spark plug end caps

[mikesmold]

If you test thre wire 0 ohms it is copper. In the end cap there is a resistor of some kind. can't be tested with o meter. How do you know if it is good or not.?

[gibvel]

V7Goose knows all about this. Hopefully he'll chime in with his wisdom.

 

I believe that they should read about 10K Ohms. The caps can be unscrewed from the wire and there is a brass screw inside the cap. If you unscrew this there are about 3 pieces inside that. There's a spring, a brass spacer and the resistor. If you do this be careful not to lose any of the parts. The brass spacer is pretty small (some of mine were cracked into smaller pieces and I ended up making some to replace them).

 

My springs were pretty corroded. I took a wire wheel on the dremel tool and cleaned them and the brass screw that holds everything together. DO NOT, I repeat, DO NOT take anything abrasive to the ends of the resistor to clean them. The coating on the ends of the resistor will come off if you breath on it wrong and then your cap will be useless.

 

The spring goes in first then the brass spacer then the resistor then button it all up with the brass screw. Then you can screw it back into the wire.

 

Like I said, the resistance should be close to 10K Ohm, I believe. I'm not 100% on that but I'm 90% sure that's what it should be. I believe most of mine measured close to 9K when I was doing mine.

[V7Goose]

Everything there is correct. Nothing magical about measuring the resistor with an ohm meter except you should do it simply by leaving the cap assembled and measuring the whole thing together. Anything over 12K is a problem.

Goose

[gibvel]

Yeah, guess I should have said that about measuring with the cap assembled.

 

Guess I gave more information than he needed. Was going into the what to do if you get a bad measurement.

[PEIslander]

The original resistors are 10k ohms but the replacement ends from NGK have 5k ohm resistors. The resistance value is not critical but if the resistor is open circuit then the spark will be weak or it may arc somewhere else.

 

Rick

[mikesmold]

open circuit on all resitisors. Checked with two different ohm meters. going to go to napa and get NGKs. They are orignal, I think all yamaha Thanks for all your imput mike

[Monty]

When I had my '83, and since I was using resistor plugs, I took out the resistors and replaced them with small pieces of copper wire with the same length and diameter. The bike started up and ran soo much better after that. There was no sense in having double the resistance.

[camos]

I took out the resistors and replaced them with small pieces of copper wire with the same length and diameter. The bike started up and ran soo much better after that. There was no sense in having double the resistance.

10 gauge copper wire should do the trick.

[mikesmold]

That was my next fix. Just didn't want to seem crazy. makes sense to me if you have resistor plugs, you don't need two. still going to try the ohms test on the NGKs before buying. because all mine are open circuit. thanks for the help mike

[cimmer]

If you havent gotten them already. Dennis Kirk stocks them too and he is just down the road from you there. You can also pick up non resistor wire and replace caps and wires while you are at it.

Something to think about..

Rick F.