Not firing on all cylinders?

[lordsir]

Lordsir here. Long time reader, first time poster. I have a '94 GSXF 750 USA non California model Katana. It runs pretty rough. When I measure the temp of the header individully with an infrared temp meter they read as follows-
#1:200-250deg.F #2:200-250deg.F #3:70-90deg.F #4:500-600deg.F
I have checked the spark plugs, coils, coil wires, ignitor, carbs, and battery.
I am at a loss as to what it could be. With the bike running i can pull the plug wire for the #3, #2, or even both at the same time and it does not affect the engine operation at all. Which seems kinda weird to me. Here are pics of the exhaust, etc.... Notice how shinny the #3 pipe is.
Any advice would be greatly appreciated. Also I live in Oregon so the weather is not a factor.
IMG_3884[1].jpg

IMG_3881[2].jpg

IMG_3887[1].jpg

mini kat1.jpg

[92xjunker]

My guess is Either cabs are still dirty (pilot circuit),low compression or you need to sync the carbs. I'm going more towards dirty carbs and a sync is needed.

[shpielers]

+1
either that, or #3 or running pig rich, and #4 is running lean.

With #3 at that temp, almost seems like it's not running on that cylinder at all

["K"]

When was the last valve clearance check?

[92xjunker]

They would have to be waaaaay out to cause that much variance between cylinders.

[FJCharlie]

if valves arent closing as they should you a get a mess...
go for carbs, clean and retune, if it doesnt help go for valves and if that doesnt help then mess with cylinders..