Is this supposed to happen....Spark plug wire....

Reading through the XJ4EVER catalog I see these do come separate, but is this supposed to happen, do i just push it back in, or how is that connected? Or does it need to be replaced?

 

if you remove the rubber boot on the end of the plug cap ,you should see a threaded screw. the cap screws onto the end of the wire, you may need to trim back the wire, 1/2 inch, if the cap is loose.
stu

 

Oddly, it looks like it is supposed to push on, no screw, just a sharp, threaded stud. Is this stock?

 

That is correct, it screws into the end of the wire. Looks original.

Test it with an ohm meter to see if it is the correct resistance on the plug. Mine were supposed to be 10Kohm (xj550k) but one was actually open. I believe some bikes only had 5Kohm resistance. What model is yours?

When I replaced them all, the bike ran mucho better. It had to have had a cold spark on that cylinder: http://www.xjbikes.com/forums/threads/sparkplugs.74079/#post-482270


If it is ok, take the rubber boot off, and slide the boot over the spark plug wire. You may nip a 1/4 inch off the end of the wire to get to fresh wire. Screw the plug back on the wire until it meets resistance and stops. The threaded stud "bites" into the wire core of the wire. Finally pull the rubber boot over the cap.

 

Thanks for the info, I assume I measure from the cap to ground?
It is an XJ650RJ
That plug was more powered black than the others, when checked awhile ago. Thought it was running rich, but maybe the wire was just not tight.

Looks like the cap itself measures 7.8k. I'll check the others

 

if by ground you mean where the spark plug goes then yes meter probe in one end and other probe in other end
XJ650 models:

Pick-up coils:
1980-81 XJ650 Maxim and Midnight Maxim: 700 ohms +/- 20% = 560 ohms to 840 ohms acceptable range
1982 XJ650RJ Seca (non-yics engines): 700 ohms +/- 20% = 560 ohms to 840 ohms acceptable range
1982-84 XJ650 Maxim: 650 ohms +/- 20% = 520 ohms to 780 ohms acceptable range
1982 XJ650RJC Seca (yics engine): 650 ohms +/- 20% = 520 ohms to 780 ohms acceptable range
1982-83 XJ650 Turbo: 120 ohms +/- 20% = 96 ohms to 144 ohms acceptable range
Ignition Coils:

Primary side (input from main wiring harness):
2.5 ohms +/- 10% = 2.25 ohms - 2.75 ohms acceptable range

Secondary side (spark plug wires, without their end caps):
11K ohms +/- 20% = 8,800 ohms - 13,200 ohms acceptable range


Spark plug caps:
5K +/- 20% = 4,000 to 6,000 ohms per cap acceptable range

Spark plugs:
0 ohms per plug

 

An intermittent misfire will not burn the fuel/air mix coming into that cylinder and will leave the plug black and sooty. Check through the resistance of all the points mentioned above, and get the cap screwed on properly.
You may want a new plug depending on how bad it is. Keep in mind that you should be running non-resistor plugs, and it should run fine after that.

Tony

 

New caps are money well spent
NGK LB05FP for cyl1and4
NGK VB05FP for 2,3
This Canadian 5ohm spec as we used resistor plugs
Us market 10 ohm and non resistor plugs

 

Thanks guys, as usual....a wealth of knowledge on this forum. And guys more than willing to help.