spark plugs

[Les666]

I have seen an advert on ebay for NGK Iridium spark plugs, works out at about £32 for the four...questions...Do Iridium plugs make any big difference, if so what?? Is this a good buy, can I get them cheaper elsewhere or should I just go to the pub and spend it on beer..

[old red eyes]

[xrv_jim]

I think there have been a few discussions about iridium plugs in the forums. The general concensus is that you get a few more mpg and smoother running - plus they last longer. I think I'll give them a try next time I change the plugs.

[robelst]

I think it's mainly a load of bollocks, invented by an exhausted uninspired automotive industry where everything has been invented already: a spark is a spark, a bigger "stronger" spark is not necessarily a "better" spark because fuel will ignite anyway, fuel is still ignited at the same place at the same time so the explosion is not "different" or burning would be quicker / more efficient. It is simply not possible an engine would suddenly smooth out because the spark itself is not part of the actual running of the engine (provided you'd compare these uber-plugs with good quality conventional plugs that are not worn or defective). Iridium and platinum jobbies do have slight advantages in catching less dirt (particularly important when using cold plugs in highly tuned engines under low load / idling) and live longer but not 3-4 times longer, as the price should justify. The biggest advantage for AT riders would be having to change that little bugger-plug in the front cilinder less often :P

If you want to have faster and more efficient combustion, ignite fuel at two different places at the same time. And hey, that's exactly AT/TA's have already

So: better stick with the lager imho

[Maverick]

I have used Brisk spark plugs on a different bike before and the motor was smoother at lower revs, a £10 a plug it only lasted 6k miles which was not so so good.

[fewtrees]

I have iridium plugs and the bike is noticeably smoother running than standard plugs.

I was quite sceptical and the plugs were changed when the bike had only done 2500 miles from new. The old plugs were fine and showed the bike was running on the correct mixture. I think that means it's a reasonable comparison, changing good plugs for iridium ones that still demonstrate an improvement, instead of changing bad/fouled plugs for any new plug that would show some kind of improvement..

[Les666]

thanks for replies, I have decided to go for it and change the plugs....off now to ebay to order some up, will let you know when they go in and any change I notice.

[Dilbert]

Wemoto have them also at £8.81
http://shop.wemoto.com/index.dyn?oid=25392
this link is for the later model, but they do the earlier 750cc and the 650cc also.
and I'm sorry but a spark is not a spark otherwise we wouldn't have all bought the copper cored ones when they first came out, better conductance and a higher or more controlled surface temperature provides a more efficient and even burn of the fuel and burns more of the fuel content (hence better mpg).
the only way to be sure is to take notes with standard plugs and compare these with what you get (or feel) after fitting the Iridiums, if it gives any noticable difference let me know, I may be interested in fitting them to mine.

[mal]

Why does the@ have twin spark plugs per cylinder ? does it give it more power or better emissions?,or a combination of both

[Dilbert]

As Robelst pointed out above two plugs gives a better spread of ignition, but that's not to say that it can't be helped along a bit, hot sparks aren't necessarily better, best thing is a slow long burn evenly spread.
the other way to improve things is by gas flowing the head i.e. polishing out and opening up the airways, fitting a free flowing air inlet filter and a low resistance exhaust, need to be careful though too little resistance and the exhaust valves won't close properly, gas flowing the heads and polishing is also expensive and may not give a huge difference in bhp and is very easy to get wrong!

there again it could also be that when racing across Africa if one plug goes down there's still another popping away