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power at coils but no spark
Posted: Thu Jan 05, 2012 7:09 pm
by ross46
once again another electrical problem, after fixing the broken permanent live the bike started and ran lovely, now iv gone back to try and start it and it wont go, put the battery on a trickle charge overnight till fully charged, checked for a spark by grounding the spark plugs on the top of the engine, none of them would spark, removed the caps and tried the ht leads, still nothing, so thought it could be the coils although i thought to be unlikely that both would have gone, using a test light i checked there was power at both the red wires and there was, connected them to both coils and checked the other wires, one was green one was black and there was power there, tried testing the coils by putting some wire in where the ht leads go and testing on the head and with the test light, nothing, any help would be greatly appreciated, thank you in advance, ross
Re: power at coils but no spark
Posted: Thu Jan 05, 2012 9:40 pm
by RedexRobB
Have u checked the pickup coil?
Re: power at coils but no spark
Posted: Fri Jan 06, 2012 1:11 pm
by Tirpitz
Not sure exactly what you mean when you say you've tested with wire in the coils where the HT leads would go. The coil output won't produce a voltage unless there is a voltage CHANGE across the input. Stead voltage will produce nothing. The coils are a transformer so only produce an induced output voltage when the input voltage changes.
The output is a high voltage which will break down the insulation on ordinary wire so I'm not sure that you can test in the way you are doing. For what a metre of HT lead costs from a spares shop (couple of quid) you might as well buy some and test the output properly rather than fiddling round with wire.
If you're getting nothing out of the coils you need to check you have a FLUCTUATING voltage across the input. I'm not sure a test lamp will show you this as the filament won't flicker visibly enough. You want a voltmeter - they're cheap enough. Then you can see what's being produced as you crank the motor. If the voltage is steady you're not going to induce a spark in the coils, so as Rob says you need to be looking then at the pickup.
TBH I find it odd that the bike ran fine then doesn't with nothing else being touched. I'd be looking at the battery. Doesn't matter that there's enough to spin the motor, ZXRs need a tip-top battery to fire.
Re: power at coils but no spark
Posted: Sat Jan 07, 2012 3:34 pm
by ross46
right bought a voltmeter, touched the wires to the head and the red wires and there didnt seem to be a fluctuating voltage as i cranked it, it didnt show any voltage on the voltmeter? i had it on dc, wondered if it needed to be ac as its fluctuating? does this mean i have to look at the pick up coil? if so where is it? as i looked at the manual and it wasnt very obvious where in the engine it was?
Re: power at coils but no spark
Posted: Mon Jan 16, 2012 10:55 am
by ross46
ok have managed to get 12 volts at the red lives to the coils, but i tried to start it the other day and it cranked then just stopped and started to whir and click. the clicking is coming from the fusebox and have checked and found the solenoid is shagged. my problem now is that if i bridge the solenoid the engine doesn't crank, the starter motor whirrs? im not sure what the problem is? is it the starter motor or something else? i really hate these electrical problems as i want to get it running ready for my test, many thanks
Re: power at coils but no spark
Posted: Thu Jan 19, 2012 7:50 pm
by RedexRobB
Sounds like a flat battery if its just clicking away when you push the starter button.