Z1OwnersClub GB

Gonna change the NGKs on my 79 Z1000 for Denso's next time so are W24ESR-U the correct ones to use ? cheers all

Depending on plug cap you want W24ESR-U for resistor type or Denso W24ES-U for the stock NGK B8ES non resistor equivalent or Denso IW24 for Denso iridiums.
If going hotter or colder then Denso 22 is NGK 7 equivalent heat range and Denso 27 for NGK 9 .

Ummm I've got B8ES plugs now so would resistor R type Denso's not be right ? sorry to appear thick !!

Hi Alan

in my experience the "R"-type spark plugs are not good, they fail after a few short runs, I think the "R" stands for "Really fast broken" instead of "Resistance".
I use the NGK B8ES and I'm satisfied, I have no experience with the Nippon Denso spark plugs.
Good luck
Philippe

Treat yourself to decent IW24 Denso's (Iridium) - been running those for years in all me Zeds & they've never let me down, unlike NGK

What piggy says

Ditto two many cheap copy Chines Ngk,s about.

AlanB wrote:Ummm I've got B8ES plugs now so would resistor R type Denso's not be right ? sorry to appear thick !!

Use Denso non resistor W24ES-U as a straight substitute for the NGK B8ES.
B8ES's are non resistor.

PAULJAC47 wrote:Ditto two many cheap copy Chines Ngk,s about.

Never had any trouble with genuine NGK's.
Chinky copies are easy to spot.
http://www.ngk-sparkplugs.jp/english/te ... index.html

Just thought I would ask Sparkplugs.co.uk as when I search that site for suitable plugs for a 79 Z1000 it suggests the Resistor (W24ESR-U) type - They say that Denso only recommend the resistor type (Or Iridium which also has a resistor) for any Z1000 model and if I decide on the non resistor (W24ES-U) type, there will be no come back if any probs etc !! Any thoughts guys ?

I have published this from NGK before but still worth a read.

If I decide to treat myself to Denso IW24 Iridium plugs, will they fit and work with stock ignition/plug caps etc (Currently using B8ES NGK plugs) as I understand they are "Resistor" plugs too ? Cheers.

AlanB wrote:If I decide to treat myself to Denso IW24 Iridium plugs, will they fit and work with stock ignition/plug caps etc (Currently using B8ES NGK plugs) as I understand they are "Resistor" plugs too ? Cheers.

BR8ES is the resistor version of the B8ES you have been using, so you have not been using resistor plugs.

Theoretically, you don't need resistor plugs if you have resistor caps. In reality however, the advice given to me by an NGK tech was that the resistance of the spark gap is infinitely higher than the internal 5k of a plug and or cap so, the effect on the produced spark is negligible. Furthermore, Iridium plugs produce a better spark at comparatively lower voltage. So go ahead and treat yourself

I have used both denso and NGK plugs, but always go back to NGK, never had problems with either, that said i have no serious performance upgrades, and don't race so have no need to play around with different grades of plugs, i never buy from the web because you never know what you may get, i pay through the nose at a dealership and always have a receipt in case i get a duff plug which has never happened, my bikes ain't broke now so i don't try fixing them. Happy new year chaps.

The difference between Denso and NGK seems to be in the comparative heat range of so called equivalents. Denso W24ESR-U running a little hotter than NGK B8ES. This tends to work better given the riding styles and colder burning fuels of today in classic engines. NGK research suggests use of a hotter plug than originally designated 40 years ago to compensate for the change of usage and conditions of today. A B7ES being their recommendation.

Buying online is no more risky if buying from a reputable dealer. This advise should help.