Major mechanical failures are rare, so when your bike engine cuts out or fails to start it’s easy to fear the worst. There are a few things that cause mechanical failure.
Making sure your machine is regularly serviced and checked over by a professional mechanic will prevent most problems. But when the engine stops and you’re stuck by the side of the road it’s worth trying a few things to get you home under your own steam, rather than on a tow truck. If you do get it going, take it to a professional to make sure all is well.
Engine won’t start or stops
Let’s just check that kill switch on the right handlebar before we go any further. Usually it will cut off all power to the engine so it won’t even turn over. Other traps include having the side stand down or not pulling the clutch in to start. If all these check out, investigate:
Check for sparking issues:
- Remove a spark plug, put the cap back on it, then make sure the metal collar touches the engine block to earth it
- Make sure there’s no fuel or vapour around, and never touch the plug or cap with the ignition on. Switch the ignition on and turn the engine over. If there’s no spark, track the leads back to the coil, look for cracks and secure connections. Also, check the battery leads are tight.
- Make sure you haven’t run out of petrol
- Check you haven’t turned off the fuel tap if the bike has one.
- Check for a blockage. With carburettors, wait for the engine and exhausts to cool down then loosen the drain screw on the float bowl. If fuel flows, then it’s probably not a blockage.
- Check the throttle cable moves the slides inside the carburettor and the mechanism is not detached the float bowl is empty, work back over the fuel lines to the tank to find the blockage. It could even be a clogged filter inside the tank.
With fuel injection, roadside checking is pretty much limited to checking the throttle is actuating the levers on the throttle bodies. For this, and checking many carburettors, you’ll need to remove the petrol tank.
Be careful not to spill petrol. Pinch the line or close the end with tape or a suitable screw.
Bike engine seizure
It’s rare for a four-stroke engine to seize but it can result from working a new engine too hard or running low on oil.
On two-strokes, seizures can be caused by overheating, the wrong fuel/oil ratio or a malfunctioning oil pump. If you feel an engine is dragging and about to seize, whip in the clutch until you’ve stopped.
A partial seizure may free up once the engine cools. If not, call for help.
View towing as a last resort. You can only be towed by another motorcycle and both riders must have a full licence. Maximum speed when towing is just 30km/h.