Can't honestly say I've ever noticed the difference between Equiums or NGKs, I've towed boats, thrashed cars at 75 and pootled round town on both.

Another +1 on NGK 7HS plugs (might even stretch to 8's). I used them for years and never had any problems and I like to 'exercise' my engine ! If you have trouble getting them, try your local m/bike shop.

Ive never had a problem with ngk's,
However the equem plugs did let me down,
I use b6's in mine faultlessly

I've been using B7HS in 8.5:1 engines and B8HS in 9.0:1 engines for over 15 years.
With B6HS, there could be problems with 'running on' after the engine was switched off, which indicated that their heat range was too hot.

ken

p.s. http://www.eyquem.com/

Nul points for 'Equiums', 'Equim' or 'equem'...

Ken
Sorry for the spelling mistake

Odd you mention running on, because however spot on the timing is, it runs on a fair amount of the time

I've never tried b7hs, next time I'm short of plugs I may try them based upon the above opinions

I've only ever used NGK plugs in mine (probably just because they're easier to get hold of), have never replaced a pair as early as recommended, and have never had one fail in a car, or even show signs of deteriorating. That does mean though, that I end with a small collection of used spark plugs, including some Bosch and Eyquem that have been in cars when I've got them, which then tend to get used up in ratty two-stroke bikes. Old Eyquems seem to be absolutely hopeless for this, and the only Bosches I've got came out of the Dyane boot, so the fact they work at all after I've dug out all the rust around the insulator is pretty impressive, but NGKs seem to last very well even second time around.

That said, I've just about ruined all the old plugs I have now, so if anyone else can't bear to throw anything away, and has a little stockpile of almost worn out sparkplugs doing nothing, let me know!

Also on the subject, does anyone have a link to an idiot's guide to heat ranges, as it's something I've never really got my head around properly?

Not very good photos i'm afraid as taken on my phone but you should be able to make out the difference between the plug that came out of the nearside



and the one that came out of the offside



After not even 100 miles!!

I have heard of problems with ngk's of eBay.. But they (after the problem) where believed not to
Be genuine

@ Luke,
not an idiot's guide, but a very good one...
http://www.ngksparkplugs.com/tech_suppo ... ugs/p2.asp

Interesting stuff on page 4, specifically concerning fuel type and ignition timing.

Always remember that plug manufacturers like to set a little trap for the unwary, with NGK's heat range being 'the higher the number, the colder the plug', whereas Bosch and others use the reverse.

@ emu_p,
pity that the photograph is so blurred, since that looks like physical damage.
The only time I've seen an earth electrode that shape was when the plug had been dropped...

ken

Well I had a new Eyquem doing this after 2 weeks. Only one for a long time. Sold heaps without any problems, same for NGK B6HS. Naturally odd one with fail one way or another from time to time. Won't speculate why but one can't always blame the plug.