Time for some sanity checks
The various electrical systems on your bike may all be interlinked but just because one part works doesn’t mean everything will function as it should.
Before the ‘Big StartUp’ check that the front and rear lights, brake lights, indicators and panel lights all work and if they don’t, suss out why. A couple of crossed over wires here may, just may, cause issues when the engine is running. If fuses are blowing it’s a sure sign something is definitely wrong. At this stage you really will need all the peripherals properly sorted before you go any further.
If the electrics are okay, double check the HT (High Tension) system for reliable sparks. Little is more frustrating than trying to get a bike to fire up if there’s no spark at the plugs! With the spark plugs out of the bike, ensure they are fully and permanently earthed before proceeding; electronic/CDI systems can be seriously damaged if the plugs are fired but not earthed. With the fuel off, turn the engine over with the ignition switched to ON and turn the engine over; you should be able to see a decent spark in daylight.
If there’s no spark look for a reason. If there’s a big fat spark we can move on. Double check you’ve added engine oil. With two-strokes, the tank, the lines, the pump and the supply to the carbs/inlets/cylinders needs to be free of air. If not, one or more pistons may be starved of oil.
With four-strokes it’s a good idea to get the oil pumped around everything before the engine fires. Most engine wear occurs when an engine is cold and on a cold, new, engine with minimal oil present things get hot and wear really fast. If your kill switch only cuts the ignition circuit and not the starter motor you can turn the engine over in short bursts with the plugs out. If it’s a kick start only motor, snick the engine into a highish gear and wheel the bike around for few minutes to circulate the oil.
We’re almost there now but there’s one more key check needed. Turn the fuel on and wait several minutes then carefully look for leaks. You really don’t want fuel leaking anywhere and especially not over any freshly painted engine surfaces. Petrol running out of the carburettor overflow normally signifies a stuck float; gently tap the float bowl with a small hammer or screwdriver handle and see if it stops. If it does, great. If not, examine that carburettor in more detail. If your bike runs a vacuum tap it’s much harder to check for leaks as the engine needs to be working in order to generate a vacuum which activates the tap. Under these circumstances you’ll need your wits about you.
So here goes, let’s see if it runs. Fuel on, ignition on, kill switch to RUN, and choke on. If everything’s as it should be the engine should soar into life but this is rarely the case. The carburettors may not be full so the engine may struggle; avoid opening the throttle as this may flood the engine. A half-hearted cough from an engine is a good thing; next time try to ‘catch’ it on the throttle. With kick start motors it’s surprising just how much effort it can take to get the engine alive but with patience and bit of luck it will happen.
Once the engine catches, hold it on a gentle throttle and allow it to warm up checking for oil, petrol and water leaks all the time. Once there’s some heat in the cylinders the motor should run on its own but if it dies check and reset the tickover. Now hold your hand over, not on, each downpipe in turn and see if they’re all getting equally hot. If they aren’t it’s either ignition or fuel that’s causing a problem. With the engine now up near operating temperature you can treat yourself to a few tweaks of the throttle and enjoy the fruits of your labours… well done.
Now turn the engine off and allow it to cool down then repeat; everything has had one heat cycle so it should all have settled down a bit. Check once more for leaks, double check oil levels and fire the motor up again. At this point it’s worth running a multimeter across the battery to check it’s charging properly; your manual should give figures but with the engine running expect 13.8-14.5V if you have a modern AGM battery.
NEXT TIME First ride and what needs looking at.