Coil testing

[Laava]

Is it easy enough to test coils yourself or does it really need to be done at a shop with proper testing machine?

[unstuck]

Best test you could do at home would be a swap of units. Dynamic or continuity test is about all you could do at home I would think.

[Brian d marge]

I have an old coil testing unit ...somewhere , but its easier just to mahe one your self , all you do is increase the spark gap untill it fails , ( 7mm? too long ago sorry )

then as u test them gheat them up with a hair drier , ..

the cost of the things , just bin em and fling a new set on ,

Stephen

[nodrog:Me]

Just hold the lead in your teeth and crank it over.

[Laava]

Just hold the lead in your teeth and crank it over.

Thanks for that! Now I have smashed teeth, a black hole in my tongue and I sharted! Thanks a lot!!

[Laava]

Actually, I took it to an auto sparky and put it on the machine. I have huge sparks jumping approx 15-20mm! Plus I didn't shart!

However when checking with ohmeter, 1 coil has nearly 40,000ohm resistance on secondaries as per spec and the other has infinity. Does that mean it is fucked?

[spanner spinner]

Actually, I took it to an auto sparky and put it on the machine. I have huge sparks jumping approx 15-20mm! Plus I didn't shart!

However when checking with ohmeter, 1 coil has nearly 40,000ohm resistance on secondaries as per spec and the other has infinity. Does that mean it is fucked?

yep the one with infinity is landfill, if the electrons from your mulitmeter can't get through the electrons making the sparts can't get through either.

[Laava]

Thanks SS, I was actually hoping to find a good reason for the crap running of my bike and this appears to be it BUT when it was on the coil testing machine earlier it appeared to be OK? I will ring my mate and see if there is an explanation for that.
Any chance that it would spark well at highish revs and then fail at idling speeds?

[spanner spinner]

if the lead connection intenaly in the coil body has burnt away the voltage will still jump this gap just like jumping the plug gap in perfect conditions. But it will keep burning away untill it fails complety. Hopefull this will explaine why it worked some times and not at other times.

[Laava]

That makes sense. Thanks mate.

[Laava]

Does anyone know if these coils[twin HT lead] have seperate windings for each lead or are they both just hooked straight up to the same winding? Only that now I have pulled the plugs, one of them is still like new and has obviously not had any spark whereas it's coil mate has been working and is all sooty like