight exhaust valve holds itself open, kills compression and burns the seat if it is left.
The seasonal no-start. Mumbai produces two of these reliably. A bike that stood through the monsoon has a varnished carburettor and a sulphated battery, and both need attention rather than one. A bike that stopped in flood water may have water in the cylinder, and cranking it is how a small job becomes an engine rebuild - remove the plug and turn the engine over by hand before any starting attempt.
What we hold for these jobs. NGK and Champion spark plugs, Spark Minda and Varroc ignition components including CDI units and coils, UCAL carburettors and overhaul parts, Lumax and Uno Minda filters, and Goetze piston and ring sets where compression turns out to be the answer.
Send the part code or the model and the symptom, and we will confirm stock the same working day.
Confirm spark first by earthing the removed plug against the engine and cranking; a fat blue spark is healthy. If spark is good, check that fuel is reaching the float bowl or that the fuel pump primes. Check compression only after those two, because it is the expensive answer.
Not first. Check the plug, cap and lead, the coil, the pickup coil, the kill switch and side-stand switch, and the earth points before the CDI. CDI units do fail, but they are replaced unnecessarily far more often than they actually fail.
We stock it. Send the part code for same-working-day confirmation.
