OK book list .030-.040 sounds like a pretty big range to me.Mine(stock ngk) came set at like .032 So it'll be Ok.But what would be best?

I believe by theory, the wider the gap the hotter the spark.

The -9 in CR8XEH-9 denotes gap in tenths of a millimeter, so it should be about 0.036". This is fine for the 919, which seems to have enough zap to light the fires even with gaps exceeding 0.040". The wider the gap, the hotter the spark only up to a point -- even if the energy from the coils is sufficient at idle, it may not be at higher loads, where the higher pressures make the formation of the ionization path (necessary for spark formation) much more difficult. Stick close to the recommended gap.

Rob

You're suppossed to have a gap?

You're suppossed to have a gap?

Yep, you fill the gap with the plug...

Ok so I'll leave it at 32ish and if for anyreason I need to lift the tank again,I'll regap them to 36ish.

BTW #3 is reason enough to remove the pairs system,I really didn't give it much thought till I changed plugs this time.

I just bought four NGK Irridium plugs to put in this weekend. The invoice has a statement printed on it that says, "Do not gap these plugs, you might break the electrode!" I have not opened them to check the gap but if they are not right on, I'm just going to gap them for the recommended .035" (recommendation from NGK for the 919).

I just opened the boxes on my Irridium plugs. They are gapped at .035 so I don't have to worry!

I've been using irridium for the past 2 years and love them.... better top end response on the track with them.