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[Wheaters]

I don’t see any reference to anyone claiming extra power. Someone seems to have made that up.

[trophyvase]

I was thinking of a couple of comments - 'improved the bike's running all round' and 'a dyno run would show the efficacy of the iridium'.

Apologies if I misunderstood. But 'all round' seemed to include power and a dyno is normally used to measure power.

Incidentally - I'm all for iridium plugs - NGK or Denso.

[PeteF]

What a strange line of thought this thread has produced!

By the nature of the case a spark plug of itself cannot increase power. It provides a spark. That spark may be weaker or stronger – either way a spark causes combustion of the fuel charge. The spark cannot determine the power produced by that combustion. The potential of combustion is affected by volumetric efficiency and/or thermal efficiency. Neither of which are affected the type of spark plug - so long as the spark plug sparks!

Quite right. The spark either initiates combustion or it doesn't.
OK, an iridium plug might last longer and be more reliable, but it can't increase power.

[Trev]

My iridium wonder turned up today while I was hooning back from Cornwall on a very non-Enfield bike. Will be fitted tomorrow and I'll see how many gears it will lift the front wheel in

[stinkwheel]

I could see it helping idle purely due to the amount of oil these bikes burn. More likely to spark every time in the presence of oil and carbon.

I keep meaning to try side-gapping a standard plug, I suspect this may have a similar (or even better) effect.

[Beezabryan]

side-gapping ?

[stinkwheel]

side-gapping ?

Off topic because it costs considerably less than a tenner.



Here's an article about it showing measurable improvements in combustion efficiency and power output, particularly at lower rev ranges.
https://www.researchgate.net/profile/Ri ... ission.pdf

[PeteF]

Can't help thinking that if side gapping was so good then manufacturers would do it as a matter of course.
There are all sorts of other electrode arrangements of course.

[Wheaters]

I could see it helping idle purely due to the amount of oil these bikes burn. More likely to spark every time in the presence of oil and carbon.

I keep meaning to try side-gapping a standard plug, I suspect this may have a similar (or even better) effect.

Yes, it might well have an effect; like "indexing" the spark plugs also can do. However, due to the cheaper metals used on a standard plug side electrode it might not last as long.

As far as trying it, to save about £3 or 4 over an iridium, in my case it pales into insignificance considering all the other stuff I've bought for the bike.

[Nitrowing]

As far as trying it, to save about £3 or 4 over an iridium, in my case it pales into insignificance considering all the other stuff I've bought for the bike.

Yeah, the cost difference on a single isn't really worth penny pinching over.