#4 Cylinder Dead - Can't find Cause

Just for a quick test id take #4 plug and switch with say #1 ..
I have heard of a plug firing out of the engine and not in before ..

Valves ok?
Are they opening and closing completing the compression cycle, I suggest cranking it over with the plugs out and see if there's difference in the "noises" coming out of the holes. After sitting for a while it may be a stuck valve guide, but the proper way would be to take the tappet covers off.
If you have spark and fuel, the only other thing missing is air to intiate the compression cycle.
Another remote possibilty is the coil is breaking down and only delivering a partial spark, a broken or damaged spark lead, and maybe a stuffed plug that works occasionally? (Usually they work or don't)
Failing all that, a compression test may shed some light.

[WingMan71]

All,

I'm still in progress on my '83 GS650GL restoration project. (Just a reminder that the bike it sat in storage since 1999.)

Also, I spent about 20 hours total removing, cleaning, rebuilding, and re-installing the carbs. I followed the "CV Carburetor Rebuild Guide" on BassCliff's web site to the letter. Didn't skip any steps. These carbs were like new when I was done.

I finally got the tank cleaned and lined with a POR15 kit so I was excited to get some gas in her last night and see if she would actually fire up.

She did! But only on three cylinders. #1, #2, and #3 are working, but not #4. (Even running on only three cylinders she ran pretty good.)

After several minutes of running, I noticed that the exhaust pipe on #4 cylinder was not getting hot like the other three. So, I pulled the plug boot off of #4 and NO difference! #4 was dead.

Next I pulled the #4 spark plug out, hooked it back up to the boot and laid it against the side of the engine. She HAS spark. So, not that's not the problem.

This morning after the engine cooled down I loosened the drain screw on the #4 carb fuel bowl. There WAS fuel in the bowl! I was not expecting to see fuel in there, knowing that the spark was good on #4.

I didn't notice whether the brand new spark plug that I removed from #4 for the spark test was wet from unburned fuel. It did not seem wet to me.

So, where do I look next?

Could it still be the #4 carb, even though it has fuel in the bowl and has all new/cleaned guts? If so, where's the blockage?

I have not checked compression yet, but I do have an automotive compression gauge. (Just don't know if I have the proper fitting to connect to the spark plug hole on this bike.)

I'm not hearing any suspicious engine noises at all, no valve clatter, no noises of any kind. Engine revs up high on 3 cylinders just fine with no strange noises.

I have not checked valve clearance yet, but can't imagine that the valves could be SO far off that the cylinder would be completely dead.

HELP! WHAT DO I CHECK NEXT?

???