Resistor or Non-Resistor

I have a 1981 XJ650. I understand they came stock with a resistor spark plug cap. What I want to know is what would happen if I changed the plug caps and wires to a non-resistor type?

 

Then you should run resistor plugs.

 

Basically, the more resistance, the less EMI you get from the spark that can mess with radios, gos, or any electronics.

When I got my bike it had resistor plugs AND caps, i went to non resistor plugs, and didn't notice any difference in the running of the bike. Of course i don't have any electronics on the bike yet to test if EMI is at a bad level or not yet.

BTW - EMI = Electro-Magnetic Interference

 

The bike was bought with hot running resistor plugs (BPR6ES). The #1 and #4 caps are a bit damaged. I took out the screws and found that the spring was missing on the #3. I replaced the spring with one from an ink pen. The bike now runs better. However, I am changing the plugs back to OEM non-resistor plugs (BP7ES). Also, I thought about replacing the caps with new ones. I just wasn't sure if I should replace them with resistor or non-resistor.

 

Using one of the two for resistor types is fine, but you want to stay away from using resistor caps AND plugs, it's redundant to use both and doesn't really give you any positives.

Running a cooler plug will most likely be a plus for keeping the chamber cool, and if you're goin to replace two plug caps, you might as well do all 4 just cause these are old bikes, and the caps are terribly expensive.

Rick had mentioned in a post it might be a good idea to cut back the plug wire by 1/2"to 3/4" if the end of it looks damaged or worn. BUT make sure you have enough plug wire available to make the trim BEFORE you trim it. You don't want to cut it and then find out the wire and cap, won't reach the plug

 

The same caps from Yamaha are outragously priced. Ran me $25USD for all four OEM NGK replacements from a bike shop. Guess I'll have to re-evaluate my definition of expensive. Hint: Avoid the stealership gouge and contact Chacal, he'll get you the correct parts at very resonable prices.

 

Old wives' tale: Plug "temp" in.. No way.. affects engine combustion tenperature.
NGK has a quite good educational section in their website .. Worth reading

 

Corrected, not sure what i was thinkin this morning hahah, colder plugs just have shorter ceramic, so it doesn't absorb as much heat - meaning the plug runs cooler.

 

has anyone ever used those plug caps with the little lights in them, if so would you recomend them. i have a ton of led's on my bike, and think they might add a little more light to the situation.

 

I have come across something with these plug wires I find interesting. My bike is having sort of misfire symptom. I thought it was fuel related but now I don't know for sure. the cap on the #1 cylinder is cracked however it idles fantastic and under hard accel its fine anyway, my issue is I went to check this cap to see if maybe it had given out. I check resistance with a volt meter and I didn't even get continuity. I was thinking ok this is weird. So I check the cap on the other side. The same thing. How can this be possible? I would think the bike would run a lot worse with this being the situation.

Any thoughts or answers would be great.

 

Arcing in a gap in the wires maybe? no solid connection

 

What exactly did you check? The exact number depends on specific bike model, and in some cases, which cylinder pair, but the total resistance from one plug cap to the other should be several thousand Ohms (at least 5K Ohms for each cap, plus the resistance of the coil secondary). There should be an open (infinite Ohms) from either plug wire to ground.