Question about Spark Plugs/Caps/Wires & Combinations

[ghoulgang]

I have a question about Ohms/Resistance of the whole spark plug system. Im an electrical n00b, but I was hoping someone here would be able to help me out.

I ordered new caps/wires/plugs from xs650direct.com (mikesXS in canada) - the description of the NGK plugs said that the 1k Ohm plug caps were reccomended for ignitions with points (my bike has points ignition - 1978 Xs400 E) so I got those, along with the irridium plugs (bpr7 equivalent) and some high performance spark plug wire.

I dont know the original resistance on the plug caps my bike is currently running, but they are testing high and I was told to replace them soon when I got my bike inspected (on purchase) anyways, they are the kind that accepts the threaded terminal end of the spark plug (without the screw on piece which I assume is a resistor) these worked fine with bpr7's (non irridium, with the screw on resistor removed) until recently when I lost spark on my left side. Im going to cross wire the coils to rule out the left side coil as the source of the problem, but I just had a question about the resistance levels.

the 1k Ohm Caps i ordered have a connector that only accepts plugs with the screw on resistors in place. Should my ignition system work with irridium bprex7 with the resistor cap on, and with 1k Ohm caps? did I order the wrong caps and need 5k Ohm ones?

What does the resistance in the circuit do for the system, and what happens if its over/under powered? will it produce too hot of a spark? no spark at all? Just looking for a any wisdom on the subject.

Thanks guys!

 

[16VGTIDave]

The small brass piece that threads onto the spark plug is just an adapter, nothing more.

The higher the resistance in the cap, the hotter the spark will be, within reason of course. The spark will also be shorter duration, so like everything else it is a compromise. If the resistance is too high, the spark may find an easier path to take, including burning out the coil.

You should be okay with the 1K Ohm caps and Iridium plugs, as the plugs also have resistors in them.

 

[Scorpio1963]

Strange I looked up irridium bprex7 on google and theres no search results

 

[arfstrom]

http://bit.ly/1cvq64g

I found a few hits for you Scorpy

 

[Scorpio1963]

Thanks Arfstrom
Questio from what I have read about these plugs can I use resistor type plugs on my 81xs or is just for bikes that have point ignitions?
My plugs need to be changed pretty bad.Also do these plugs get ruined if they get fuel soaked?This is one reason why I have changed mine yet cause my carbs are out of wack and need to be sysnc still.Also its been a couple of weeks since my bike has been started.

 

[arfstrom]

To my knowledge they are fine if you soak em, gas will evaporate natural, so no, the would be fine. I just got a tablet, realize my thoughts do transfer as easy as it does with a real keyboard.

NGK plus are resister, aren't they. I just googled NGK plugs and their web site says standard or iridium plugs are fine. Which I could do page prints like a computer.

 

[16VGTIDave]

To my knowledge they are fine if you soak em, gas will evaporate natural, so no, the would be fine.

If only life were that simple! Years of experience has proven that if NGK spark plugs get fuel soaked, they will misfire until replaced. I don't know if this applies to the Iridium plugs, they didn't exist when I was working at a Nissan car dealership. But we replaced thousands of plugs each winter for this very reason. I've been told that when VW was using NGK plugs, that they had similar findings.

I have recently installed DR8EIX plugs in my DOHC and haven't flooded it, so I don't know if they will perform differently. And with the price of those plugs, I hope to not find out!

 

[XSLeo]

I think buying those Iridium plugs online is costing way to much. I found them at the local parts store for $7 each, much better than the $10.50 Mike's charges.
I tried them and didn't think they were worth it. I run the Auto Lite AP63 plugs. They are around $5 a pair at Wal Mart.
Leo

 

[Scorpio1963]

I think buying those Iridium plugs online is costing way to much. I found them at the local parts store for $7 each, much better than the $10.50 Mike's charges.
I tried them and didn't think they were worth it. I run the Auto Lite AP63 plugs. They are around $5 a pair at Wal Mart.
Leo

Since Im on a budget I will probaly give these a try.Thanks Leo
I have autolites in the bike right now but they are old.I have fuel soaked them many times and they are still going strong.

 

[Scorpio1963]

So I bought a set of Auto Lite AP63 plugs for my bike today.Look like a good plug but havent had the chance to fire up the bike with them yet.

 

[arfstrom]

$2.49 at O'Reilly's Autoparts For the plugs anyways,,,
http://www.oreillyauto.com/site/c/detail/NGK1/5534.oap

 

[Scorpio1963]

I bought my plugs at Oriely`s

 

[arfstrom]

My math sucks, but I think If I bought 2, it will be for 5 usd, plus tax I suppose, so it wont be 5 bucks.