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.

Motorcycle Monthly - - The Inside Line To Classic Japanese Iron With Stev - Words: Steve Cooper Photo: Gary Chap­man

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.

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