Dead Cylinder, i thought

[Martin2001]

2001 Tourer, 50k mi.
Pulled it out to ride today. It was a little tough to start, i figured it was just slow to get fuel to the carbs as i had ran them dry thinking it was going to sit for the winter. Once it started it seemed to idle fine. I got my stuff on and took off. It was running like the tank was dry although it shouldn't have been, only 90 miles on the tank. Switched to reserve, no change. I turned around and headed back for home. Once there i checked the exhaust pipes for heat. Sure enough, cylinder two was cold. I proceeded to do the following:
1) Pulled all wires from the cylinder and plug 2. The plug looked fine upon inspection.
2) Put plug 2 back into wire 2 and ran starter, no spark.
3) Put plug 2 into wire 6 and ran the starter, spark. Spark appeared weak.
4) Put plug 2 back into wire 2 and ran the starter, spark. Spark appeared weak.
5) Put an old plug from the last change into cylinder 2 and put all wires back on.
6) started the bike and went for a short ride. Runs like a scalded dog again.

Could i have a failing plug wire, failing coil or maybe just a crappy plug??
I'm running NGK #7's.

Thanks in advance.
AJ

[John Schmidt]

Well, you put the old plug back in #2 and it runs fine. Think about that for about 2 seconds!

[LB]

Yep, I've had new plugs fail right out of the box.

[Martin2001]

To John's point, I put the plug that was in it when the cylinder ran cold yesterday back in it today. No issues, it also ran fine.

[LB]

To John's point, I put the plug that was in it when the cylinder ran cold yesterday back in it today. No issues, it also ran fine.

If that's the case, you have a bad plug wire.

[John Schmidt]

Or possibly a bad connection at the coil. The wires have a screw on cap at the coil with a locking collar underneath it. The coil has a sharp protrusion that pokes into the center of the wire when you press it in, then you screw down the cap, works sorta like a compression fitting for plumbing. Another possibility is a bad cap at that plug, the innards can be removed to see if you have a cracked insulator or resistor.