Ducati Monster Forum

Moto Board => Tech => Topic started by: memper on September 12, 2012, 05:29:56 AM

Title: Question about plug size/rating
Post by: memper on September 12, 2012, 05:29:56 AM
In my Haynes it says to use 6's. NGK parts finder says to use 8's.
I have a couple of NGK iridium DPR8EIX-9's. Can I use em?

Carbs have a stage 2 kit, FBF pipes and it runs a tad rich.
Title: Re: Question about plug size/rating
Post by: Howie on September 12, 2012, 06:00:08 AM
Get these, they will work just fine.  And they are now Ducati approved.

NGK DCPR8E NG4339

4439 gives you the correct head size and the removable terminal cap.  Should be less than $4 a plug.
Title: Re: Question about plug size/rating
Post by: memper on September 12, 2012, 06:00:22 PM
So Howie, are the ones you listed "8's"?
Will the spare iridium "9's" I have be too high of a spark? Not safe? I suppose if my current plugs are real sooty they might actually work out (considering they are of equal length).
Title: Re: Question about plug size/rating
Post by: ducpainter on September 12, 2012, 06:03:13 PM
The plugs howie listed are 8's.

9's would be hotter.

If you need 9's you have a fueling problem
Title: Re: Question about plug size/rating
Post by: memper on September 12, 2012, 06:16:58 PM
gotcha
Title: Re: Question about plug size/rating
Post by: koko64 on September 12, 2012, 07:14:49 PM
Quote from: memper on September 12, 2012, 05:29:56 AM
In my Haynes it says to use 6's. NGK parts finder says to use 8's.
I have a couple of NGK iridium DPR8EIX-9's. Can I use em?

Carbs have a stage 2 kit, FBF pipes and it runs a tad rich.

I use those iridiums. 8 for NGK heat range and -9 for quite a large gap. Those large gaps may be a bit too much for stock coils, but can work well with high output coils and leads.
One day, when there are no wars and poverty is eradicated, the spark plug manufacturers will use the same number codes.
Title: Re: Question about plug size/rating
Post by: motoxmann on September 14, 2012, 07:08:05 AM
um, aren't higher numbers Colder plugs? meant for use in hotter engines and/or hotter weather? meaning a 9 would be too cold in a stockish Duc...
Title: Re: Question about plug size/rating
Post by: koko64 on September 14, 2012, 07:29:17 AM
True for NGK, but is it Bosch or Champiom that go the other way?
The code isn't standardized unfortunately.
I remember a customer getting what he thought were Denso equivalents to Champion and NGK plugs for his hi comp M944 and having problems..
Title: Re: Question about plug size/rating
Post by: ducpainter on September 14, 2012, 09:04:24 AM
Quote from: koko64 on September 14, 2012, 07:29:17 AM
True for NGK, but is it Bosch or Champiom that go the other way?
The code isn't standardized unfortunately.
I remember a customer getting what he thought were Denso equivalents to Champion and NGK plugs for his hi comp M944 and having problems..

Champions use lower number for colder plugs.
Title: Re: Question about plug size/rating
Post by: koko64 on September 14, 2012, 12:37:38 PM
Quote from: ducpainter on September 14, 2012, 09:04:24 AM
Champions use lower number for colder plugs.

Thats right, a never ending cause of confusion.
I remember way back in my Harley ridin' days...  My "bros"  warned against those "crap NGKs always foulin', stay with Champion".  [laugh]
Title: Re: Question about plug size/rating
Post by: ducpainter on September 14, 2012, 01:13:36 PM
Quote from: koko64 on September 14, 2012, 12:37:38 PM
Thats right, a never ending cause of confusion.
I remember way back in my Harley ridin' days...  My "bros"  warned against those "crap NGKs always foulin', stay with Champion".  [laugh]
I used to used the fine wire electrode 'G' plugs in my 2 stroke.

Back then we'd use auto coils, for the increased voltage, and wide gaps with the fine wire plugs and never oil foul a plug.
Title: Re: Question about plug size/rating
Post by: koko64 on September 14, 2012, 01:40:48 PM
Quote from: ducpainter on September 14, 2012, 01:13:36 PM
I used to used the fine wire electrode 'G' plugs in my 2 stroke.

Back then we'd use auto coils, for the increased voltage, and wide gaps with the fine wire plugs and never oil foul a plug.

I was alluding to market prejudice.
NGK are the plugs of choice for me. I run big gap iridiums with strong coils.
Back in the day, some people had issue with where the plugs were made (and confusing the plug codes). Didn't bother me, I ran a Mikuni flatslide on my Harley when everyone else ran S&S, if you know what I mean.
Title: Re: Question about plug size/rating
Post by: ducpainter on September 14, 2012, 01:42:24 PM
Quote from: koko64 on September 14, 2012, 01:40:48 PM
I was alluding to market prejudice.
NGK are the plugs of choice for me. I run big gap iridiums with strong coils.
Back in the day, some people had issue with where the plugs were made (and confusing the plug codes). Didn't bother me, I ran a Mikuni flatslide on my Harley when everyone else ran S&S, if you know what I mean.
I got it... ;)