increasing spark plug gap

[DirtyErnie]

You're right about the larger gap and high RPM. A larger gap requires more voltage, which limits the current and dwell time of the spark. Current and dwell is what really starts the fire. You're trying to balance that against increasing the amount of exposed fuel/air charge in the longer gap. Eventually you will hit a point where there isn't enough energy in the spark event to get reliable ignition.
I still haven't found that point at .050", but I sure don't see much need in opening the gap any bigger.

 

[ReycleBill]

Old thread with lots of great info. I think I'll widen my plug gap slightly and see how it works out.

By the way, check out these 2 videos and see if you can tell me what is going on here.

and this one

 

[Jack]

Hot Wire ignition cables also used a capacitor to increases spark, you don't hear much about them,cost was a big factor vs actual gains.
https://www.nology.com/hot.html

 

[ReycleBill]

Hot Wire ignition cables also used a capacitor to increases spark, you don't hear much about them,cost was a big factor vs actual gains.
https://www.nology.com/hot.html

$72 for 2 plug wires. Looks like they are really proud of those wires and a mite bit steep for this tarheel boy.

 

[gggGary]

IIRC with pamco and a good coil Pete suggested about .035" as a reasonable gap. Anyways that's a goto gap for me with Accel coils. shrug.

 

[5twins]

For a dual output coil and electronic ignition, I go with a .032" plug gap. For the wimpy stock dual coils and points ignition, I stick to the recommended .028" factory gap spec.

A local guy called me one time because his 650 wouldn't start. He had just installed brand new plugs. I went over to have a look. I checked the gaps on his new plugs first thing. He hadn't checked or adjusted them from the way they came. NGK had them gapped very big, like in the 40's. I re-set the gaps to the recommended .028" (he had a stock points ignition and coils) and the bike started right up.

 

[Bushyeyed1]

I know this is a subject on gap but I just bought new ngk plugs and did a resistance reading of electrode on one is near zero or 0.03 ohms and the other is 16.65 k ohms. Did I just get a faulty plug since these are non-resistor plugs or is it not worth taking it back and exchanging it?

 

[arcticXS]

S

I know this is a subject on gap but I just bought new ngk plugs and did a resistance reading of electrode on one is near zero or 0.03 ohms and the other is 16.65 k ohms. Did I just get a faulty plug since these are non-resistor plugs or is it not worth taking it back and exchanging it?

Sounds weird. Resistor plugs are usually 5kOhm, arent they?
I'd measure again, both plugs in both directions/polarity, before going back to the shop.
Also, are you sure they are genuine NGK? I think there has been some cheap (chinese?) copies on the market earlier. Google "genuine NGK" or something to that effect to find out more.

 

[Bushyeyed1]

They are NGK off the shelf from the auto parts store. I read it multiple ways and still shows the results.

 

[ReycleBill]

For a dual output coil and electronic ignition, I go with a .032" plug gap. For the wimpy stock dual coils and points ignition, I stick to the recommended .028" factory gap spec.

A local guy called me one time because his 650 wouldn't start. He had just installed brand new plugs. I went over to have a look. I checked the gaps on his new plugs first thing. He hadn't checked or adjusted them from the way they came. NGK had them gapped very big, like in the 40's. I re-set the gaps to the recommended .028" (he had a stock points ignition and coils) and the bike started right up.

I've been telling people for years there is no such thing as a pre-gapped spark plug. I drove trucks for a living, spark plugs are one of the thousands of things I have hauled. I know how they get handled in distribution centers, trailers, and warehouses. And the farther they travel the worse it is.

 

[Paul Sutton]

I bought NGK resistor caps 3 year back and they showed as open circuit on the meter. I threw them away and assumed they were counterfeits. Bought two new caps from an auto store and they gave approx. 5kOhm as expected.

 

[Jack]

NGKs premium plugs followed by a prefix # say 11 at the end of part # is the # of thousandths plugs are pre gapped from factory but thats's not say
it's the right gap for your application. You do not gap Iridium or platinum plugs cuz of the finer electrode due to the likely hood of breaking the tip off.
AS far as plug gaps goes,if your coils produce a higher voltage to bridge the gap, then go for it till misfires occur,then back off slightly till power regains.
Wider plugs gaps aid in promoting a more efficient combustion but at the expense of electrode wear.