Iridium Spark Plugs

[Barry]

They can red or black for the same value. I was going to say look at the ref' :-

LB05F would be 5k ohms but as Bob says you have to measure the resistance as there is no indication on the cap itself.

Mine are red and measure 5.0k spot on.

[Semper Gumby]

OK here is a picture.  The 5k ohm has a longer shaft that contains the resistance element and also has the raised section with "NGK" embossed on top.

The 0 ohm has a shorter high tension lead connection with the letters "NGK" raised alone.  In the picture it is the one connected to the wire.  BTW there is no erosion of the iridium tip after 30,000 miles.  Now the out side needs some attention tho.....

[Bob_Roller]

Alright, I learned something today, so the day hasn't been a total loss .

[Semper Gumby]

Well I've never seen red caps but that doesn't mean they aren't out there!    8-)

[Bob_Roller]

Did you get the non-resistor caps from a local source, or did you have to order them online, etc. ?

[Semper Gumby]

My local motorcycle shop ordered them out of their supplyer's catelog.  Took some pointing by me to get them to order the right part.  They didn't understand that there was a 0 ohm sparky.  Having the correct part number should have been enough but....

[Barry]

Well I've never seen red caps but that doesn't mean they aren't out there!

NGK call them red, reddish brown would be a better description so they are not to bright and they fade to brown as you can see. Here is a link that gives full details of  NGK's range of plug caps.
http://www.ngkpartfinder.co.uk/files/NGK_Spark_Plug_Covers.pdf
Sun glasses not required

[Semper Gumby]

Well I'll be.  Hey that looks like a resistor cap though.  It's got the longer shaft.

[montmil]

Sun glasses not required

I'd never trust anyone with an engine, or a house, that clean! [smiley=thumbsup.gif]

Where ARE those shades of mine?   Monte

[Barry]

Sun glasses not required

I keep telling you guys that the camera always flatters.  [smiley=camera_sm.jpg]

What I meant was you wouldn't be needing sunglasses for a bright red plug cap.

Strange that this red colour seems so unusual over there. It was quite a common colour for electrical bits like distributor caps on old cars. Perhaps mimicking when they were made from Bakelite.

[ukzknos]

Yes.BPR7EIX - I run them with the 0 ohm ngk spark caps.  


I guess you are using 0 ohm plug caps because they are resistor plugs.  

I can't find any NGK data to suggest that these are resistor plugs so shouldn't they be run using resistor caps?

[Barry]

BPR7EIX

The R in a spark plug code indicates it's a resistor plug so your right to run with 0 ohm caps.

B = 14mm thread
P = Projected nose
R = Resistor
7 = Heat range
E = 19mm thread reach
IX= Fine wire Iridium electrode

[ukzknos]

Barry

As I have considered putting some of these plugs in mine this spring what happens if you have resistor plugs and resistor caps?

Thx
Steve

[Barry]

Well there is no short and complete answer on this one.

The theory goes that excessive resistance will rob the spark of a little energy so it is not a recommended combination if your still running points ignition on your 1980 which is a more marginal system than the later electronic ignition. Below something I've got on file. Also Snowbum has some wise words on this topic:- http://bmwmotorcycletech.info/sparkplugs.htm

RESISTOR PLUGS
What are Resistor Plugs? Well by now you might have realised that the major part of the resistance in the F Plug/Coil system is provided by the Plug Cap. Some bikes use Resistor Plugs, so another solution could be to just have a 0kohm Cap and Run Resistor Plugs in your bike, but not both!
·      MPG on my R80G/S went up about 10% when I realized I was running resistor plugs AND resistor caps and changed to zero Ohm caps. DOH!
·      NGK do make a resistor plug, the NGK DR8EA. The OEM cap was 1kohm. Substituting a 5kohm cap is probably OK.  A 0kohm cap without using a resistor plug like the DR8EA is NOT OK. If you use anything (but) more than 5k, you'll probably get less spark than you would with 5k due to impedance mismatch.  But using 10k would probably be just fine in practice.  But for good fuel economy DON'T use both a resistor cap AND a resistor plug. In other words, I don't think it really matters all that much one way or the other as far as making the bike run. Economy might suffer slightly. But would you really notice?

·      I may be way off base, but I thought the resistor in the stock plug caps performed the same function as an "R" type plug. True? If so, adding an "R" plug would simply be adding more resistance

[ukzknos]

Electrics have never been my forte, more of a mechanical type.

Thanks for the advice!