Spark Plug Cap Resistance

[BlueSky]

From what I understand, the stock spark plug caps have a resistance of about 9k ohms and the NGK replacements have a resistance of 5k ohms. My bike evidently has the OE caps that have 9k ohms resistance. If I use the NGK caps, will this cause a problem with the TCI? Can it handle the lower resistance?

Thanks!

[bongobobny]

It shouldn't. By lower resistance causing an issue, that would be more along the order of not using resistors at all, like only a couple of ohms. Also, the TCI is more concerned with the primary coil resistance than the output load resistance...

[BlueSky]

The spark should be better with the 5k ohm caps, so it should be a good mod if there are not detrimental effects.

[djh3]

Just so happens this is kind of the material my student had this week. Ignition systems, principals and operation. 4 ohm difference in the cap "should" not make large difference. Couple things to think about 1-is this a direct replacement IE:is this what is now the oem replacement? If it is or recommended as replacement they have figured out if it will work OK with other ignition components like the ecu or what have you. 2-possible shorter plug life because you will now have more volts running to the plug with the reduced resistance in caps. 3-Possibly interference or "buzz" in you radio and electronics

[BlueSky]

Just so happens this is kind of the material my student had this week. Ignition systems, principals and operation. 4 ohm difference in the cap "should" not make large difference. Couple things to think about 1-is this a direct replacement IE:is this what is now the oem replacement? If it is or recommended as replacement they have figured out if it will work OK with other ignition components like the ecu or what have you. 2-possible shorter plug life because you will now have more volts running to the plug with the reduced resistance in caps. 3-Possibly interference or "buzz" in you radio and electronics

 

It's a 4k ohm, 4,000 ohm, difference in resistance in the two caps.

[djh3]

So 4k between 2 caps, I would like to think not going to be a problem. Shoot you can almost get that in wires over 12-14" long.

[BlueSky]

So 4k between 2 caps, I would like to think not going to be a problem. Shoot you can almost get that in wires over 12-14" long.

 

The wires on the Gen Is are copper core that essentially have no resistance.

[cowpuc]

Not that I know nuttin about nuttin when it comes to understanding resistances, Ohms Laws (I do know about helmet and speed laws somewhat) or none of that engineering stuff BUT - thought I might add that our scoots do spec resistor plugs too. A long time ago I was yakking with a genuine, certified Mom Yam factory tech about some of this stuff.. I had discovered the resistor caps on my 1st 1st Gen and knew my plugs were spect out resistors. Had a plan formulating that getting rid of the plug cap resistors and resistor plugs (going to a simple D8ES) may result in some nicer, more effecient sparkin.. I was actually warned about potential TCI damage by doing so by that tech.. In my mind, I reasoned that because of the primary coil separation in windings as Bongo mentioned - how could this be.. Was told dont do it, not worth the risk of TCI damage (much less the radio interference that it might cause to those around me listening to radios and so forth).. @BlueSky,, I am very glad you posted this question.. Would LOVE to jump into the classroom here and listen to some electrical guru's bat that question around a bit.. If nothing more than a little better understanding of electronic interference came out of it I would even be thankful for that..

Good thread IMHO..