Spark plugs

[tony.mon]

The standard plug for all models of the Firestorm/Superhawk is DPR9EVK-9 . This is the fat electrode non-Iridium plug.

However the upgrade plug is NGK's DPR9EIX-9 Iridium plug, or its direct equivalent in other ranges. This has an Iridium electrode which gives a cleaner, finer spark, and doesn't wear away like the standard one does.

But beware; it can't be cleaned with a wire brush or in a spark plug cleaning machine, so they are a non-adjustable disposable item.
I'd recommend that you replace the plugs every 5,000 miles or so, more often if you use the bike in a harsh environment, trackdays etc.

There is an alternative, NGK's DCPR9EIX-9. The extra "C" means that the hexagonal "nut" part of the plug, gripped by your plug spanner, is only 16mm across flats instead of the DPR's 18mm. Your toolkit plug spanner won't fit properly, but might work ok if the plug's not too tight.

So if the plug spanner doesn't fit properly on the plug, someone's fitted the DCPR version instead.

All other aspects of the plug are identical, so no need to change them if you have the DCPR version fitted; just be aware of the smaller AF measurement.

Although the fat electrode DPR9EVK-9 is a pound or two cheaper; I wouldn't recommend using these unless in an emergency, or to do more than get the bike running for a day or two.

You won't do any damage, but the difference in engine performance, pickup (and probably fuel economy as well) is noticeable using Iridiums over standard ones.
I've tried a couple of other brands of Iridium plugs, and can report no noticeable difference, except that they're dearer.

Best price seems to be on Amazon, and the best deals are for sets of four plugs, so I'd suggest that you split the purchase with another owner and get them cheaper.

[edds11]

nice one tony..again. I knew plugs made a difference but didn't realise it made that much on a VTR, but if you think you only have 2 bangs, they need to be good ones.......do they help with the 2500-3000 farting

[VTRDark]

That's very interesting Tony, Why would they change the hex size The other thing I have noticed about Iridium plugs over standard is that you can't read them to check engine tuning/mixture conditions, they don't seem to colour the same.

I think I got mine from Aceparts they were about £10 for 2. They usually sell on the bay as well, but don't have any at the moment.

(:-})

[tony.mon]

Why would they change the hex size

It can only be because of access.
The Storm engine has quite deep/restricted access for getting to the plugs, which is why most standard plug spanners won't fit.
In some other engine designs access might be even more difficult, and an even smaller spanner is necessary.

If you look on NGK's listings, these plugs also fit a lot of Ferrari's, amongst others, bikes as well as cars. I think I saw on the list that the new Aprilia V four takes these as well.
These applications are usually deeply recessed into the heads, and with various bits of plumbing getting in the way.

[VTRDark]

Argh yes, that would make sense. Same plug fits others = cheaper production.

(:-})

[tony.mon]

So as a seriously blingy upgrade (are you listening, Marty?) you could fit DCPR plugs and buy a Ferrari plug spanner to remove them with.
Must be worth 10MPH at least.....

[benny hedges]

was shopping for sp2 plugs before
and heavy duty chain n sprox - £180
think yourself lucky lol.

[sirch345]

Very interesting Tony

Chris.